[amsat-bb] Re: antenna project
PICTURES!! No Pics, didn't happen! :) W5LMM On 5/6/2014 11:04 AM, george hinkle wrote: I've been working on a very large antenna project. To day I will solder my last two connector's. Then a little preflight inspection. I hope this works I've been working on the on and off all winter. If the antennas work it's off to my transverters and flex radios putting them on the birds. george wi9i ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Question
Hi Doug, I doubt that I have greater understanding of antennas than you do, but I'll give your question a shot. Actually, I have been working on circularly polarizing the ARROWS with the WRAPS lately, a work still in progress but almost complete. So I am throwing out the draft information I have been working on to date. You can circularly polarize a pair of ARROWs and they actually work well together from my experience (one of the reasons I suspect is that the feed system of the individual antennas is very well matched). If you are mounting the two antennas virtually on the same boom (sticking them right next to each other) it might get pretty crowded and interactions complicated. I have mounted two ARROWs separated horizontally about 3 feet apart with pretty good success. I have done this with stock ARROWs, and also with one side with the two meter elements, and the other side with the 70 CM elements (had to drill extra holes for the 70 CM mod), both ways worked about the same. The tricky part is coming up with the right feed lines (the transformer lines and the phasing line). I have a first draft of an article I am working on that describes my latest effort to come up with a polarity switching arrangement for ARROWs with the WRAPS, it can be downloaded here (if you have download issues, let me know and I'll try and get it to you another way). Click here to view Circling the WRAPS https://www.dropbox.com/l/xvKKUtfwUN5gFhGyCiXjua? I will be adding to the conclusion of the piece some suggestions on where to include an external diplexer in the line to handle the single feed line issue that you mention in your post. Anyway, I hope this will stimulate some ideas. Mark Mark Spencer, WA8SME 860-381-5335 mspen...@arrl.org ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Check
You'll get some polarity fading, abd the feedline type and length is very important, but yes, they will work. 73, Drew KO4MA Sent from my iPhone On Nov 27, 2013, at 11:28 AM, Jeff Kelly jke...@verizon.net wrote: I am planning on rebuilding my satellite station with smaller linear beam antennas. I just don’t have room for the 22C and 40CX. The plan is to use a 3 element 2 meter M2 beam and a 6 element 435 M2 beam on a Yaesu rotator. I still have my 847 and a 2 meter amp if needed. Would these antennas work ok for FuneCubeSat? Thanks, Jeff K2SDR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Check
Jeff This may not be news to you in which case Delete the message. Drew mentions feedline. Especially at 435 MHz, the loss of signal (both received and transmitted) is something to consider. I have a 50 foot tower and a total of about 95 feet of coax between the antenna and the rig. A good quality coax such as Times Microwave 400 on two meters works well. I put in hard line for 435 MHz as well as a mast mounted preamp because the line loss at 100 ft is significant at UHF and higher frequencies. Here is a link which will show how many dB of loss you will have at different frequencies for different types of coax. http://www.saarsham.net/coax.html If you have 100 feet of RG-8 coax you will lose half your power in the line. AND the received signal is similarly affected. 73 Rolf NR0T On Wed, Nov 27, 2013 at 11:37 AM, Andrew Glasbrenner glasbren...@mindspring.com wrote: You'll get some polarity fading, abd the feedline type and length is very important, but yes, they will work. 73, Drew KO4MA Sent from my iPhone On Nov 27, 2013, at 11:28 AM, Jeff Kelly jke...@verizon.net wrote: I am planning on rebuilding my satellite station with smaller linear beam antennas. I just don’t have room for the 22C and 40CX. The plan is to use a 3 element 2 meter M2 beam and a 6 element 435 M2 beam on a Yaesu rotator. I still have my 847 and a 2 meter amp if needed. Would these antennas work ok for FuneCubeSat? Thanks, Jeff K2SDR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna element and Boom material
I am wondering about going from 1/4 inch tound elements to about 3/8 inch square would effect the performance of this antenna. Mike Hoblinski N6IMF It definitely will Mike, but not in a positive/negative way per se. Let me explain. If you follow an optimized design that called for 1/4 inch round elements and substitute 3/8 in square tubing, the impedance and SWR bandwidth characteristics will change in the general sense, and these changes may or may not be desirable. I do not have the experience with LP antenna implementations that I do with Yagi or wire antennas, so perhaps there are other issues to consider. I would suspect that the low SWR points across the bands would simply shift. Changes in element diameters generally affects the electrical length, and in your example only a small amount. Russ K0WFS ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna element and Boom material
Hi Mike, N6IMF Russ, K0WFS and All on the list Generally speaking, if the elements of a yagi antenna are mechanically mounted insulated over a metallic boom like a round or square aluminum boom than the effect of the boom is to SHORT the lenght of the elements. The same shortening effect affect the element lenght if the elements are mounted directly in contact over or inside the metallic boom. No matter if the boom is round or square the lenght of the elements will be shortened in comparison to mount the elements over a plastic insulated boom. The plastic material as used for the boom do not affect the elements lenght. BTW in your case if you mount the elements over the boom in the same manner as designed for 1/4 inch round elements than to change the size elements from round 1/4 inch to about 3/8 inch square will affect only a small amount the center resonance of the antenna at the working center frequency and hence his change in VSWR and performance will be very small. Please read the following references on this matter: 1)P. Viezbicke, Yagi Antenna Designe NBS Technical Note 688, 1976, page. 6 2) Guenter Hoch, DL6WU, Extremely Long Yagi Antennas ,VHF Communications 3/82, pag.130 3) J.E. Pearson ,KF4JU, Element Lenght Disturbancies Due to End Chamfering and Insulated Metal Boom Proceedings of the 22nd Conference of the Central States VHF Society. 4) J. Lawson,Yagi Antenna Designe ARRL 1° Edition 1986 , pages. 7-11 5) The ARRL UHF/Microwave Experimenter's Manual,ARRL 1990 pages. 9-5 6) R. Bertelsmeier, DJ9BV, Yagi Antennas for 144 MHz DUBUS 1/1990 pag. 23 Have fun 73 de i8CVS Domenico - Original Message - From: Russ Ramirez russ.rami...@gmail.com To: amsat-bb@amsat.org Sent: Wednesday, August 14, 2013 6:46 PM Subject: [amsat-bb] Re: Antenna element and Boom material I am wondering about going from 1/4 inch tound elements to about 3/8 inch square would effect the performance of this antenna. Mike Hoblinski N6IMF It definitely will Mike, but not in a positive/negative way per se. Let me explain. If you follow an optimized design that called for 1/4 inch round elements and substitute 3/8 in square tubing, the impedance and SWR bandwidth characteristics will change in the general sense, and these changes may or may not be desirable. I do not have the experience with LP antenna implementations that I do with Yagi or wire antennas, so perhaps there are other issues to consider. I would suspect that the low SWR points across the bands would simply shift. Changes in element diameters generally affects the electrical length, and in your example only a small amount. Russ K0WFS ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna element and Boom material
two other things to remember also. 1- the antenna will probably cost more because everywhere i know of square tubing is more costly than roung, but if you have a sourse OK, 2- the wind load will be much larger, 30% roughly larger, the wind load of a 1 inch round tube is 0.6 the amount of a flat surface IE: square Joe WB9SBD Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 8/14/2013 8:24 PM, i8cvs wrote: Hi Mike, N6IMF Russ, K0WFS and All on the list Generally speaking, if the elements of a yagi antenna are mechanically mounted insulated over a metallic boom like a round or square aluminum boom than the effect of the boom is to SHORT the lenght of the elements. The same shortening effect affect the element lenght if the elements are mounted directly in contact over or inside the metallic boom. No matter if the boom is round or square the lenght of the elements will be shortened in comparison to mount the elements over a plastic insulated boom. The plastic material as used for the boom do not affect the elements lenght. BTW in your case if you mount the elements over the boom in the same manner as designed for 1/4 inch round elements than to change the size elements from round 1/4 inch to about 3/8 inch square will affect only a small amount the center resonance of the antenna at the working center frequency and hence his change in VSWR and performance will be very small. Please read the following references on this matter: 1)P. Viezbicke, Yagi Antenna Designe NBS Technical Note 688, 1976, page. 6 2) Guenter Hoch, DL6WU, Extremely Long Yagi Antennas ,VHF Communications 3/82, pag.130 3) J.E. Pearson ,KF4JU, Element Lenght Disturbancies Due to End Chamfering and Insulated Metal Boom Proceedings of the 22nd Conference of the Central States VHF Society. 4) J. Lawson,Yagi Antenna Designe ARRL 1° Edition 1986 , pages. 7-11 5) The ARRL UHF/Microwave Experimenter's Manual,ARRL 1990 pages. 9-5 6) R. Bertelsmeier, DJ9BV, Yagi Antennas for 144 MHz DUBUS 1/1990 pag. 23 Have fun 73 de i8CVS Domenico - Original Message - From: Russ Ramirez russ.rami...@gmail.com To: amsat-bb@amsat.org Sent: Wednesday, August 14, 2013 6:46 PM Subject: [amsat-bb] Re: Antenna element and Boom material I am wondering about going from 1/4 inch tound elements to about 3/8 inch square would effect the performance of this antenna. Mike Hoblinski N6IMF It definitely will Mike, but not in a positive/negative way per se. Let me explain. If you follow an optimized design that called for 1/4 inch round elements and substitute 3/8 in square tubing, the impedance and SWR bandwidth characteristics will change in the general sense, and these changes may or may not be desirable. I do not have the experience with LP antenna implementations that I do with Yagi or wire antennas, so perhaps there are other issues to consider. I would suspect that the low SWR points across the bands would simply shift. Changes in element diameters generally affects the electrical length, and in your example only a small amount. Russ K0WFS ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna element and Boom material
Hi Mike, Yes, the length of the elements will be affected. Fatter elements look electrically longer, I think, so they may need to be shortened a bit to compensate for a shift in frequency. Impedance may be affected as well. You will also need to keep the same mounting scheme, as to whether the elements are insulated from the main boom or not. But, experimenting is what it's all about. Build it and see how it performs. Adjust. Do it again. You will end up with a good antenna, and a practical knowledge of how to build it, when you're done. Then let us know how you did it. Good luck, Greg KO6TH Mike Hoblinski wrote: I was looking at constructing a Log Periodic antenna and was wondering about useing square material instead of round elements. The plans call out 1/4 round hollow tube for the elements. I ran across some aluminum extrusion material from a company called Microrax http://www.microrax.com/ that sells small aluminum extrusion and brackets plus hardware. Their extrusions are 10mm square and come in legnths up to 35 inches. I was looking at going with some larger extrusion material for the boom. All of the extrusion material has nice channels cut into it that could be used for element spacing adjustment and easy mounting. My other thought was to tap the ends of the elements and add stainless steel screws to adjust the legnths. I am wondering about going from 1/4 inch tound elements to about 3/8 inch square would effect the performance of this antenna. Mike Hoblinski N6IMF ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna direction calibration
I actually use the sun for aligning the antennas. SatPC32 comes with a program called SuM, which can point the antennas directly at the sun (or moon!). To align the antennas, I look at the shadow of the antennas on the ground, and adjust until the shadow is minimum size. It's really easy, (and you don't need to look at the sun to do this type of alignment). 73! Dave KB5WIA http://kb5wia.blogspot.com On Wed, Jul 17, 2013 at 8:29 PM, Rodney Waln kc0...@yahoo.com wrote: hi, well i will through my $0.2 in, for my home station to get as accurate as i can, i listen for a satellite beacon on one of the SSB's set the radio to track and satpc32 to track, have a radio or wireless mic and take an ht to the roof with me,when i hear the cw tone that sounds ok i am set. then fine tune things from there, mind you i am at a 10* handicap do to thre hills around me, so it takes a few tries, i also do it almost the same way for or portable, but you get the idea, the FM sat's are point and shoot, Rodney kc0zhf ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna direction calibration
Hi Dave, KB5WIA To align the antennas, I don't look at the shadow of the antennas on the ground, but I adjust the position of the antenna in Azimuth and Elevation until the Sun-Noise received in my Signal Streng indicator is the maximum. This is very important particularly at very high frequencies using a dish because the feed can be wrongly mounted sligtly off point from the center of the dish and the pencil of the radiation pattern of the dish can be affected by a squint not visible looking at the shadow of the feed at the center of the dish but still existing from the point of view of receiving a less strenght of Sun-Noise. 73 de i8CVS Domenico - Original Message - From: David Palmer KB5WIA kb5...@amsat.org To: Rodney Waln kc0...@yahoo.com Cc: amsat-bb@amsat.org Sent: Thursday, July 18, 2013 7:15 PM Subject: [amsat-bb] Re: Antenna direction calibration I actually use the sun for aligning the antennas. SatPC32 comes with a program called SuM, which can point the antennas directly at the sun (or moon!). To align the antennas, I look at the shadow of the antennas on the ground, and adjust until the shadow is minimum size. It's really easy, (and you don't need to look at the sun to do this type of alignment). 73! Dave KB5WIA http://kb5wia.blogspot.com On Wed, Jul 17, 2013 at 8:29 PM, Rodney Waln kc0...@yahoo.com wrote: hi, well i will through my $0.2 in, for my home station to get as accurate as i can, i listen for a satellite beacon on one of the SSB's set the radio to track and satpc32 to track, have a radio or wireless mic and take an ht to the roof with me,when i hear the cw tone that sounds ok i am set. then fine tune things from there, mind you i am at a 10* handicap do to thre hills around me, so it takes a few tries, i also do it almost the same way for or portable, but you get the idea, the FM sat's are point and shoot, Rodney kc0zhf ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna direction calibration
hi, well i will through my $0.2 in, for my home station to get as accurate as i can, i listen for a satellite beacon on one of the SSB's set the radio to track and satpc32 to track, have a radio or wireless mic and take an ht to the roof with me,when i hear the cw tone that sounds ok i am set. then fine tune things from there, mind you i am at a 10* handicap do to thre hills around me, so it takes a few tries, i also do it almost the same way for or portable, but you get the idea, the FM sat's are point and shoot, Rodney kc0zhf ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna direction calibration
The North Star is the best. even tho it itself is a little off from exactly North also. But less than a degree. About 0.6 degrees or so. If that isn't accurate enough there are tables you can look up to learn what we call cumulation of Polaris. This is a time when Polaris (AKA The North Star) is directly above or below the pole. and then would give you an exact AZ setting, then 6 hours before or later Polaris would be east or west of the pole exactly and this would give you an exat elevation setting. Never use magnetic readings. depending where you live it can be a LOT off. Joe WB9SBD Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 7/14/2013 11:01 PM, John Fickes wrote: Bob What I do ( and I'm not sure I'm right,but seems to work ) is to use the North star to calibrate. I live at 41.2* latitude, so if I crank my antennas to 41* elevation and point north 0* azimuth I should be pretty close. I also live at 1* magnetic declination, not much so I don't worry much about that. Now I don't do much EME as I don't have any power, but I've monitored EME and this seems to get me pretty close. I will also be glad to see what others do to calibrate. 73 John KC0BMF ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna direction calibration
Only if your program is accurate and operating correctly. The Sun is not a smooth mover, at say Noon, it is not due south in AZ all the time. Joe WB9SBD Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 7/14/2013 11:06 PM, George Henry wrote: The sun is probably even better... George, KA3HSW - Original Message - From: Bob- W7LRD w7...@comcast.net To: amsat-bb@amsat.org Sent: Sunday, July 14, 2013 10:29 PM Subject: [amsat-bb] antenna direction calibration You'd think I would have this figured out by now. I never paid very close attention to exact antenna direction until now. I mean the satellite was always within the beam pattern. I tried the SuM part of Satpc32. I am thinking of trying some EME, and I looked up the boom of the yagi' and I was about 8* high and maybe 10* to the right of the moon, still probably within the half power point of the beams. This is where the obsessive part comes along, should I use the moon as the grand phooba of calibration? Or compass true/mag. I mean the moon is pretty consistent. As always the collective thoughts of this bb are never wrong. 73 Bob W7LRD Seattle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna direction calibration
There's also the Heavens Above website, which will tell you exactly when local Noon is. The Sun will be at 180 degrees Az at that time. The disadvantage of this is that it will also be high in the sky, reducing accuracy. Unless you're at a high latitude... Bob wins on this one. Greg KO6TH Joe n...@mwt.net wrote: Only if your program is accurate and operating correctly. The Sun is not a smooth mover, at say Noon, it is not due south in AZ all the time. Joe WB9SBD Sig The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 7/14/2013 11:06 PM, George Henry wrote: The sun is probably even better... George, KA3HSW - Original Message - From: Bob- W7LRD w7...@comcast.net To: amsat-bb@amsat.org Sent: Sunday, July 14, 2013 10:29 PM Subject: [amsat-bb] antenna direction calibration You'd think I would have this figured out by now. I never paid very close attention to exact antenna direction until now. I mean the satellite was always within the beam pattern. I tried the SuM part of Satpc32. I am thinking of trying some EME, and I looked up the boom of the yagi' and I was about 8* high and maybe 10* to the right of the moon, still probably within the half power point of the beams. This is where the obsessive part comes along, should I use the moon as the grand phooba of calibration? Or compass true/mag. I mean the moon is pretty consistent. As always the collective thoughts of this bb are never wrong. 73 Bob W7LRD Seattle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna direction calibration
The sun is probably even better... George, KA3HSW - Original Message - From: Bob- W7LRD w7...@comcast.net To: amsat-bb@amsat.org Sent: Sunday, July 14, 2013 10:29 PM Subject: [amsat-bb] antenna direction calibration You'd think I would have this figured out by now. I never paid very close attention to exact antenna direction until now. I mean the satellite was always within the beam pattern. I tried the SuM part of Satpc32. I am thinking of trying some EME, and I looked up the boom of the yagi' and I was about 8* high and maybe 10* to the right of the moon, still probably within the half power point of the beams. This is where the obsessive part comes along, should I use the moon as the grand phooba of calibration? Or compass true/mag. I mean the moon is pretty consistent. As always the collective thoughts of this bb are never wrong. 73 Bob W7LRD Seattle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna direction calibration
Bob What I do ( and I'm not sure I'm right,but seems to work ) is to use the North star to calibrate. I live at 41.2* latitude, so if I crank my antennas to 41* elevation and point north 0* azimuth I should be pretty close. I also live at 1* magnetic declination, not much so I don't worry much about that. Now I don't do much EME as I don't have any power, but I've monitored EME and this seems to get me pretty close. I will also be glad to see what others do to calibrate. 73 John KC0BMF ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna direction calibration
Hi Bob, I use the Sun, late in the afternoon. The satellite program tells me where the Sun should be, and I aim the rotor to match. Then up on the roof I go, to align the rotor mount so the shadow runs down the beam. Worked quite well for aiming at AO-40. Of course in the Pacific Cloudy West, you may have to wait awhile for a clear day... Greg KO6TH Bob- W7LRD w7...@comcast.net wrote: You'd think I would have this figured out by now. I never paid very close attention to exact antenna direction until now. I mean the satellite was always within the beam pattern. I tried the SuM part of Satpc32. I am thinking of trying some EME, and I looked up the boom of the yagi' and I was about 8* high and maybe 10* to the right of the moon, still probably within the half power point of the beams. This is where the obsessive part comes along, should I use the moon as the grand phooba of calibration? Or compass true/mag. I mean the moon is pretty consistent. As always the collective thoughts of this bb are never wrong. 73 Bob W7LRD Seattle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Question
I run linear polarization, and just live with the fades. Saves a lot of complexity and headaches! 73, Jim KQ6EA On 09/15/2012 06:47 PM, Thomas Doyle wrote: I was listening to a couple of guys on FO-29 having a nice chat about satellite antenna polarization. They were trying to figure out what type of polarization FO-29 used. They looked at the picture of FO-29 on the AMSAT web site and decided that it was not circular. Someone told me that it was circular so I started looking for information. Found this page by WD0E which is quite nice. http://www.amsat.org/amsat-new/information/faqs/pswitch.php Is there a more current page that contains this type of information. tnx W9KE Tom Doyle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Question
- Original Message - From: Thomas Doyle tomdoyle1...@gmail.com To: amsat-bb@amsat.org Sent: Saturday, September 15, 2012 8:47 PM Subject: [amsat-bb] Antenna Polarization Question I was listening to a couple of guys on FO-29 having a nice chat about satellite antenna polarization. They were trying to figure out what type of polarization FO-29 used. They looked at the picture of FO-29 on the AMSAT web site and decided that it was not circular. Someone told me that it was circular so I started looking for information. Found this page by WD0E which is quite nice. http://www.amsat.org/amsat-new/information/faqs/pswitch.php Is there a more current page that contains this type of information. tnx W9KE Tom Doyle Hi Tom, W9KE For the antenna polarization of FO-29 please read belove: --- AMSAT NEWS SERVICE BULLETIN 254.S1 FROM AMSAT HQ SILVER SPRING, MD, September 10, 2012 TO ALL RADIO AMATEURS BID: $WSR-254.S1 FO-29 JAS-2 Catalog number: 24278 Launch Date: August 17, 1996 Mode and Antenna Polarization: V: RHCP U: RHCP i8CVS Note: Following my experience on FO-29 I can add the information belowe: FO-29 is RHCP circularly polarized both in uplink and downlink and has a fixed sense both up and down, but because of its orbit geometry and motion, continuously good signals through it for an entire pass can only maintained if the antennas ground station sense is switched, RHCP to LHCP and vice versa in 70 cm and 2 meters usually several times and on both uplink and downlink and so polarization switching relays on board of both up and down antennas are recommended. Read please my articles about polarization switching published on the AMSAT-Journal March/April 2007 and May/June 2007 73 de i8CVS Domenico ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Question
Domenico, Thanks for the reply. I am slowly building my sat station back to what it was back in the day when I had a pair of KLM antennas with polarization switching. I have recently added a switchable polarization 70 cm antenna to my current station and am amazed at how often during an FO-29 pass it is necessary to change polarization. My memory is not what it should be but I do not remember as much switching being necessary when using AO-10 era sats. Perhaps they were more stable or the pass was so long that it did not seem like it required as much switching. In 1911, Albert Abraham Michelson discovered that light reflected from the golden scarab beetle Chrysina resplendens is preferentially left-handed. After reading this I wondered if it is possible to create a reflector for RF that would do something similar to what this tiny insect does without even trying. When I asked how to change the polarization sense of a lindenblad antenna I was going to build the author of the article told me that it was not necessary to switch it because there were so many reflections it would not matter. Perhaps a controlled reflective surface would work. tnx 73 W9KE Tom Doyle On Sat, Sep 15, 2012 at 3:00 PM, i8cvs domenico.i8...@tin.it wrote: - Original Message - From: Thomas Doyle tomdoyle1...@gmail.com To: amsat-bb@amsat.org Sent: Saturday, September 15, 2012 8:47 PM Subject: [amsat-bb] Antenna Polarization Question I was listening to a couple of guys on FO-29 having a nice chat about satellite antenna polarization. They were trying to figure out what type of polarization FO-29 used. They looked at the picture of FO-29 on the AMSAT web site and decided that it was not circular. Someone told me that it was circular so I started looking for information. Found this page by WD0E which is quite nice. http://www.amsat.org/amsat-new/information/faqs/pswitch.php Is there a more current page that contains this type of information. tnx W9KE Tom Doyle Hi Tom, W9KE For the antenna polarization of FO-29 please read belove: --- AMSAT NEWS SERVICE BULLETIN 254.S1 FROM AMSAT HQ SILVER SPRING, MD, September 10, 2012 TO ALL RADIO AMATEURS BID: $WSR-254.S1 FO-29 JAS-2 Catalog number: 24278 Launch Date: August 17, 1996 Mode and Antenna Polarization: V: RHCP U: RHCP i8CVS Note: Following my experience on FO-29 I can add the information belowe: FO-29 is RHCP circularly polarized both in uplink and downlink and has a fixed sense both up and down, but because of its orbit geometry and motion, continuously good signals through it for an entire pass can only maintained if the antennas ground station sense is switched, RHCP to LHCP and vice versa in 70 cm and 2 meters usually several times and on both uplink and downlink and so polarization switching relays on board of both up and down antennas are recommended. Read please my articles about polarization switching published on the AMSAT-Journal March/April 2007 and May/June 2007 73 de i8CVS Domenico -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Question
- Original Message - From: Thomas Doyle tomdoyle1...@gmail.com To: i8cvs domenico.i8...@tin.it Cc: Amsat - BBs amsat-bb@amsat.org Sent: Saturday, September 15, 2012 10:34 PM Subject: Re: [amsat-bb] Antenna Polarization Question Domenico, Thanks for the reply. I am slowly building my sat station back to what it was back in the day when I had a pair of KLM antennas with polarization switching. I have recently added a switchable polarization 70 cm antenna to my current station and am amazed at how often during an FO-29 pass it is necessary to change polarization. My memory is not what it should be but I do not remember as much switching being necessary when using AO-10 era sats. Perhaps they were more stable or the pass was so long that it did not seem like it required as much switching. snip tnx 73 W9KE Tom Doyle Hi Tom, W9KE Using AO-10 and in general HEO satellites like AO-13 and AO40 switching polarization was less necessary than using LEO satellites because most of the time the satellite antennas were oriented toward the earth with a small squint angle so that the polarization changed very slowly mostly due only to the Faraday polarization rotation when the wave passed through the ionosphere. BTW the above HEO satellites were spinning over the Z axis generating the so called spin modulation wich sounded like WOW...WOW.WOW.WOW Only the AO40 downlink at 2401 MHz was less affected by the polarization rotation due to Faraday effect and less affected by the spin modulation. Hope that some time in the future the HEO satellite P3E will be placed in orbit ! 73 de i8CVS Domenico ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna
It's been done a number of times, though like most things, it's a compromise that will work better for some satellites than others. The thing about the Elk or Arrow that works well with their usual (hand-held) use is that they are linearly polarized, but mounted on a 3-axis rotor system (your wrist) which can compensate for Azimuth, Elevation, and also rotate to match the polarization of a linearly polarized satellite. Many satellites are linear right now, so a fixed mounting will mean you will get some deep fading as the satellite spins. It's not unworkable - I have an Az / El rotor system with a vertically polarized 2m beam (not an Arrow), and I've learned to adapt. The fixed Elevation is actually less of an issue. Put it at about 20 degrees up, and you should be good to go. Satellites spend most of their time NOT being directly overhead, and those antennas are not so sharp in their reception pattern anyway. And when the satellite is overhead it's also a lot closer, so that compensates a bit. The last tip is that I don't think either antenna were designed for extended outdoor use, so they may deteriorate faster than otherwise, depending on your particular weather patterns. But, as with most thing in this hobby, give it a try. The worst thing that will happen is that you will learn something. Greg KO6TH ld.lu...@frontier.com wrote: This may have been discussed before forgive me if it has I am new at this. I was wondering if an Elk or Arrow antenna mounted on a mast at an angle with a TV rotor would work as a base antenna for Satellite work. Has anyone done this and any tips on how you have been successful. If this does not work what would be the best antenna other than beams for under $200.00 to do this? Thanks for your information. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna
Id, I have sent you my informal 'construction article' along with pictures direct. This is an excellent compromise and economical...and it works great. I use the Elk because, as you will see in the photos, you can center the weight mass right over the RS rotor. I don't see how you could do that with an Arrow, so I think the Arrow will be way too much weight hanging out there. As you will see in the photos, you can paint ( any solid non-metallic color) all the pvc pieces for weather an uv protection. The antenna and rotor can be protected with multiple coasts of Rustoleum claer Also, I think Bob Brunniga (from this group) has documented that 15 deg fixed is the best overall el setting. You can also modify my design to have the preamp on top. (mine is in the shack) This setup got me most of my VUCC (but so did AO-51 !!) and it works. GL, Ted, K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of ld.lu...@frontier.com Sent: Sunday, August 19, 2012 2:18 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna This may have been discussed before forgive me if it has I am new at this. I was wondering if an Elk or Arrow antenna mounted on a mast at an angle with a TV rotor would work as a base antenna for Satellite work. Has anyone done this and any tips on how you have been successful. If this does not work what would be the best antenna other than beams for under $200.00 to do this? Thanks for your information. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna
Also, I think Bob Brunniga... has documented that 15 deg fixed is the best overall el setting. Yep, that puts the main beam on the horizon where you need it most and where satellties spend over 70% of their time. Even at 15 degrees, you still are within 1 dB of max gain on the horizon. That same amount of gain covers up to 30 degree too. And anything above 30 degrees is 6 to 10 dB CLOSER and does not need much gain. Above 70 degres there begins to be a null, but satellites will be in that null less than 1% of the overall contact time. Bob, WB4APR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna
Hi, I have used a very similar setup in the past with a Sandpiper dual band yagi (3 elements on 2m, 5 on 70cms) so the Elk, or Arrow antenna should work just as well. I had mine set at a fixed elevation of around 30 degrees, this was great for ISS, and AO-51 when she was active, good luck on the birds. 73 de Matty MD0MAN Message: 9 Date: Sun, 19 Aug 2012 05:17:41 -0400 From: ld.lu...@frontier.com To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Message-ID: ohellopgpojmodfafmieeekgcpaa.ld.lu...@frontier.com Content-Type: text/plain; charset=iso-8859-1 This may have been discussed before forgive me if it has I am new at this. I was wondering if an Elk or Arrow antenna mounted on a mast at an angle with a TV rotor would work as a base antenna for Satellite work. Has anyone done this and any tips on how you have been successful. If this does not work what would be the best antenna other than beams for under $200.00 to do this? Thanks for your information. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Thanks to Domenico for sharing the work done by K4KJ. It is amazing how much good information there is out there. It takes a bit of digging to find it but it is worth the effort. The configuration shown in figure 14 looks promising but probably too difficult to put on a sat. W9KE Tom Doyle On Sat, Aug 4, 2012 at 10:18 PM, i8cvs domenico.i8...@tin.it wrote: Hi All, I agree completely with Bob, WB4APR and this is what is wery well explained into the article CIRCULAR POLARIZATION by K4KJ, a zipped file 5 MB long available from me. 73 de i8CVS Domenico - Original Message - From: Bob Bruninga bruni...@usna.edu To: Thomas Doyle tomdoyle1...@gmail.com Cc: amsat-bb@amsat.org; andrew abken kn...@hotmail.com Sent: Sunday, August 05, 2012 12:24 AM Subject: [amsat-bb] Re: Antenna Polarization Technical Question Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Bob, Just a reminder, a QFH antenna is circularly polarized over the whole envelope of the antenna. A sharp null exists on the back side. A one wavelength, one turn has gain at low angle side radiation and a 4 dB loss overhead, where the distance to the ground station is the smallest. Certainly this is a good fit for satellites. Turnstile antennas and patch antennas are linear polarized at the sides and of course are the easiest to implement on a satellite. My point is all circular antennas are not equal and having an antenna with gain on the sides opposed to the center of the antenna is very desirable. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Bob Bruninga Sent: Saturday, August 04, 2012 3:25 PM To: Thomas Doyle Cc: amsat-bb@amsat.org; andrew abken Subject: [amsat-bb] Re: Antenna Polarization Technical Question Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Hi Art, KC6UQH It is correct that a QFH is circularly polarized over the whole envelope of the antenna.If it is left wound the polarization is RHCP and if it is right wound the resulting polarization is LHCP. By the way the point is the satellite antenna. If the satellite antenna is made using two crossed dipoles mounted in the same mechanical plane and are supplied with 90° out of phase than the radiated polarization is RHCP along one axial direction and LHCP along the other axial direction. Since the satellite is thumbling orbiting in the space than the polarization coming from the satellite to earth or coming from the ground station to the satellite is continuing changing from RHCP to LHCP to linear passing through elliptical. The bad point is that a QFH can only radiate RHCP or LHCP depending on it's winding direction so that using only one QFH the QSB generated by the satellite thumbling cannot be completely eliminated and two switchable QFH's one RHCP and the other one LHCP would be necessary. 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'Bob Bruninga ' bruni...@usna.edu; 'Thomas Doyle' tomdoyle1...@gmail.com Cc: amsat-bb@amsat.org; 'andrew abken' kn...@hotmail.com Sent: Sunday, August 05, 2012 10:44 PM Subject: [amsat-bb] Re: Antenna Polarization Technical Question Bob, Just a reminder, a QFH antenna is circularly polarized over the whole envelope of the antenna. A sharp null exists on the back side. A one wavelength, one turn has gain at low angle side radiation and a 4 dB loss overhead, where the distance to the ground station is the smallest. Certainly this is a good fit for satellites. Turnstile antennas and patch antennas are linear polarized at the sides and of course are the easiest to implement on a satellite. My point is all circular antennas are not equal and having an antenna with gain on the sides opposed to the center of the antenna is very desirable. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Bob Bruninga Sent: Saturday, August 04, 2012 3:25 PM To: Thomas Doyle Cc: amsat-bb@amsat.org; andrew abken Subject: [amsat-bb] Re: Antenna Polarization Technical Question Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now
[amsat-bb] Re: Antenna Polarization Technical Question
Domenico, You are correct, the crossed dipoles fed in quadrature when on axis exhibit LH and RH circular patterns, but 90 degrees from axis they are linearly polarized. This gives poor performance at low angles as well as requiring both RH and LH rotations for a full pass reception. Obviously the QFH antenna to be effective should point down at the earth, with the sides pointing to the horizon and the backside towards outer space. The one wave one turn can be optimized,(Length to Diameter ratio)to provide best radiation at the horizon. This will give good performance when the satellite is near zenith as well as provide improved performance at low elevations. Circular polarization does help to eliminate multipath and provide a steady copy, even while the antenna is mechanically rotating with the satellite for stabilization and temperature stability. Art, KC6UQH -Original Message- From: i8cvs [mailto:domenico.i8...@tin.it] Sent: Sunday, August 05, 2012 3:27 PM To: AMSAT-BB; Bob Bruninga ; kc6...@cox.net; Thomas Doyle Subject: Re: [amsat-bb] Re: Antenna Polarization Technical Question Hi Art, KC6UQH It is correct that a QFH is circularly polarized over the whole envelope of the antenna.If it is left wound the polarization is RHCP and if it is right wound the resulting polarization is LHCP. By the way the point is the satellite antenna. If the satellite antenna is made using two crossed dipoles mounted in the same mechanical plane and are supplied with 90° out of phase than the radiated polarization is RHCP along one axial direction and LHCP along the other axial direction. Since the satellite is thumbling orbiting in the space than the polarization coming from the satellite to earth or coming from the ground station to the satellite is continuing changing from RHCP to LHCP to linear passing through elliptical. The bad point is that a QFH can only radiate RHCP or LHCP depending on it's winding direction so that using only one QFH the QSB generated by the satellite thumbling cannot be completely eliminated and two switchable QFH's one RHCP and the other one LHCP would be necessary. 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'Bob Bruninga ' bruni...@usna.edu; 'Thomas Doyle' tomdoyle1...@gmail.com Cc: amsat-bb@amsat.org; 'andrew abken' kn...@hotmail.com Sent: Sunday, August 05, 2012 10:44 PM Subject: [amsat-bb] Re: Antenna Polarization Technical Question Bob, Just a reminder, a QFH antenna is circularly polarized over the whole envelope of the antenna. A sharp null exists on the back side. A one wavelength, one turn has gain at low angle side radiation and a 4 dB loss overhead, where the distance to the ground station is the smallest. Certainly this is a good fit for satellites. Turnstile antennas and patch antennas are linear polarized at the sides and of course are the easiest to implement on a satellite. My point is all circular antennas are not equal and having an antenna with gain on the sides opposed to the center of the antenna is very desirable. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Bob Bruninga Sent: Saturday, August 04, 2012 3:25 PM To: Thomas Doyle Cc: amsat-bb@amsat.org; andrew abken Subject: [amsat-bb] Re: Antenna Polarization Technical Question Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May
[amsat-bb] Re: Antenna Polarization Technical Question
Andy, I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. Perhaps there is some sort of Faraday Rotation effect but I do not believe that it can change the direction of the circular polarized signal but who knows what magic things happen in the ether. tnx 73 W9KE Tom Doyle On Sat, Aug 4, 2012 at 12:44 PM, andrew abken kn...@hotmail.com wrote: Hi Tom, I thought fo-29 was transmitting circular. Would not surprise me if I was wrong:) Andy, kn6za ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Hi Tom, I have also noticed the switching of polarity as the sat travels over. What I have understood to be the mode by which this is occuring comes from the fact that circular polarized antennas change polarity as you move out of the main radiation lobe. The main lobe is circular one direction and the next lobe is reversed, and the next reversed back again. Hope someone can correct me if I have things fouled up. Andy Date: Sat, 4 Aug 2012 14:13:47 -0500 Subject: Re: [amsat-bb] Antenna Polarization Technical Question From: tomdoyle1...@gmail.com To: kn...@hotmail.com CC: amsat-bb@amsat.org Andy, I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. Perhaps there is some sort of Faraday Rotation effect but I do not believe that it can change the direction of the circular polarized signal but who knows what magic things happen in the ether. tnx 73 W9KE Tom Doyle On Sat, Aug 4, 2012 at 12:44 PM, andrew abken kn...@hotmail.com wrote: Hi Tom, I thought fo-29 was transmitting circular. Would not surprise me if I was wrong:) Andy, kn6za ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Bob, Thanks for the reply. A student of mine once told me that if someone tells you something is easy - it is not. Even though this is not only easy but very easy I still need a slight clarification. I think it boils down to the orientation of the satellite relative to the center of the earth. If the satellite was a clock and the face of the clock was oriented toward the center of the earth the I believe the clock would appear to rotate CW on both ends of the pass. If the side of the clock rather than the face of the clock was oriented toward the center of the earth it would appear to rotate one way at the start of the pass and the other way at the end of the pass because we would be looking at the clock from the other side. I believe this is the basis of the very easy explanation you offered. Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Perhaps people selling antenna circularity switches would like it but other than that I do not understand why it would be done. I am most likely missing something important. tnx 73 W9KE Tom Doyle On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
I can't explain it but have noticed the same polarity changes during a pass. Like S-9 to S-1/nothing switching between polarities with my antennas... it's been handy to actually have the ability to change polarities in the past for me. I do not have the ability to polarity switch on 2 meters, only 70 cM for the downlink. 73, Bob W1ICW On 8/4/2012 3:13 PM, Thomas Doyle wrote: Andy, I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. Perhaps there is some sort of Faraday Rotation effect but I do not believe that it can change the direction of the circular polarized signal but who knows what magic things happen in the ether. tnx 73 W9KE Tom Doyle On Sat, Aug 4, 2012 at 12:44 PM, andrew abken kn...@hotmail.com wrote: Hi Tom, I thought fo-29 was transmitting circular. Would not surprise me if I was wrong:) Andy, kn6za ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Tom, I don't think any one who designs a system wants this to occur, but as a function of overall system cost it is one of the unavoidable realities. Its actually a great compromise, because with only a 3db loss you can use a linear rec. antenna with no polarity switching, and avoid the large fading that would occur if the satellite was transmitting linear. Now if you have the money to build a satellite that can point itself at the receiving station at all times ie: geo synchronous:) then that would be the cats meow;) 73 Andy Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Perhaps people selling antenna circularity switches would like it but other than that I do not understand why it would be done. I am most likely missing something important. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. There are two perspectives in answering this. 1. You used the word maintain, which implies the ability of the spacecraft to control its attitude. That's commonly done for commercial and military satellites, but rarely (if ever) done for amateur satellites. It's just too complicated and too expensive for amateurs to allocate the resources to make it happen. 2. You also asked why anyone would WANT to maintain the orientation like that. In a more general sense, recognize that not every satellite is a communications satellite, supporting communications with terrestrial stations. Scientific missions often have to point a body-mounted sensor somewhere, and the comm payload has to adjust. For example, Hubble's main body IS the telescope, so it MUST point at the astronomical targets. For that mission, NASA paid for an articulated communications payload, but spacecraft don't always do that. 73, Steve W3HF ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Hi Thomas, W9KE In a separate email I have sent to you a very compreensive article explaining why during an orbit of a LEO satellite like FO-29 the changes in polarization is generated. 73 de i8CVS Domenico - Original Message - From: Thomas Doyle tomdoyle1...@gmail.com To: AMSAT-BB@amsat.org Sent: Saturday, August 04, 2012 4:46 PM Subject: [amsat-bb] Antenna Polarization Technical Question I had a actual qso on FO-29 the other day and during the contact circular polarization switching was discussed. The station I was talking with described a very large change in received signal strength when switching between LHCP and RHCP. I have heard other people mention this and I recall some change when using AO-10 with my switchable KLM's back in the good old days. I have been trying to figure out why there would be such a big change. Here is a collection of theories/questions. I would appreciate comments on any or all of them. This is a bit complex so a direct reply is probably best. - In a perfect world if the satellite antenna is linearly polarized LH-RH switching would not make any difference. - In a real world it is unlikely that the ground station receive antenna is truly circular. It is somewhat elliptical. Question: if the receive antenna has an elliptical pattern does the angle of the major axis change when switching LH - RH. This is a complex question related to the nature of what caused the elliptical distortion in the pattern. Perhaps someone has measured this. If the angle of the major axis receive antenna pattern changes when switching between LH and RH and the satellite antenna is linearly polarized this could account for some change in received signal strength. Other than that I am at a loss to explain why switching LH-RH on a receive antenna would cause a large change in the strength of a signal received from a linear antenna. tnx 73 W9KE Tom Doyle ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Hi Tom, KN6ZA With only a 3db loss you can use a linear rec. antenna with no polarity switching, and avoid the large fading that would occur if the satellite was transmitting circular RHCP or LHCP(but not linear as you stated) On the other side if you receive linear and the satellite transmit linearly with opposite polarity you get more than 20dB of fading. 73 de i8CVS Domenico - Original Message - From: andrew abken kn...@hotmail.com To: tomdoyle1...@gmail.com; amsat-bb@amsat.org Sent: Saturday, August 04, 2012 10:45 PM Subject: [amsat-bb] Re: Antenna Polarization Technical Question Tom, I don't think any one who designs a system wants this to occur, but as a function of overall system cost it is one of the unavoidable realities. Its actually a great compromise, because with only a 3db loss you can use a linear rec. antenna with no polarity switching, and avoid the large fading that would occur if the satellite was transmitting linear. Now if you have the money to build a satellite that can point itself at the receiving station at all times ie: geo synchronous:) then that would be the cats meow;) 73 Andy Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Perhaps people selling antenna circularity switches would like it but other than that I do not understand why it would be done. I am most likely missing something important. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization Technical Question
Hi All, I agree completely with Bob, WB4APR and this is what is wery well explained into the article CIRCULAR POLARIZATION by K4KJ, a zipped file 5 MB long available from me. 73 de i8CVS Domenico - Original Message - From: Bob Bruninga bruni...@usna.edu To: Thomas Doyle tomdoyle1...@gmail.com Cc: amsat-bb@amsat.org; andrew abken kn...@hotmail.com Sent: Sunday, August 05, 2012 12:24 AM Subject: [amsat-bb] Re: Antenna Polarization Technical Question Not sure why anyone would want to maintain the orientation of the satellite in such a way that would cause the direction of circular polarization to change during the path. Lets try this approach... As I said before, By the laws of physics, what comes out one side of a circular polarized low gain antenna as RHCP comes out the opposite side as LHCP. Now given that, and the fact that someone in Maryland is in the center of the RHCP beam, then by the laws of physics, the guy in California must see mostly LHCP. No matter how much one of those persons demands that he deserves the RHCP beam, by definition, someone else somewhere will get the LHCP one, and the geometry changes at least every 10 minutes or so and every time the spacecraft rotates a bit. So one might say, point it down then only the person in Kansas will see the main beam and those in CA or MD will be completely off the sides almost 70 degrees from the main beam. Mot people do not realize how LOW these satellites are. The only solution is to put satellites so high, that down is about the same to everyone (geostationary altitude). But then that takes 100 times more altitude, and that takes 10,000 times more power. Better to just live with the laws of physics... I guess. Bob, WB4aPR On Sat, Aug 4, 2012 at 2:47 PM, Bob Bruninga bruni...@usna.edu wrote: I believe that is true but that does not explain why the optimum polarity setting on the receive end would change during a pass. That's easy. The circularity on a pair of crossed dipoles (about all you can get on a spacecraft) May be designed for Right hand circularity when viewed from the prime direction. But by definition, that save waveform will be LHC when viewed from the opposite direction. And since the geometry to any one observer is constantly changing by almost 180 degrees during an overhead pass, that is why it is very easy to see, complete change in circularity. Bob, WB4APR -- Sent from my computer. tom ... ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
On 5/24/2012 9:15 PM, Bob Bruninga wrote: all the RS rotators are 110v with no 12v option I'd hate to use an inverter just for that, But a 100W inverter that plugs into a cigarette lighter is only $24 or less at Walmart. That is much less than you would pay compared to trying to find a 12v rotator system. I agree. I have built a couple of 12V satellite tracker servo systems, and the cost is too high in small quantities to ignore the efficacy of the inverter solution. Please visit http://www.lostfrogs.com/SatTrack.htm . My first system was in the AMSAT newsletter of July/August 2009. That system worked OK, but my last system was much improved with dual antennas and by beefier motors and gearing, and was used to make numerous contacts during the 2010 Field Day. I sold that system to a eager Satellite Ham for $400; that included hand made gear boxes and supported by the Parallax BASIC Stamp. I broke even in materials, that is all. My current plans are for an improved system (in terms of speeds and accel/decel issues) based upon the Parallax Propeller. As a hobbyist I will buy what I need to put the system together, but if someone is interested in funding an endeavor I am open to that prospect! Incidentally the inverter problems are maybe less than the RF into the servo controller problems, hence the 8' boom in the current version to get greater distance from the antennas and the servos. Dave KI4PSR On 5/24/2012 9:15 PM, Bob Bruninga wrote: all the RS rotators are 110v with no 12v option I'd hate to use an inverter just for that, But a 100W inverter that plugs into a cigarette lighter is only $24 or less at Walmart. That is much less than you would pay compared to trying to find a 12v rotator system. I had similar designs for 12v rotator systems, but just got lazy and realized it is easier to simply use these cheap inverters that are 95% efficient and just use whatever I need in the car for playing ham radio wether it is 12v or 115v, dosn't matter. Though watch for RFI from the inverter? Bob, Wb4APR Ted wrote: Lee, there is a construction article in Chap 6 of the ARRL Satellite Handbook (too complicated for me) But the reality is that it is easy to manually turn the RS rotor with the control box from the comfort of your chair just following the azimuth showing on your sat program and listening with your ear...this will get you close enough. I have the Elk on a RS rotor with Bob's fixed elevation. (Worked good enough for VUCC #226) Of course, the original question was about mobile installation, so unless you have a long extension cord or a generator... hi hi 73, Ted, K7TRK ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
Lee, I have yet to find a better solution for FO-29, SO-50, and AO-27 mobile than a combination of small UHF yagi with preamp for the downlink and a VHF vertical for the uplink. While the quadrifilar helix, eggbeaters, and 19 whip all work, nothing gives me a 100% copy of all the LEO's from AOS to LOS like the yagi/preamp combination. I've tested the above mentioned fixed antennas for downlink across a variety of Texas terrain and surrounding noise environments. They all work, some better than others, but are no where near the performance level of a directional antenna. Since I'm a firm believer that hearing the bird is #1, I do not compromise with a vertical. It's safer for me to pull my vehicle over to a parking lot or rest area to work passes. I have done a few passes in motion with both the quad and the 19 whip and quite frankly terrain/obstructions play such a huge role I hardly recommend even attempting to do it unless you are on a flat, high plain. 73 Clayton W5PFG On Thu, May 24, 2012 at 3:02 AM, Lee Maisel mai...@lobo.net wrote: Any ideas on a good antenna combo for mounting on a large vehicle? Possibly roofrack, specifically for satellite work? Thanks! Lee W5LMM __**_ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/**listinfo/amsat-bbhttp://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
Thanks Clayton! Now if I could find a small commercial az-el rotator for an Arrow, that would be ideal! Lee Clayton Coleman W5PFG wrote: Lee, I have yet to find a better solution for FO-29, SO-50, and AO-27 mobile than a combination of small UHF yagi with preamp for the downlink and a VHF vertical for the uplink. While the quadrifilar helix, eggbeaters, and 19 whip all work, nothing gives me a 100% copy of all the LEO's from AOS to LOS like the yagi/preamp combination. I've tested the above mentioned fixed antennas for downlink across a variety of Texas terrain and surrounding noise environments. They all work, some better than others, but are no where near the performance level of a directional antenna. Since I'm a firm believer that hearing the bird is #1, I do not compromise with a vertical. It's safer for me to pull my vehicle over to a parking lot or rest area to work passes. I have done a few passes in motion with both the quad and the 19 whip and quite frankly terrain/obstructions play such a huge role I hardly recommend even attempting to do it unless you are on a flat, high plain. 73 Clayton W5PFG On Thu, May 24, 2012 at 3:02 AM, Lee Maisel mai...@lobo.net mailto:mai...@lobo.net wrote: Any ideas on a good antenna combo for mounting on a large vehicle? Possibly roofrack, specifically for satellite work? Thanks! Lee W5LMM ___ Sent via AMSAT-BB@amsat.org mailto:AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
The company that comes out with an AZ/EL unit that is about $200 is going to sell a million. - Original Message - From: Lee Maisel mai...@lobo.net To: amsat-bb amsat-bb@amsat.org Sent: Thursday, May 24, 2012 1:02:39 PM Subject: [amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work. Thanks Clayton! Now if I could find a small commercial az-el rotator for an Arrow, that would be ideal! Lee Clayton Coleman W5PFG wrote: Lee, I have yet to find a better solution for FO-29, SO-50, and AO-27 mobile than a combination of small UHF yagi with preamp for the downlink and a VHF vertical for the uplink. While the quadrifilar helix, eggbeaters, and 19 whip all work, nothing gives me a 100% copy of all the LEO's from AOS to LOS like the yagi/preamp combination. I've tested the above mentioned fixed antennas for downlink across a variety of Texas terrain and surrounding noise environments. They all work, some better than others, but are no where near the performance level of a directional antenna. Since I'm a firm believer that hearing the bird is #1, I do not compromise with a vertical. It's safer for me to pull my vehicle over to a parking lot or rest area to work passes. I have done a few passes in motion with both the quad and the 19 whip and quite frankly terrain/obstructions play such a huge role I hardly recommend even attempting to do it unless you are on a flat, high plain. 73 Clayton W5PFG On Thu, May 24, 2012 at 3:02 AM, Lee Maisel mai...@lobo.net mailto:mai...@lobo.net wrote: Any ideas on a good antenna combo for mounting on a large vehicle? Possibly roofrack, specifically for satellite work? Thanks! Lee W5LMM ___ Sent via AMSAT-BB@amsat.org mailto:AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
The company that comes out with an AZ/EL unit that is about $200 is going to sell a million. Radioshack already does. Its called a TV rotator, and I would buy one before they are no more!. For LEO satellites one does not need elevation 98% of the time and with a modest beam (ARROW type) you can have a $70 system. Tilt the beam up about 15 degrees so that you still have max gain on the horizon where satellites spend 1/3rd of all their pass times below 20 degrees. Track then in AZ only. As the satellite gets above about 30 degrees and starts to roll off a dB or so of beam gain, remember that at that elevation the satellite is HALF as far away so it is now 6 dB stronger! This remains true up to over 45 degrees, where you may be down 3 dB on the beam but the signal is 10 dB closer to you! The break-even point is above about 70 degrees. BUT! Remember, the satellite is only above 70 degrees less than 2% of all pass times. Simply not worth spending another $700 for an elevation rotator for 1 minute a day of better access. Also, do NOT be tempted to tilt above about 15 degrees or you are going to lose gain on the horizon where you need it most. Lots of folks put it up higher because it seems logical, but they are ignoring the very significant DISTANCE factor at low elevations (sketched to scale on the web page). Please take a look at the plots on http://aprs.org/rotator1.html Its an old page, but the drawings are always valid. Bob, WB4APR - Original Message - From: Lee Maisel mai...@lobo.net To: amsat-bb amsat-bb@amsat.org Sent: Thursday, May 24, 2012 1:02:39 PM Subject: [amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work. Thanks Clayton! Now if I could find a small commercial az-el rotator for an Arrow, that would be ideal! Lee Clayton Coleman W5PFG wrote: Lee, I have yet to find a better solution for FO-29, SO-50, and AO-27 mobile than a combination of small UHF yagi with preamp for the downlink and a VHF vertical for the uplink. While the quadrifilar helix, eggbeaters, and 19 whip all work, nothing gives me a 100% copy of all the LEO's from AOS to LOS like the yagi/preamp combination. I've tested the above mentioned fixed antennas for downlink across a variety of Texas terrain and surrounding noise environments. They all work, some better than others, but are no where near the performance level of a directional antenna. Since I'm a firm believer that hearing the bird is #1, I do not compromise with a vertical. It's safer for me to pull my vehicle over to a parking lot or rest area to work passes. I have done a few passes in motion with both the quad and the 19 whip and quite frankly terrain/obstructions play such a huge role I hardly recommend even attempting to do it unless you are on a flat, high plain. 73 Clayton W5PFG On Thu, May 24, 2012 at 3:02 AM, Lee Maisel mai...@lobo.net mailto:mai...@lobo.net wrote: Any ideas on a good antenna combo for mounting on a large vehicle? Possibly roofrack, specifically for satellite work? Thanks! Lee W5LMM ___ Sent via AMSAT-BB@amsat.org mailto:AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
I completely agree with that statement. I'm sure there are enough smart fellers here that we can all get together and develop one. Lee W5LMM k4...@comcast.net wrote: The company that comes out with an AZ/EL unit that is about $200 is going to sell a million. *From: *Lee Maisel mai...@lobo.net *To: *amsat-bb amsat-bb@amsat.org *Sent: *Thursday, May 24, 2012 1:02:39 PM *Subject: *[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work. Thanks Clayton! Now if I could find a small commercial az-el rotator for an Arrow, that would be ideal! Lee ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
Thanks Bob That is extremely helpful, and most likely what I will do. Now, is there a computer interface somewhere for these RS rotators? Lee W5LMM Bob Bruninga wrote: The company that comes out with an AZ/EL unit that is about $200 is going to sell a million. Radioshack already does. Its called a TV rotator, and I would buy one before they are no more!. For LEO satellites one does not need elevation 98% of the time and with a modest beam (ARROW type) you can have a $70 system. Tilt the beam up about 15 degrees so that you still have max gain on the horizon where satellites spend 1/3rd of all their pass times below 20 degrees. Track then in AZ only. As the satellite gets above about 30 degrees and starts to roll off a dB or so of beam gain, remember that at that elevation the satellite is HALF as far away so it is now 6 dB stronger! This remains true up to over 45 degrees, where you may be down 3 dB on the beam but the signal is 10 dB closer to you! The break-even point is above about 70 degrees. BUT! Remember, the satellite is only above 70 degrees less than 2% of all pass times. Simply not worth spending another $700 for an elevation rotator for 1 minute a day of better access. Also, do NOT be tempted to tilt above about 15 degrees or you are going to lose gain on the horizon where you need it most. Lots of folks put it up higher because it seems logical, but they are ignoring the very significant DISTANCE factor at low elevations (sketched to scale on the web page). Please take a look at the plots on http://aprs.org/rotator1.html Its an old page, but the drawings are always valid. Bob, WB4APR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work.
Lee, there is a construction article in Chap 6 of the ARRL Satellite Handbook (too complicated for me) But the reality is that it is easy to manually turn the RS rotor with the control box from the comfort of your chair just following the azimuth showing on your sat program and listening with your ear...this will get you close enough. I have the Elk on a RS rotor with Bob's fixed elevation. (Worked good enough for VUCC #226) Of course, the original question was about mobile installation, so unless you have a long extension cord or a generator... hi hi 73, Ted, K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Lee Maisel Sent: Thursday, May 24, 2012 1:00 PM To: Bob Bruninga; amsat-bb Subject: [amsat-bb] Re: Antenna suggestions for mounting on vehicle for sat work. Thanks Bob That is extremely helpful, and most likely what I will do. Now, is there a computer interface somewhere for these RS rotators? Lee W5LMM Bob Bruninga wrote: The company that comes out with an AZ/EL unit that is about $200 is going to sell a million. Radioshack already does. Its called a TV rotator, and I would buy one before they are no more!. For LEO satellites one does not need elevation 98% of the time and with a modest beam (ARROW type) you can have a $70 system. Tilt the beam up about 15 degrees so that you still have max gain on the horizon where satellites spend 1/3rd of all their pass times below 20 degrees. Track then in AZ only. As the satellite gets above about 30 degrees and starts to roll off a dB or so of beam gain, remember that at that elevation the satellite is HALF as far away so it is now 6 dB stronger! This remains true up to over 45 degrees, where you may be down 3 dB on the beam but the signal is 10 dB closer to you! The break-even point is above about 70 degrees. BUT! Remember, the satellite is only above 70 degrees less than 2% of all pass times. Simply not worth spending another $700 for an elevation rotator for 1 minute a day of better access. Also, do NOT be tempted to tilt above about 15 degrees or you are going to lose gain on the horizon where you need it most. Lots of folks put it up higher because it seems logical, but they are ignoring the very significant DISTANCE factor at low elevations (sketched to scale on the web page). Please take a look at the plots on http://aprs.org/rotator1.html Its an old page, but the drawings are always valid. Bob, WB4APR ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna rotator test
very interesting question, I expected planty of answers. with my little experience, I use the sun for RF source and program which calculating elevation and azimuth. When you pointing to sun you can hear sun noise but you need to have wideband like ssb 2.4khz or AM. the better way is without AGC. I hope this is useful for you, any comments are welcome 73's AB On Tue, Aug 2, 2011 at 2:51 PM, N. Mahdinejad n.mahdine...@gmail.com wrote: DAER AMSAT members. Is there anyone who has information about pointing accuracy test procedure of parabolic antenna controllers? Could you please send me some links or book names or papers those describe the procedure of testing pointing accuracy of for e.g. 2 or 3 m antenna controllers. Any help would be gratefully appreciated. Best Regards. N.Mahdinejad ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna rotator test
- Original Message - From: N. Mahdinejad n.mahdine...@gmail.com To: amsat-bb@amsat.org Sent: Tuesday, August 02, 2011 2:51 PM Subject: [amsat-bb] antenna rotator test DAER AMSAT members. Is there anyone who has information about pointing accuracy test procedure of parabolic antenna controllers? Could you please send me some links or book names or papers those describe the procedure of testing pointing accuracy of for e.g. 2 or 3 m antenna controllers. Any help would be gratefully appreciated. Best Regards. N.Mahdinejad ___ Hi, N.Mahdinejad You don't mention the frequency used for your 2 or 3 meter dish. By the way the best procedure to test the point accuracy for a 2 or 3 meter dish is to receive the Sun Noise at the frequency of operation. Using any satellite traking program you can compute the azimuth and elevation of the Sun for a particular time and then chek if you receive the strongest Sun Noise in the same azimut and elevation indicated by the satellite traking program. If the maximum Sun Noise do not match with the pointing of your dish than move mechanically the orientation of yor dish in order to get the maximum Sun Noise at that specific time of dish pointing adjustement. 73 de i8CVS Domenico ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions
Agree !! Along those lines, before I put up my Kenpro az/el rotor, I plan on testing various locations using my Elk with a fixed el but on a small rat shack rotor for az. I have seen here recommendations for 15 deg and some for 30 deg fixed el. Thus there seems to be 2 schools of thought on this. Is there any compelling argument for one or the other? I'm almost inclined to split the diff at +-22 deg. (most passes for me are N/S and to the E - not so good to W Any thoughts appreciated 73, Ted, K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of gw1...@aol.com Sent: Saturday, March 19, 2011 2:36 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions Hi all, Regarding the discussions on antennas - I am not into any debate about the pro's and con's, but would just like to encourage anyone to just have a go. Sure the argument will always prevail perhaps under the Must do Better comment and I am sure that one can always improve or progress with experimenting - ( AMATEUR RADIO ) ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions
The actual fixed elevation on the AZ rotor is determined by the beam width of the yagi antenna used. If at all possible, all the calculations based on the average pass elevation is near 30 degrees. If you believe that you will use lower passes, say if the beam width is 25 degrees, putting it fixed at about 20degrees gives you the split of + - 12.5 degrees. It IS a tradeoff. The higher the gain of the Yagi, the lower the beam width. Good Luck... Dee, NB2F -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Ted Sent: Thursday, March 24, 2011 2:02 PM To: gw1...@aol.com; amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions Agree !! Along those lines, before I put up my Kenpro az/el rotor, I plan on testing various locations using my Elk with a fixed el but on a small rat shack rotor for az. I have seen here recommendations for 15 deg and some for 30 deg fixed el. Thus there seems to be 2 schools of thought on this. Is there any compelling argument for one or the other? I'm almost inclined to split the diff at +-22 deg. (most passes for me are N/S and to the E - not so good to W Any thoughts appreciated 73, Ted, K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of gw1...@aol.com Sent: Saturday, March 19, 2011 2:36 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions Hi all, Regarding the discussions on antennas - I am not into any debate about the pro's and con's, but would just like to encourage anyone to just have a go. Sure the argument will always prevail perhaps under the Must do Better comment and I am sure that one can always improve or progress with experimenting - ( AMATEUR RADIO ) ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions
I agree with Dee, but I'll add my opinion. The fixed elevation option is a good approach to reduce your costs. If you are going to fix the elevation, do *not* use a very high gain antenna with a narrow beam width. You are better off with a moderate gain antenna (for example, the Elk or 4-7 element vertical or 2x7 circularly polarized) so that you have a wider beam width. 73, Steve N9IP -- Steve Belter (s...@wintek.com) My Desk: 765-269-8521 Indiana Dataline Corp Billing: 765-269-8502 427 N 6th Street, Suite C Wintek Internet: 765-269-8503 Lafayette, IN 47901-2211Wintek Consulting: 765-269-8504 -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb- boun...@amsat.org] On Behalf Of Dee Sent: Thursday, March 24, 2011 2:18 PM To: 'Ted'; gw1...@aol.com; amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions The actual fixed elevation on the AZ rotor is determined by the beam width of the yagi antenna used. If at all possible, all the calculations based on the average pass elevation is near 30 degrees. If you believe that you will use lower passes, say if the beam width is 25 degrees, putting it fixed at about 20degrees gives you the split of + - 12.5 degrees. It IS a tradeoff. The higher the gain of the Yagi, the lower the beam width. Good Luck... Dee, NB2F -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb- boun...@amsat.org] On Behalf Of Ted Sent: Thursday, March 24, 2011 2:02 PM To: gw1...@aol.com; amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions Agree !! Along those lines, before I put up my Kenpro az/el rotor, I plan on testing various locations using my Elk with a fixed el but on a small rat shack rotor for az. I have seen here recommendations for 15 deg and some for 30 deg fixed el. Thus there seems to be 2 schools of thought on this. Is there any compelling argument for one or the other? I'm almost inclined to split the diff at +-22 deg. (most passes for me are N/S and to the E - not so good to W Any thoughts appreciated 73, Ted, K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb- boun...@amsat.org] On Behalf Of gw1...@aol.com Sent: Saturday, March 19, 2011 2:36 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna discussions Hi all, Regarding the discussions on antennas - I am not into any debate about the pro's and con's, but would just like to encourage anyone to just have a go. Sure the argument will always prevail perhaps under the Must do Better comment and I am sure that one can always improve or progress with experimenting - ( AMATEUR RADIO ) ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions
I really forget was it the radio or the antenna that came first? ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions
Ted, How about a 3rd school of thought? If you have a clear view of the horizon, I recommend you point the antenna(s) directly at the antenna (0 degrees elevation). That is the point in a satellite's path across the sky where you have the greatest range (distance between you and the satellite) and the bi-directional greatest path loss (not counting any ground gain you will experience if you have horizontal or CP antennas). As the satellite rises in elevation, range and path loss both decrease and you need less gain to overcome noise: a moderate-beamwidth antenna with a gain of 8-10 dBi will match this nicely. A LEO satellite spends the majority of it's visible time below 30 degrees and the pass time above 60 degrees is almost negligible. If you can't hear the satellite at the horizon with this setup, then you can raise the antenna's angle and listen when the satellite is closer (higher elevation), but you will greatly reduce the available time/footprint and your number of contacts. 73, Jerry, K5OE -Original Message- Agree !! Along those lines, before I put up my Kenpro az/el rotor, I plan on testing various locations using my Elk with a fixed el but on a small rat shack rotor for az. I have seen here recommendations for 15 deg and some for 30 deg fixed el. Thus there seems to be 2 schools of thought on this. Is there any compelling argument for one or the other? I'm almost inclined to split the diff at +-22 deg. (most passes for me are N/S and to the E - not so good to W Any thoughts appreciated 73, Ted, K7TRK ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna discussions,
Back in the goode olde dayes, if we didn't have an elevation rotor we would put a horizontally polarized yagi at a fixed 30 degree elevation. That allowed working the satellites for at least 95 percent of a pass and often for a complete pass. I did this for quite a while before I obtained a rotor for controlling the elevation. Glen, K9STH AMSAT 239 / LM 463 Website: http://k9sth.com --- On Sat, 3/19/11, Ellis Foley wa1...@yahoo.com wrote: Like so many before me posted, I have had gud success with linear polarized antennas. I have been using stacked 11 el vertically pol, on 2m since 1974, and recently went to 2x20 el on 432-435 mhz horizontally pol, stacked in between the vertical 2m ant, With great success. as most of you that posted have worked me on them. fixed elevation also. from 0-30 deg. off the horizons I do very well, little spotty over head, although I do need some pre-amps to work the fm birds. but I think thats more of an radio problelm than antenna. my 2 cents worth! Pics of my ant. on my QRZ spot,along with the Beast my new HB 9el 36ft boom 6m ant. ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ-269 was purchased as new but connecting to it a professional 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz was 1.1 I have sent back my MFJ to the factory for inspecting and calibration but I belive that the above instrument was a very bad affair for me and will be a bad affair for all that intend to use the analyser above 30 MHz. Be happy with your MFJ-269 even if dreaming while sleeping I am sure that my message made you suspect a wrong real part and a wrong imaginary part on your impedance reading ! Best 73 de i8CVS Domenico - Original Message - From: Pete Rowe ptr...@yahoo.com To: AMSAT BB amsat-bb@amsat.org; Howard Kowall hkow...@shaw.ca Sent: Sunday, March 06, 2011 4:45 PM Subject: [amsat-bb] Re: Antenna Analyzer Hi Howard I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy size. Highly recommended. (no, I don't own stock in MFJ) One word of caution: mine (and maybe there is something wrong with mine) draws some power from the batteries with the power switch OFF. So I take one of the batteries out when not in use. 73, Pete WA6WOA --- On Sun, 3/6/11, Howard Kowall hkow...@shaw.ca wrote: From: Howard Kowall hkow...@shaw.ca Subject: [amsat-bb] Antenna Analyzer To: AMSAT BB amsat-bb@amsat.org Date: Sunday, March 6, 2011, 6:16 AM Hello to everyone I am seriously thinking about buying an antenna analyzer,I build enough antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all flavors.The standard swr bridge is just not cutting it anymore.So I guess what I am looking for is one that will do 3mhz to 500mhz,nice to have computer interface but not a priority.I have seen a few on the internet but its nice to get some user input,rather then the sales pitches. Thanks to all who read and reply in advance Howard VE4ISP ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
Thanks Dominico I have also compared my unit with an HP network analyzer and have found the readings to be quite acceptable for amateur work. Mine reads 1.0 :1 into a precision load up to 170 MHz. Indeed, it reads 1.1:1 at UHF and that is just fine for my measurements. Rarely do I see an antenna match less than 1.1:1. 73, Pete --- On Sun, 3/6/11, i8cvs domenico.i8...@tin.it wrote: From: i8cvs domenico.i8...@tin.it Subject: Re: [amsat-bb] Re: Antenna Analyzer To: Pete Rowe ptr...@yahoo.com, AMSAT BB amsat-bb@amsat.org, Howard Kowall hkow...@shaw.ca Date: Sunday, March 6, 2011, 9:40 AM Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ-269 was purchased as new but connecting to it a professional 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz was 1.1 I have sent back my MFJ to the factory for inspecting and calibration but I belive that the above instrument was a very bad affair for me and will be a bad affair for all that intend to use the analyser above 30 MHz. Be happy with your MFJ-269 even if dreaming while sleeping I am sure that my message made you suspect a wrong real part and a wrong imaginary part on your impedance reading ! Best 73 de i8CVS Domenico - Original Message - From: Pete Rowe ptr...@yahoo.com To: AMSAT BB amsat-bb@amsat.org; Howard Kowall hkow...@shaw.ca Sent: Sunday, March 06, 2011 4:45 PM Subject: [amsat-bb] Re: Antenna Analyzer Hi Howard I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy size. Highly recommended. (no, I don't own stock in MFJ) One word of caution: mine (and maybe there is something wrong with mine) draws some power from the batteries with the power switch OFF. So I take one of the batteries out when not in use. 73, Pete WA6WOA --- On Sun, 3/6/11, Howard Kowall hkow...@shaw.ca wrote: From: Howard Kowall hkow...@shaw.ca Subject: [amsat-bb] Antenna Analyzer To: AMSAT BB amsat-bb@amsat.org Date: Sunday, March 6, 2011, 6:16 AM Hello to everyone I am seriously thinking about buying an antenna analyzer,I build enough antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all flavors.The standard swr bridge is just not cutting it anymore.So I guess what I am looking for is one that will do 3mhz to 500mhz,nice to have computer interface but not a priority.I have seen a few on the internet but its nice to get some user input,rather then the sales pitches. Thanks to all who read and reply in advance Howard VE4ISP ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
First, befriend a Motorola technician at your local Moto dealership - if you haven't already. And you really have two price-point options: about US$400 for an MFJ-269, or a true piece of bench service gear at about US$5000. If you get an MFJ-269, use your contact with a real service tech to compare results. There was an issue with QC on the MFJ-269 (SOURCE: Personal experience, as I sold them for a couple of years). So - if you get a good one - or one with consistent results, you'll really enjoy it. Clint, K6LCS 909-241-7666 ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
Hi Art, KC6UQH If you are satisfied with an antenna VSWR in the order of 1.5 : 1 then you don't need an antenna analyser but only a VSWR meter. An antenna analyser must be able to measure with accuracy the real part and the imaginary part of the impedance i.e. the resistive and the reactive part of the impedance Z = R +/- jX For example the same antenna VSWR of 1.5 : 1 can be obtained with an antenna impedance having the following values and all of them are laying over the same VSWR circle of the Smith Chart Z1 = 38+j13 ohm Z2 = 66+j16 ohm Z3 = 58- j20 ohm Z4 = 34- j0 ohm Since the same VSWR can be found over a VSWR circle then the values of the impedance giving the same VSWR are infinite values. The MFJ-269 analyser make acceptable R +/-jX measurements only up to 30 MHz but fail to measure accurate resistive and reactive part of the impedance above 30 MHz and in other words it is not a respectable antenna analyser. Why to wast money to buy an antenna analyser to measure wrong values of Z= R+/- jX if been happy with only the value of the VSWR you need only a VSWR meter ? 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'i8cvs' domenico.i8...@tin.it; 'Pete Rowe' ptr...@yahoo.com; 'AMSAT BB' amsat-bb@amsat.org; 'Howard Kowall' hkow...@shaw.ca Sent: Sunday, March 06, 2011 7:38 PM Subject: RE: [amsat-bb] Re: Antenna Analyzer Domenico, For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have never expected MFJ products to be in the League of Anristu, HP and Rohde and Swartz. MFJ is a yard stick, the others are a micrometers Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of i8cvs Sent: Sunday, March 06, 2011 9:41 AM To: Pete Rowe; AMSAT BB; Howard Kowall Subject: [amsat-bb] Re: Antenna Analyzer Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ-269 was purchased as new but connecting to it a professional 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz was 1.1 I have sent back my MFJ to the factory for inspecting and calibration but I belive that the above instrument was a very bad affair for me and will be a bad affair for all that intend to use the analyser above 30 MHz. Be happy with your MFJ-269 even if dreaming while sleeping I am sure that my message made you suspect a wrong real part and a wrong imaginary part on your impedance reading ! Best 73 de i8CVS Domenico - Original Message - From: Pete Rowe ptr...@yahoo.com To: AMSAT BB amsat-bb@amsat.org; Howard Kowall hkow...@shaw.ca Sent: Sunday, March 06, 2011 4:45 PM Subject: [amsat-bb] Re: Antenna Analyzer Hi Howard I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy size. Highly recommended. (no, I don't own stock in MFJ) One word of caution: mine (and maybe there is something wrong with mine) draws some power from the batteries with the power switch OFF. So I take one of the batteries out when not in use. 73, Pete WA6WOA --- On Sun, 3/6/11, Howard Kowall hkow...@shaw.ca wrote: From: Howard Kowall hkow...@shaw.ca Subject: [amsat-bb] Antenna Analyzer To: AMSAT BB amsat-bb@amsat.org Date: Sunday, March 6, 2011, 6:16 AM Hello to everyone I am seriously thinking about buying an antenna analyzer,I build enough antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all flavors.The standard swr bridge is just not cutting it anymore.So I guess what I am looking for is one that will do 3mhz to 500mhz,nice to have computer interface but not a priority.I have seen a few on the internet but its nice to get some user input,rather then the sales pitches. Thanks to all who read and reply in advance Howard VE4ISP ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb __ Information from ESET NOD32 Antivirus
[amsat-bb] Re: Antenna Analyzer
At 11:28 AM 3/6/2011, Clint Bradford wrote: First, befriend a Motorola technician at your local Moto dealership - if you haven't already. And you really have two price-point options: about US$400 for an MFJ-269, or a true piece of bench service gear at about US$5000. If you get an MFJ-269, use your contact with a real service tech to compare results. There was an issue with QC on the MFJ-269 (SOURCE: Personal experience, as I sold them for a couple of years). So - if you get a good one - or one with consistent results, you'll really enjoy it. Clint, K6LCS 909-241-7666 ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb I bought mine used on e-bay and spent too much for it. Failed the third day and cost me $70+shipping to get it fixed by MFJ. I ended up spending more than a brand new unit ;-) But is compares well with Bird43 measurements (which are 95% accurate) so good enough for ham use at my place. I modified mine to operate on LF for tuning loading coils on those short LF antennas. See my website under tech topics. I ran it on a 4AH gel-cell for a couple years until I got tired of lugging around the battery (installed ten NiMH AA cells and charge it with the bench PS). It is very handy for those quick checks of antennas or cables. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
Clint, There are a few units filling in that price range, fortunately much closer to MFJ than the Motorola in price. http://www.rigexpert.com/ http://www.w5big.com/ My MFJ-269 is great on HF, but even after calibration is problematical on VHF and up. I keep wanting to replace it, but having recently bought some new, expensive toys, can't justify something I don't use that often. Alan WA4SCA ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
Domenico, A. It is much smaller than MY H/P 8410 + 8414 + test set, sweep generator. B. It will tell me if the resistive arm is above or below 50 Ohms. C. It will give me the reactance Vs frequency with in 10 ohms. D. It is battery operated, portable, and can be used on a tower. E. It costs less than a 1 month rental of a quality Network Analyzer. F. A VSWR measurement will not separate the resistive and reactive arms G. When tuning an antenna you never start at 1.5 :1!If it is that good there is no need to tune it. 73, Art, KC6UQH -Original Message- From: i8cvs [mailto:domenico.i8...@tin.it] Sent: Sunday, March 06, 2011 12:30 PM To: kc6...@cox.net; 'Pete Rowe'; 'AMSAT BB'; 'Howard Kowall' Subject: Re: [amsat-bb] Re: Antenna Analyzer Hi Art, KC6UQH If you are satisfied with an antenna VSWR in the order of 1.5 : 1 then you don't need an antenna analyser but only a VSWR meter. An antenna analyser must be able to measure with accuracy the real part and the imaginary part of the impedance i.e. the resistive and the reactive part of the impedance Z = R +/- jX For example the same antenna VSWR of 1.5 : 1 can be obtained with an antenna impedance having the following values and all of them are laying over the same VSWR circle of the Smith Chart Z1 = 38+j13 ohm Z2 = 66+j16 ohm Z3 = 58- j20 ohm Z4 = 34- j0 ohm Since the same VSWR can be found over a VSWR circle then the values of the impedance giving the same VSWR are infinite values. The MFJ-269 analyser make acceptable R +/-jX measurements only up to 30 MHz but fail to measure accurate resistive and reactive part of the impedance above 30 MHz and in other words it is not a respectable antenna analyser. Why to wast money to buy an antenna analyser to measure wrong values of Z= R+/- jX if been happy with only the value of the VSWR you need only a VSWR meter ? 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'i8cvs' domenico.i8...@tin.it; 'Pete Rowe' ptr...@yahoo.com; 'AMSAT BB' amsat-bb@amsat.org; 'Howard Kowall' hkow...@shaw.ca Sent: Sunday, March 06, 2011 7:38 PM Subject: RE: [amsat-bb] Re: Antenna Analyzer Domenico, For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have never expected MFJ products to be in the League of Anristu, HP and Rohde and Swartz. MFJ is a yard stick, the others are a micrometers Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of i8cvs Sent: Sunday, March 06, 2011 9:41 AM To: Pete Rowe; AMSAT BB; Howard Kowall Subject: [amsat-bb] Re: Antenna Analyzer Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ-269 was purchased as new but connecting to it a professional 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz was 1.1 I have sent back my MFJ to the factory for inspecting and calibration but I belive that the above instrument was a very bad affair for me and will be a bad affair for all that intend to use the analyser above 30 MHz. Be happy with your MFJ-269 even if dreaming while sleeping I am sure that my message made you suspect a wrong real part and a wrong imaginary part on your impedance reading ! Best 73 de i8CVS Domenico - Original Message - From: Pete Rowe ptr...@yahoo.com To: AMSAT BB amsat-bb@amsat.org; Howard Kowall hkow...@shaw.ca Sent: Sunday, March 06, 2011 4:45 PM Subject: [amsat-bb] Re: Antenna Analyzer Hi Howard I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy size. Highly recommended. (no, I don't own stock in MFJ) One word of caution: mine (and maybe there is something wrong with mine) draws some power from the batteries with the power switch OFF. So I take one of the batteries out when not in use. 73, Pete WA6WOA --- On Sun, 3/6/11, Howard Kowall hkow...@shaw.ca wrote: From: Howard Kowall hkow...@shaw.ca Subject: [amsat-bb] Antenna Analyzer To: AMSAT BB amsat-bb@amsat.org Date: Sunday, March 6, 2011, 6:16 AM Hello to everyone I am seriously thinking about buying an antenna analyzer,I build enough antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all flavors.The standard swr bridge is just not cutting it anymore.So I guess what I am looking for is one that will do 3mhz to 500mhz,nice to have computer interface but not a priority.I have seen a few on the internet but its nice to get some user input,rather then the sales pitches. Thanks to all who read and reply in advance Howard VE4ISP ___ Sent via AMSAT-BB@amsat.org. Opinions
[amsat-bb] Re: Antenna Analyzer
Hi Art, KC6UQH If you are satisfied with an antenna VSWR in the order of 1.5 : 1 then you don't need an antenna analyser but only a VSWR meter. An antenna analyser must be able to measure with accuracy the real part and the imaginary part of the impedance i.e. the resistive and the reactive part of the impedance Z = R +/- jX For example the same antenna VSWR of 1.5 : 1 can be obtained with an antenna impedance having the following values and all of them are laying over the same VSWR circle of the Smith Chart Z1 = 38+j13 ohm Z2 = 66+j16 ohm Z3 = 58- j20 ohm Z4 = 34- j0 ohm Since the same VSWR can be found over a VSWR circle then the values of the impedance giving the same VSWR are infinite values. The MFJ-269 analyser make acceptable R +/-jX measurements only up to 30 MHz but fail to measure accurate resistive and reactive part of the impedance above 30 MHz and in other words it is not a respectable antenna analyser. Why to wast money to buy an antenna analyser to measure wrong values of Z= R+/- jX if been happy with only the value of the VSWR you need only a VSWR meter ? 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'i8cvs' domenico.i8...@tin.it; 'Pete Rowe' ptr...@yahoo.com; 'AMSAT BB' amsat-bb@amsat.org; 'Howard Kowall' hkow...@shaw.ca Sent: Sunday, March 06, 2011 7:38 PM Subject: RE: [amsat-bb] Re: Antenna Analyzer Domenico, For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have never expected MFJ products to be in the League of Anristu, HP and Rohde and Swartz. MFJ is a yard stick, the others are a micrometers Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of i8cvs Sent: Sunday, March 06, 2011 9:41 AM To: Pete Rowe; AMSAT BB; Howard Kowall Subject: [amsat-bb] Re: Antenna Analyzer Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ-269 was purchased as new but connecting to it a professional 50 ohm termination good up to 12 GHz the VSWR shown at 435 MHz was 1.1 I have sent back my MFJ to the factory for inspecting and calibration but I belive that the above instrument was a very bad affair for me and will be a bad affair for all that intend to use the analyser above 30 MHz. Be happy with your MFJ-269 even if dreaming while sleeping I am sure that my message made you suspect a wrong real part and a wrong imaginary part on your impedance reading ! Best 73 de i8CVS Domenico - Original Message - From: Pete Rowe ptr...@yahoo.com To: AMSAT BB amsat-bb@amsat.org; Howard Kowall hkow...@shaw.ca Sent: Sunday, March 06, 2011 4:45 PM Subject: [amsat-bb] Re: Antenna Analyzer Hi Howard I wouldn't be without my MFJ-269 analyzer. It is very accurate and a handy size. Highly recommended. (no, I don't own stock in MFJ) One word of caution: mine (and maybe there is something wrong with mine) draws some power from the batteries with the power switch OFF. So I take one of the batteries out when not in use. 73, Pete WA6WOA --- On Sun, 3/6/11, Howard Kowall hkow...@shaw.ca wrote: From: Howard Kowall hkow...@shaw.ca Subject: [amsat-bb] Antenna Analyzer To: AMSAT BB amsat-bb@amsat.org Date: Sunday, March 6, 2011, 6:16 AM Hello to everyone I am seriously thinking about buying an antenna analyzer,I build enough antennas to justify buying one.I enjoy building HF,VHF,UHF antennas of all flavors.The standard swr bridge is just not cutting it anymore.So I guess what I am looking for is one that will do 3mhz to 500mhz,nice to have computer interface but not a priority.I have seen a few on the internet but its nice to get some user input,rather then the sales pitches. Thanks to all who read and reply in advance Howard VE4ISP ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Analyzer
- Original Message - From: Art McBride kc6...@cox.net To: 'i8cvs' domenico.i8...@tin.it; 'Pete Rowe' ptr...@yahoo.com; 'AMSAT BB' amsat-bb@amsat.org; 'Howard Kowall' hkow...@shaw.ca Sent: Monday, March 07, 2011 2:38 AM Subject: RE: [amsat-bb] Re: Antenna Analyzer Domenico, A. It is much smaller than MY H/P 8410 + 8414 + test set, sweep generator. Hi Art, KC6UQH I agree that the MFJ-269 is smaller than your above banch set-up B. It will tell me if the resistive arm is above or below 50 Ohms. Only it tell you the resistive part R of the impedance up to 30 MHz but the instrument is sold to measure R up to 170 MHz C. It will give me the reactance Vs frequency with in 10 ohms. Only it tell you the inductive reactance +jX up to 30 MHz but the instrument is sold to measure +jX up to 170 MHz D. It is battery operated, portable, and can be used on a tower. When you are on the tower with your MFJ-269 you can adjust the antenna for the lovest VSWR only looking at the VSWR on display without exactly know Z = R+/-jX above 30 MHz and so a more simple VSWR meter does the same job. E. It costs less than a 1 month rental of a quality Network Analyzer. I agree F. A VSWR measurement will not separate the resistive and reactive arms I agree and this is why for a given VSWR we need an antenna analyser capable to measure the value of the resistive part R and the reactive part +jX or -jX of the impedance particularly when we are over the tower to adjust the matching system and cancel out the inductive or the capacitive part of the impedance. Using the MFJ-269 if you don't look at the VSWR but you look only at R and +jX or -jX being on the tower it is like to drive a car above 30 MHz without to know if rotating the wheel you will go to left or right on the road ! G. When tuning an antenna you never start at 1.5 :1!If it is that good there is no need to tune it. To tune an antenna you don't need mandatorily an antenna analyser but only you need a VSWR meter to move the maching arness for the lovest VSWR An antenna analyser is indeed needed only to cut or prolong in advance stubs and matching lines or antenna elements to get a matching as close as possible to 50 ohm resistive and 0 ohm reactive i.e to get an impedance as close as possible to Z = 50 + j0 ohm but unfortunately the MFJ-269 does satisfactorily this job only up to 30 MHz ! 73, Art, KC6UQH 73 de i8CVS Domenico -Original Message- From: i8cvs [mailto:domenico.i8...@tin.it] Sent: Sunday, March 06, 2011 12:30 PM To: kc6...@cox.net; 'Pete Rowe'; 'AMSAT BB'; 'Howard Kowall' Subject: Re: [amsat-bb] Re: Antenna Analyzer Hi Art, KC6UQH If you are satisfied with an antenna VSWR in the order of 1.5 : 1 then you don't need an antenna analyser but only a VSWR meter. An antenna analyser must be able to measure with accuracy the real part and the imaginary part of the impedance i.e. the resistive and the reactive part of the impedance Z = R +/- jX For example the same antenna VSWR of 1.5 : 1 can be obtained with an antenna impedance having the following values and all of them are laying over the same VSWR circle of the Smith Chart Z1 = 38+j13 ohm Z2 = 66+j16 ohm Z3 = 58- j20 ohm Z4 = 34- j0 ohm Since the same VSWR can be found over a VSWR circle then the values of the impedance giving the same VSWR are infinite values. The MFJ-269 analyser make acceptable R +/-jX measurements only up to 30 MHz but fail to measure accurate resistive and reactive part of the impedance above 30 MHz and in other words it is not a respectable antenna analyser. Why to wast money to buy an antenna analyser to measure wrong values of Z= R+/- jX if been happy with only the value of the VSWR you need only a VSWR meter ? 73 de i8CVS Domenico - Original Message - From: Art McBride kc6...@cox.net To: 'i8cvs' domenico.i8...@tin.it; 'Pete Rowe' ptr...@yahoo.com; 'AMSAT BB' amsat-bb@amsat.org; 'Howard Kowall' hkow...@shaw.ca Sent: Sunday, March 06, 2011 7:38 PM Subject: RE: [amsat-bb] Re: Antenna Analyzer Domenico, For most Amateur Radio work a VSWR of 1.5:1 is adequate. I personally have never expected MFJ products to be in the League of Anristu, HP and Rohde and Swartz. MFJ is a yard stick, the others are a micrometers Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of i8cvs Sent: Sunday, March 06, 2011 9:41 AM To: Pete Rowe; AMSAT BB; Howard Kowall Subject: [amsat-bb] Re: Antenna Analyzer Hi Pete, WA6WOA I do not recommend the MFJ-269 antenna analyser because it is very inaccurate particularly on 435 MHz I have compared the MFJ-269 with several professional network analysers and I have found that at most the MFJ is usable up to 30 MHz maximum because above 30 MHz the inaccuracy on the real part and the imaginary part of the impedance reading becomes absolutely unacceptable. My MFJ
[amsat-bb] Re: Antenna Analyzer
In addition to the other alternatives described by WA4SCA, Let me also suggest another nice VNA (Vector Network Analyzer) -- the Mini-VNA and Mini-VNA PRO made in Europe and available in the US from http://www.w4rt.com/ and Gigaparts (http://www.gigaparts.com/gpsales/1002/store.php?action=profilesku=ZW4-MINIVNA http://www.gigaparts.com/gpsales/1002/store.php?action=profilesku=ZW4-MINIVNA and http://www.gigaparts.com/gpsales/1002/store.php?action=profilesku=ZW4-MINIVNA-PRO http://www.gigaparts.com/gpsales/1002/store.php?action=profilesku=ZW4-MINIVNA-PRO). I got my Mini-VNA PRO last year at Dayton from W4RT and I find it to be a most interesting widget. It is a full 2-port VNA covering the entire 0.1-200 MHz range. It is intended to be used with a Windoze computer (my Lenovo Netbook is more than adequate) and normally connects via USB. The USB port provides DC power, either to run the unit or to charge its internal LiPO battery. It is battery powered and can also interface via a wireless Bluetooth serial port. One nifty thing here -- you can put the entire VNA at the feedpoint of an antenna (very useful with an HF wire), hoist it into the air and measure the intrinsic feedpoint impedance with NO cables attached, making all measurements using the wireless Bluetooth connection. Another useful additional function is that the PRO has two independent DDS generators, one associated with each port. They can be programmed to use as separate programmable test oscillators. The Mini-VNA and PRO are of German origin and marketed by Wimo: http://www.wimo.com/cgi-bin/verteiler.pl?url=instrumentation_e.htmlp=minivna-more-e#minivna http://www.wimo.com/cgi-bin/verteiler.pl?url=instrumentation_e.htmlp=minivna-more-e#minivna. There is a nice writeup on the original Mini-VNA in the British magazine Practical Wireless (http://www.wimo.com/download/testreport_minivna_practical_wireless-dec-07.pdf) that describes use of the VNA. 73, Tom K3IO ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Observations/Question
a coat hanger will some what work also. But I really guess that age old saying of - you get what you pay for Best sums it up. In a Dirty Harry voice - do you want it to just work or work great? ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Observations/Question
Tnx to all for useful replies. I'm now going to do a bit more research before striking out to build something I haven't yet tried on the says - either quagie or moxon or both. Spring had to be coming! On Sunday, January 23, 2011, Rocky Jones orbit...@hotmail.com wrote: Rick. on the cheap antenna front I've tried and had pretty good success with two things. First there is a 5 element Yagi design that was published in QST that uses/modifies an Archer 5 element FM yagi. I built one and added some 70 cm elements 90 out of phase and thats worked great. My home QTH is in a bit of flux (we are moving to a farm out by Santa Fe Tx from my home QTH in Clear Lake TX) so I built another one, put them both on a boom 90 degrees out in an X configuration, stuck them at 33 degrees and they work well. I will keep them once we move into the perm QTH. I've also used the crossed dipoles and Lindenblad antenna from QST (not the AMSAT one) and they work great. I modified one for WX satellite reception and am very happy with them. I am in Nigeria now and have a modified Lindenblad for my WX station here but its copied really well most of the two meter Oscars including AO-7. I didnt have Nigerian operating authority when I left the states (but now have a five year license) so I didnt bring any transmit equipment...but from the roof of the Sheraton in Abuja the WX version works great. I've got permission to set up permanent antennas on the Sheraton and I will be back so am going to have some good operating here. I would upload pictures, but I tried to upload some of the really big HF array on the road to the airport and they never showed up...if you want some pictures of what I have at home I will be happy to send them to you. IN about two weeks! Robert G. Oler WB5MZO Life member Amsat/ARRL Date: Sun, 23 Jan 2011 12:47:10 -0500 From: rjl...@gmail.com To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Observations/Question I've been on the birds off an on for years. I have an M2 cir. polarized pair at home QTH and am looking into a more modest installation for a summer cottage. I've built the K5OE eggbeater imitations and founds them to be only fair.I could by M2 eggbeater pair but I'm trying to do this on less $. I also have an Arrow antenna which I've tried some with a HT with only fair results. Any other suggestions out there? Mount the Arrow more permanently but at a fixed elevation and use a simple rotor to change azimuth? How about a homebrewed quagi? Any suggestions appreciated. Rick W2JAZ ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Observations/Question
Hi Rick, I too tried the eggbeaters and found them worthless. Also tried a commercial made quadrifilar rx from antenna.us. then... In the ARRL Satellite Handbook found the Moxon turnstile for the LEOs. Being a fan of Moxons, I have built both the tx and rx and am quite please with performance over the past antennas. Built all from pvc and brass tubing from the hobby shop. You should be able to build both for less than _+ $25.00 and your junk box. The article is on the ARRL site or maybe search internet (Moxon turnstile antenna) I think this will fill your requirements GL, Ted K7TRK -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Richard Lawn Sent: Sunday, January 23, 2011 9:47 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Observations/Question I've been on the birds off an on for years. I have an M2 cir. polarized pair at home QTH and am looking into a more modest installation for a summer cottage. I've built the K5OE eggbeater imitations and founds them to be only fair.I could by M2 eggbeater pair but I'm trying to do this on less $. I also have an Arrow antenna which I've tried some with a HT with only fair results. Any other suggestions out there? Mount the Arrow more permanently but at a fixed elevation and use a simple rotor to change azimuth? How about a homebrewed quagi? Any suggestions appreciated. Rick W2JAZ ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Observations/Question
Rick. on the cheap antenna front I've tried and had pretty good success with two things. First there is a 5 element Yagi design that was published in QST that uses/modifies an Archer 5 element FM yagi. I built one and added some 70 cm elements 90 out of phase and thats worked great. My home QTH is in a bit of flux (we are moving to a farm out by Santa Fe Tx from my home QTH in Clear Lake TX) so I built another one, put them both on a boom 90 degrees out in an X configuration, stuck them at 33 degrees and they work well. I will keep them once we move into the perm QTH. I've also used the crossed dipoles and Lindenblad antenna from QST (not the AMSAT one) and they work great. I modified one for WX satellite reception and am very happy with them. I am in Nigeria now and have a modified Lindenblad for my WX station here but its copied really well most of the two meter Oscars including AO-7. I didnt have Nigerian operating authority when I left the states (but now have a five year license) so I didnt bring any transmit equipment...but from the roof of the Sheraton in Abuja the WX version works great. I've got permission to set up permanent antennas on the Sheraton and I will be back so am going to have some good operating here. I would upload pictures, but I tried to upload some of the really big HF array on the road to the airport and they never showed up...if you want some pictures of what I have at home I will be happy to send them to you. IN about two weeks! Robert G. Oler WB5MZO Life member Amsat/ARRL Date: Sun, 23 Jan 2011 12:47:10 -0500 From: rjl...@gmail.com To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Observations/Question I've been on the birds off an on for years. I have an M2 cir. polarized pair at home QTH and am looking into a more modest installation for a summer cottage. I've built the K5OE eggbeater imitations and founds them to be only fair.I could by M2 eggbeater pair but I'm trying to do this on less $. I also have an Arrow antenna which I've tried some with a HT with only fair results. Any other suggestions out there? Mount the Arrow more permanently but at a fixed elevation and use a simple rotor to change azimuth? How about a homebrewed quagi? Any suggestions appreciated. Rick W2JAZ ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna rotator test
Hello Nayer, I have not seen any other's response, so, here is mine Performance verification, one step at a time. I verify performance and calibrate all scales before the positioners are put on the tower. Start off reading the instruction manual for operation and maintenance. Replace any corroding hardware as needed, one piece at a time. Be sure all hardware is torqued properly and NOT loose. Do not hesitate to grease all threads with a tenacious axle grease, all aseembly bolts/screws and clamps. The grease allows you to take stuff apart 10 years later. Before connecting anything, measure the resistance of the AZ and EL positioner internal position indicating potentiometer. Do the numbers agree with the manual ? Measure the motor winding resistances. Do both the AZ and the EL positioners. Document findings. Is the manual in agreement ? Determine how much rotator control cable length you will need Sketch out a wiring diagram and document the wire color scheme you will be using. (My 8 conductor rotator control cable uses 8 different colors.) Assemble the cable to the AZ and EL rotator with the actual length of rotator control cables to be used. Do not add antennas at this time. Orient the AZ and EL positioners as they would be used. Measure the resistance of the AZ and EL motor windings, with the cable attached, at the controller end of the cable. Measure the resistance of the indicator potentiometer for both AZ and EL. Document your findings. Are readings reasonable ? Correct any problem. Wire up the control cables to the controller and add a means of measuring the AC current to the controller. Apply AC power to the controller and note the AC current draw. Exercise the AZ rotator, verify that the AZ rotator turns clockwise or counterclockwise as activated. Note the AC current when the AZ rotator is turning. AC current should be the same CW or CCW rotation. Is the azimuth indicator going thru it's entire display range ? Calibrate the AZ display according to the manual. Verify position range after any adjustments. Some AZ controllers only go 360 degrees +/- a few degrees , some go more. Park the AZ positioner at one end of its rotation. I call this NORTH. (0.0 degrees true north) Exercise the EL posioner, Calibrate the display as indicated in the manual. Not the mechanical noise to the AZ or EL motor turning. Measure AC current to the positioner as the EL motor is turning max speed. Document. Park the EL positoner at 0.0 degrees elevation. Measure the AC or DC current from the controller to the AZ and EL positioner, document. Measure the voltage at the controller output, no load and full speed positioner load Disassemble and reassemble on the tower. Add the antennas Slip the mast for 0 degrees true north. Torque down the mast clamps Slip the boom for 0 degrees elevation. Torque down the boom clamps. Exercise the AZ and EL over its full range. Measure AC current to the controller with antenna loading. Measure the AC or DC current from the controller to the positioner, with antenna loading. Document findings. Play satellite. I hope this helps Stan, w1LE Cape Cod FN41sr On 11/8/2010 7:37 AM, N. Mahdinejad wrote: Dear all. Thanks for Bob W7LRD and Greg D for answering to my last question. Is there any standard document or other for test antenna rotator? Some functional and environmental tests. If anyone is familiar with these tests, please send me a link to read or download some useful documents. Any help would be gratefully appreciated. Best regards. Nayer Mahdinejad. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Greg, I would keep the one that works the best. I have been disappointed in the performance of long boom Yagi's for UHF. Resistance loss in the elements often reduces the gain by several dB over calculated gain. Also they are very narrow band, the helix is good for an octave. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Greg D. Sent: Tuesday, September 21, 2010 10:04 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Opinions? Hi folks, So, we had a swap meet a couple of weekends ago, and I found a bargain I couldn't refuse. Of course, now I need to decide what to do with it... The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. The problem is that I already have a 1296mHz antenna. Home-made, circularly polarized, 18 turns Helix. Should be something like 17dBic, if the calculations are correct. In the shack, which is at the wrong end of 60' of 1/2 hardline and a total of about 15' of RG-213 or something like it, I have my Yaesu 736R and its 10 watts of screaming RF power. No preamps. Which antenna should I keep up on the rotor assembly? Last weekend I put up the new antenna. I've made one AO-51 LU pass with the new antenna, and I was not impressed. Several times I couldn't get into the bird, presumably because of the crossed polarization. But when I did get in, it was full quieting, even at low elevations. I don't recall having this much trouble with the Helix. I think AO-51 is the only current satellite on L-band, right? For other uses, there's nothing terrestrial to aim at, repeaters-wise; they're all hiding behind one or more hills, or went off the air years ago. That leaves Weak Signal work (hence the horizontal mounting). I do have one shot into the valley, to the North West, but probably slim pickings for contacts. I haven't tried EME. I'm leaning towards putting the Helix back up, and passing the new one on to someone more able to use it. What are your thoughts? Thanks, Greg KO6TH ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb __ Information from ESET NOD32 Antivirus, version of virus signature database 5468 (20100921) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 5468 (20100921) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Hi Greg et al I have been partial with the helix for satellites. I run 10W to a 16 turn helix through 40 feet of LMR-400. I rarely have an issue getting into AO-51. I believe AO -51 is our only L band bird, I try to exercise my gear when the opportunity is there. I experience very little fading with the L band uplink, input to the satellite is quite solid down to fairly low elevations. The yagi would as you mentioned would better for terrestial 1.2ghz stuff. 73 Bob W7LRD - Original Message - From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Sent: Tuesday, September 21, 2010 10:03:31 PM Subject: [amsat-bb] Antenna Opinions? Hi folks, So, we had a swap meet a couple of weekends ago, and I found a bargain I couldn't refuse. Of course, now I need to decide what to do with it... The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. The problem is that I already have a 1296mHz antenna. Home-made, circularly polarized, 18 turns Helix. Should be something like 17dBic, if the calculations are correct. In the shack, which is at the wrong end of 60' of 1/2 hardline and a total of about 15' of RG-213 or something like it, I have my Yaesu 736R and its 10 watts of screaming RF power. No preamps. Which antenna should I keep up on the rotor assembly? Last weekend I put up the new antenna. I've made one AO-51 LU pass with the new antenna, and I was not impressed. Several times I couldn't get into the bird, presumably because of the crossed polarization. But when I did get in, it was full quieting, even at low elevations. I don't recall having this much trouble with the Helix. I think AO-51 is the only current satellite on L-band, right? For other uses, there's nothing terrestrial to aim at, repeaters-wise; they're all hiding behind one or more hills, or went off the air years ago. That leaves Weak Signal work (hence the horizontal mounting). I do have one shot into the valley, to the North West, but probably slim pickings for contacts. I haven't tried EME. I'm leaning towards putting the Helix back up, and passing the new one on to someone more able to use it. What are your thoughts? Thanks, Greg KO6TH ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
M2 makes a 35 element 1296 MHz yagi, on about a 6' boom. individual elements are insulated thru the boom with keepers. Folded dipole driven element. I used 2 each stacked vertically for AO-40. Yes, they are pointy. Stan, W1LE Cape Cod FN41sr On 9/22/2010 1:52 AM, Art McBride wrote: Greg, I would keep the one that works the best. I have been disappointed in the performance of long boom Yagi's for UHF. Resistance loss in the elements often reduces the gain by several dB over calculated gain. Also they are very narrow band, the helix is good for an octave. Art, KC6UQH -- ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
- Original Message - From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Sent: Wednesday, September 22, 2010 7:03 AM Subject: [amsat-bb] Antenna Opinions? Hi folks, The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. Thanks, Greg KO6TH Hi Greg, KO6TH It is probably a Tonna 35 element yagi. 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
I installed one of these a few months ago, in place of my 20-turn Wimo helix. Both are nice antennas, but I'll give the edge to the M2 yagi (more gain and it mounts balanced on the elevation boom). I have mine with vertical polarity. Since AO-51 is linear on L-band, it shouldn't matter--but putting that little antenna horizontal in line with my metal boom didn't seem to make much sense 73, Mark N8MH On Wed, Sep 22, 2010 at 8:50 AM, Stan, W1LE stanw...@verizon.net wrote: M2 makes a 35 element 1296 MHz yagi, on about a 6' boom. individual elements are insulated thru the boom with keepers. Folded dipole driven element. I used 2 each stacked vertically for AO-40. Yes, they are pointy. Stan, W1LE Cape Cod FN41sr On 9/22/2010 1:52 AM, Art McBride wrote: Greg, I would keep the one that works the best. I have been disappointed in the performance of long boom Yagi's for UHF. Resistance loss in the elements often reduces the gain by several dB over calculated gain. Also they are very narrow band, the helix is good for an octave. Art, KC6UQH -- ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Mark L. Hammond [N8MH] ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
- Original Message - From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Sent: Wednesday, September 22, 2010 7:03 AM Subject: [amsat-bb] Antenna Opinions? Hi folks, The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. Thanks, Greg KO6TH Hi Greg, KO6TH If your antenna is from Tonna it must be 3,07 meters long. Tonna make two models one for DX and SAT and the other one for ATV By the way the gain is 20 dB isotropic. 20635 35 ELEMENTI 1260/1300 MHz dx,sat 20 dB 3,07 meters long 20636 35 ELEMENTI 1250/1260 MHz ATV 20 dB 3,07 meters long 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Okay, my 35 ele M2 is about 10 feet long: http://www.m2inc.com/index2.html They do sell a 22 element version that is about 6' long: http://www.m2inc.com/index2.html Mark N8MH On Wed, Sep 22, 2010 at 9:10 AM, Mark L. Hammond marklhamm...@gmail.com wrote: I installed one of these a few months ago, in place of my 20-turn Wimo helix. Both are nice antennas, but I'll give the edge to the M2 yagi (more gain and it mounts balanced on the elevation boom). I have mine with vertical polarity. Since AO-51 is linear on L-band, it shouldn't matter--but putting that little antenna horizontal in line with my metal boom didn't seem to make much sense 73, Mark N8MH On Wed, Sep 22, 2010 at 8:50 AM, Stan, W1LE stanw...@verizon.net wrote: M2 makes a 35 element 1296 MHz yagi, on about a 6' boom. individual elements are insulated thru the boom with keepers. Folded dipole driven element. I used 2 each stacked vertically for AO-40. Yes, they are pointy. Stan, W1LE Cape Cod FN41sr On 9/22/2010 1:52 AM, Art McBride wrote: Greg, I would keep the one that works the best. I have been disappointed in the performance of long boom Yagi's for UHF. Resistance loss in the elements often reduces the gain by several dB over calculated gain. Also they are very narrow band, the helix is good for an octave. Art, KC6UQH -- ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- Mark L. Hammond [N8MH] -- Mark L. Hammond [N8MH] ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
I use a Directive Systems 25 element loop yagi and it works great for AO-51 L band. http://www.directivesystems.com I'm feeding it with 10 watts via 35 feet of LMR400. Directive Systems antennas are very well built and less expensive than some other popular brands. Steve N5EN --- ko6th_g...@hotmail.com wrote: From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna Opinions? Date: Tue, 21 Sep 2010 22:03:31 -0700 Hi folks, So, we had a swap meet a couple of weekends ago, and I found a bargain I couldn't refuse. Of course, now I need to decide what to do with it... The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. The problem is that I already have a 1296mHz antenna. Home-made, circularly polarized, 18 turns Helix. Should be something like 17dBic, if the calculations are correct. In the shack, which is at the wrong end of 60' of 1/2 hardline and a total of about 15' of RG-213 or something like it, I have my Yaesu 736R and its 10 watts of screaming RF power. No preamps. Which antenna should I keep up on the rotor assembly? Last weekend I put up the new antenna. I've made one AO-51 LU pass with the new antenna, and I was not impressed. Several times I couldn't get into the bird, presumably because of the crossed polarization. But when I did get in, it was full quieting, even at low elevations. I don't recall having this much trouble with the Helix. I think AO-51 is the only current satellite on L-band, right? For other uses, there's nothing terrestrial to aim at, repeaters-wise; they're all hiding behind one or more hills, or went off the air years ago. That leaves Weak Signal work (hence the horizontal mounting). I do have one shot into the valley, to the North West, but probably slim pickings for contacts. I haven't tried EME. I'm leaning towards putting the Helix back up, and passing the new one on to someone more able to use it. What are your thoughts? Thanks, Greg KO6TH ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Greg, My two cents is that AO-51 seems to be very sensitive on the L band receive, so a decent antenna will get in fine. I have been using RHCP on my uplink, a 31 turn homebrew helix modeled after the VE3NPC, and I have not experienced any fading problems on uplink. My choice then is to opt for the circular polarization. I do feed mine directly at the antenna (about 5 feet of LMR-400 from the upconverter) but I think your helix with the power you are feeding it is probably quite capable and a better idea to avoid the fading. 73, Jerry N0JY Hi folks, So, we had a swap meet a couple of weekends ago, and I found a bargain I couldn't refuse. Of course, now I need to decide what to do with it... I'm leaning towards putting the Helix back up, and passing the new one on to someone more able to use it. What are your thoughts? Thanks, Greg KO6TH ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Hi Stan, No, it's for sure not an M2. The boom is about 9' or 10' long, and the driven element is a simple dipole. The reflector element in the back is split, with two dipoles, one above and one below the boom. Coax connector is at the rear of the boom. The pointiness of the antenna is not too bad. My rotor is good to 6 degrees (that's the clicker increment), and the one beacon I can barely hear way off in the distance can be heard +/- about 2 clicks. Greg KO6TH Date: Wed, 22 Sep 2010 08:50:05 -0400 From: stanw...@verizon.net To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Antenna Opinions? M2 makes a 35 element 1296 MHz yagi, on about a 6' boom. individual elements are insulated thru the boom with keepers. Folded dipole driven element. I used 2 each stacked vertically for AO-40. Yes, they are pointy. Stan, W1LE Cape Cod FN41sr On 9/22/2010 1:52 AM, Art McBride wrote: Greg, I would keep the one that works the best. I have been disappointed in the performance of long boom Yagi's for UHF. Resistance loss in the elements often reduces the gain by several dB over calculated gain. Also they are very narrow band, the helix is good for an octave. Art, KC6UQH -- ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Opinions?
Hi Domenico, The length sounds about right (I didn't measure it, but it's longer than my garage 8 foot ceiling is high). But searching for pictures of the Tonna antenna, I'm not seeing one that matches. The Tonna antennas have a different mounting (a parallel bar below the boom), and elements above the boom, or so it seems. I have put some pictures of the mounting for this antenna, and the overall array: http://home.wavecable.com/~ko6th/dsc00319-800.jpg shows the mounting, and element style. There is another similar block of metal at the rear of the antenna; slightly smaller, but with the same type of pipe fittings going up and down. The PVC pipe mounting is mine. 1/2 pipe elbow, slathered with glue and tapped into place with a hammer. Seems to work. and http://home.wavecable.com/~ko6th/dsc00320-1024.jpg for the whole thing. You can barely see the back of the antenna in this image, with the split reflector. The coax cable is hooked to a 90-degree elbow, so that it hangs down without kinking (and so it can reach!). Left to right are a 2x15 element 70cm antenna (also unknown pedigree), 13cm BBQ dish, 23cm antenna, tower camera in box, and 8 element 2m antenna. The cross boom is a wooden closet pole, and yes, the weight of the dish is causing a bit of a sag... Hence my earlier thread about replacing it with a pair of flat panel Wi-Fi antennas. I haven't finished that project yet. If the gain is more like 20dBi (the seller claims 23), then the difference between my 18 turn helix and the 35 element yagi is even less. For satellite use, the helix probably wins because of the circular polarization. In terrestrial work, I lose 3db going circular to linear, so the net difference is going to be about 6dB. Not trivial, but not wow either. The helix is a lot smaller of an antenna, too, thinking of wind load and such. Greg KO6TH From: domenico.i8...@tin.it To: ko6th_g...@hotmail.com; amsat-bb@amsat.org Subject: Re: [amsat-bb] Antenna Opinions? Date: Wed, 22 Sep 2010 15:17:15 +0200 - Original Message - From: Greg D. ko6th_g...@hotmail.com To: amsat-bb@amsat.org Sent: Wednesday, September 22, 2010 7:03 AM Subject: [amsat-bb] Antenna Opinions? Hi folks, The Find was a 35 element 1296mHz antenna, well built and in excellent condition. Linearly polarized, horizontal; supposed to be 23dBi gain. Manufacturer, of course, is unknown. No markings, but it does not look home-built. By the mounting hardware, it looks like it was part of some sort of stacked array. Thanks, Greg KO6TH Hi Greg, KO6TH If your antenna is from Tonna it must be 3,07 meters long. Tonna make two models one for DX and SAT and the other one for ATV By the way the gain is 20 dB isotropic. 20635 35 ELEMENTI 1260/1300 MHz dx,sat 20 dB 3,07 meters long 20636 35 ELEMENTI 1250/1260 MHz ATV 20 dB 3,07 meters long 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna question continued
Jacob, for what it is worth, I built the 'eggbeater' and it was so 'noisy' tossed it. Built the dual Moxon out of brass tubing from the hobby shop and just love it !!! (I'm a big Moxon fan as you can tell) The Moxi works for me. But, since you already have the KLM's, not sure you will do better for LEO omni than that. 73, Ted -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Jacob Tennant Sent: Saturday, May 01, 2010 6:27 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Antenna question continued OK so to continue my antenna question further, I have seen plans for the K5OE Eggbeater antenns, dual moxons for LEO's, as well as the EZ-Lindenblad antennas for small satellite antennas. Of these what is the general consensus as to the better of them? I am looking for something small and easy to setup for Field Day, portable operation where a dual beams and rotator setup would be cumbersome to use. I already have plans for the beams I have to be setup here at the house. Thank you everyone for indulging my curiousity... Jacob Tennant - K8JWT ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna question continued
In a message dated 5/2/2010 6:46:20 P.M. Eastern Daylight Time, k7trkra...@charter.net writes: I already have plans for the beams I have to be setup here at the house I wish you the best of luck Jacob with your setup. I did quite a bit of outdoor operation with a handheld sat antenna which was fun (3 VHF elements 7 UHF elements). Nice to be able to adjust elevation, azimuth, and polarization with just a twist of the wrist for best reception. Looking forward to hearing you on the birds. - - - I'm located near Charleston. Glad to see another West Virginian here on the list. 73, Gary -K8KFJ- Sat VUCC #125 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna
Date: Mon, 29 Mar 2010 02:27:02 -0400 From: Larry Lucas lawrencelu...@verizon.net Subject: [amsat-bb] Antenna To: amsat-bb@amsat.org Message-ID: c63a57d1c94647ffa4f284aa62981...@dadslap Content-Type: text/plain; charset=us-ascii I am new at this and would like to find the plans to build a simple homebrew antenna to be able to use satellites. I know there are probably several so can you direct me to some of the simple and easiest and best? THANKS The IOio seems to be a popular one. I built one and blogged about it, with some tips and photos, here: http://kj6akq.nerdnetworks.org/2010/02/building-an-ioio-satellite-antenna.html I intend to build one of these micro-diplexers to use with it, but haven't yet: http://k0lee.com/duplexer.htm Good luck! -- Owen B. Mehegan (o...@nerdnetworks.org) ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna setup
About 15 degrees elevation is usually considered optimum. ...and the booms angled 30 to 40 degrees... up Yes, NEVER higher than 15 degrees. You don't need the gain much above the horizon where the satellite is up to 10 dB CLOSER. You DO need the gain on the horizon where the satellite is 10 dB further away. See the plot on www.aprs.org/rotator1.html Pay particular attention to the scale drawing of a LEO orbit to the ground station. Tracking a LEO satellite is like sitting 100 yards from an infinitely long east-west railroad track and using your beam to communicate with a train. 1) You point your antenna almost due west (-15 degrees or so) so that the infinite distance is still in the main beam PLUS all the track almost up to where you are. Then the approaching train is ALWAYS in your main beam until it is 100 yards away (where it is now 45 degrees from your location). But then it is so strong, you can hear it on a wet noodle. 2) For those three seconds as it goes by, it is not in your main beam, but it is so strong who cares. 3) Swing the beam now due east (minus about 15 degres) and again, for the entire rest of the pass, the train is in your main beam. If you put your beam in either case 30 or 40 degrees away from the track, you would miss the MAJORITY of the time the train is traveling, because the MAJORITY of the time, it is far far away and not in your main beam. We must dispell any literature that even hints that an angle above 15 degrees is good for LEO satellites (of course there are always exceptions)... For example, you live in a HOLE! Then it makes no sense to set your antenna at 15 degrees if that is still pinting into surrounding dirt. Common sense then applies. Bob, WB4APR ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna setup
Yes, NEVER higher than 15 degrees. You don't need the gain much above the horizon where the satellite is up to 10 dB CLOSER. Bob, Looks like you Navy guys have been using this technique since the early 1960's. Check out the photo Radio Control Hut Team Overseas on http://www.globalsecurity.org/space/systems/grab.htm -Joe KM1P ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna setup
About 15 degrees elevation is usually considered optimum. On 12-Mar-10 01:32, Jacob Tennant wrote: and the booms angled 30 to 40 degrees front end up -- Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032 Amateur Radio G8IFF W8IFF (was KC8NHF), e-mail ni...@ngunn.net www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pigs QRP Club International #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK 0182, MKARS, ALC, GCARES, XWARN. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna setup
Hi Jacob, My satelite antenna is 4 elements on 2 meters and 8 elements on 430 with a pre-amp mounted on the UHF boom. The UHF antenna is used for receive only. Take a look at it on QRZ.com under my call sign. WA7HQD Lee Ernstrom Syracuse, Utah DN31xb -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Jacob Tennant Sent: Thursday, March 11, 2010 6:32 PM To: Amsat BB Subject: [amsat-bb] Antenna setup Hello everyone, I have a antenna setup question as I am new to satellite operations so please bear with me... I have a 2meter beam and a 70cm beam from my former adventures into VHF weak signal operations and was wondering about using them for satellite work. Was thinking that since I don't have a az/el rotator yet, if I set them up on a single cross-boom with the TV rotator I have now, angle them with the elements at 45 degree angles and the booms angled 30 to 40 degrees front end up I might be able to get some decent ability into the FM satellites (AO51, SO50, AO27, ISS). I already have the good coax for them (LMR-400) and a duplexor for my FT-857D. Was going to try to install the antennas on top of my storage building with a height of approx. 16 feet. That's the highest structure I can get onto that belongs to me. Any alternate ideas or advice is always welcome as I said before this is all new to me. Jacob Tennant - K8JWT Morgantown,WV FM09ap ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna setup
out here in 6 land I keep my 5 el on 2 mtr and 11 elements on 70cm (both horizontal) at 30 degs above my HF beam and miss very little on FM or SSB birds N6RSX -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org]on Behalf Of Nigel Gunn G8IFF/W8IFF Sent: Thursday, March 11, 2010 6:26 PM To: k8...@comcast.net Cc: Amsat BB Subject: [amsat-bb] Re: Antenna setup About 15 degrees elevation is usually considered optimum. On 12-Mar-10 01:32, Jacob Tennant wrote: and the booms angled 30 to 40 degrees front end up -- Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032 Amateur Radio G8IFF W8IFF (was KC8NHF), e-mail ni...@ngunn.net www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pigs QRP Club International #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK 0182, MKARS, ALC, GCARES, XWARN. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb NOTICE: This communication may contain privileged or other confidential information. If you are not the intended recipient of this communication, or an employee or agent responsible for delivering this communication to the intended recipient, please advise the sender by reply email and immediately delete the message and any attachments without copying or disclosing the contents. Thank you. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna question
Some maritime TVRO antennas used a mechanical scan at the feed point. A motor would either rotate an attenuator disk or offset the feed in a circular motion. A resolver kept track of the feed location in relation to received signal strength. The antenna was then slewed in the direction of best signal in both AZ and EL. Sort of a poor mans monopulse system. This works OK for antennas in the microwave region but would not work to well for VHF/UHF low gain arrays. What might work well is to use a pair of antennas with a doppler scan circuit that steered the rotor toward the estimated direction of the signal. Howie AB2S _ Windows 7: Simplify your PC. Learn more. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen1:102009 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna question
While searching for public text concerning Amateur satellites and phased array antennas, I came across this gem from our very own Tom Clark, K3IO http://mysite.verizon.net/w3iwi/electronic_scanning_antennas.pdf, Electronic Scanning Antennas for Amateur Spacecraft. I wonder if this knowhow could be utilized for ground stations to have antennas that could rapidly switch between different birds by a software reload function and a intelligent switching matrix ? How many of you would prefer (if a command station) to have multi-access to satellites as they pass during conjunction but use a small antenna farm selectively to access them _simultaneously_. On Thu, Oct 22, 2009 at 3:06 PM, Samudra Haque samudra.ha...@gmail.com wrote: Hi, Amsat-BB Are there any antenna designs that use predominantly rotating sub-reflectors and a reflector for tracking LEO birds, in contrast to rotating the main antenna structure on booms in the AZ-EL directions ? I am aware of multi-LNB antenna arrangements, thought it would be interesting to find out ways to keep a fairly large reflector constant on the ground and use a smaller steerable sub-reflector or horn feed to aim the beam ? Any ideas ? Samudra N3RDX ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna question
This is a great paper and solid work. It doesnt have a chance of being implemented on an amateur radio budget or time scale to the point where a solid reliable platform can be flown. What the satellite group needs is more Oscar 7's (or VO 52's) and Oscar 10...Arsene and Oscar IV were not bad concepts. Face it, we are not going to make working the world on an HT a viable proposition. Robert WB5MZO From: samudra.ha...@gmail.com Date: Thu, 22 Oct 2009 15:16:25 -0400 To: amsat-bb@amsat.org Subject: [amsat-bb] Re: antenna question While searching for public text concerning Amateur satellites and phased array antennas, I came across this gem from our very own Tom Clark, K3IO http://mysite.verizon.net/w3iwi/electronic_scanning_antennas.pdf, Electronic Scanning Antennas for Amateur Spacecraft. I wonder if this knowhow could be utilized for ground stations to have antennas that could rapidly switch between different birds by a software reload function and a intelligent switching matrix ? _ Windows 7: It helps you do more. Explore Windows 7. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen3:102009 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: antenna question
Samudra, You could use a polar mount and preset mast angle and azmuth before each pass. That will give you a single axis control. Most antennas are moer that 30 degrees in beamwidth, the system only needs to be close +/- 15 degrees to have max signal. Art, KC6UQH -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Samudra Haque Sent: Thursday, October 22, 2009 12:16 PM To: Amsat-bb Subject: [amsat-bb] Re: antenna question While searching for public text concerning Amateur satellites and phased array antennas, I came across this gem from our very own Tom Clark, K3IO http://mysite.verizon.net/w3iwi/electronic_scanning_antennas.pdf, Electronic Scanning Antennas for Amateur Spacecraft. I wonder if this knowhow could be utilized for ground stations to have antennas that could rapidly switch between different birds by a software reload function and a intelligent switching matrix ? How many of you would prefer (if a command station) to have multi-access to satellites as they pass during conjunction but use a small antenna farm selectively to access them _simultaneously_. On Thu, Oct 22, 2009 at 3:06 PM, Samudra Haque samudra.ha...@gmail.com wrote: Hi, Amsat-BB Are there any antenna designs that use predominantly rotating sub-reflectors and a reflector for tracking LEO birds, in contrast to rotating the main antenna structure on booms in the AZ-EL directions ? I am aware of multi-LNB antenna arrangements, thought it would be interesting to find out ways to keep a fairly large reflector constant on the ground and use a smaller steerable sub-reflector or horn feed to aim the beam ? Any ideas ? Samudra N3RDX ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb __ Information from ESET NOD32 Antivirus, version of virus signature database 4535 (20091023) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 4535 (20091023) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna Polarization
- Original Message - From: Patrick Domack patric...@patrickdk.com To: amsat-bb@amsat.org Sent: Wednesday, September 23, 2009 4:11 AM Subject: [amsat-bb] Antenna Polarization I've been meaning to setup some antennas for satellite operation for awhile here. And since I will probably end up doing it this fall/winder I had a question I was wondering about, before I get the antennas completely built connected up. I plan on using a circular polarized antenna, for lhcr and rhcr. Since this setup has two coax that your switch a 1/4wave (if I remember right) to either side to create the two rotations in the antenna. Is there a way I can modify this to feed two radios? so one radio would receive lhcr, and the other rhcr? Or would I be forced to use two antennas to do this? The only idea I have is to use a signal splitter on each of the two antenna halfs before joining them, then join each of those splits into the cr parts. But I'm not sure if there is a better way to do this without as much loss, or if this might cause a backfeed that would defeat the me from getting any signal at all. Maybe there is a good writeup of this on the web somewhere, but I have no clue what the proper terms to google it are, and haven't had any luck. Thanks. Hi Patrick What you propose to do is possible in theory but you need four 3 dB power dividers with characteristic impedance of 36 ohm each and 14 N/m male connectors so that the total losses of the system are too high. I suggest to switch from RHCP to LHCP over the same receiver using only a coax relay as described in all antenna books of the ARRL or into The Satellite Experimenter's Handbook by Martin Davidoff K2UBC edited by the ARRL 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna pointing
I use a plumb bob and plumb line. When north star is first visible, I use these to determine true north on my horizon. I then create in my mind a picture of where that point is on the horizon. Then during daytime, I adjust antenna to point at that point on the horizon. A south-north road near my QTH is aligned with the same horizon point. Larry W7IN ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna pointing
John and all, I mean no disrespect, and I'll apologize now if what follows offends you or anyone. I agree - to a point - about pointing accuracy. Let's face it - of the three FM satellites currently available to us, SO-50 is the largest target we have. It is a 35mm (13.78-inch) cube. We're shooting signals at it from hundreds of miles away, so even the most accurate of pointing likely is a little of dead-center ... hihi. That fact notiwthstanding, however, I remain convinced that each individual station has its own sensitivity to pointing accuracy relative to effective communications. Stations running relatively high power levels and well-calibrated motorized antenna systems likely can be less accurate and still be effective. I don't believe I and others enjoy that luxury when we set out to work the satellites on handheld stations running lower power levels - in some cases, much lower power levels. The International Space Station provides at least a partial illustration. Here, I don't worry about Doppler tuning with the ISS because (1) it's orbit is lower (thus, it's closer) and (2) its radio runs significantly more power than any of our other smateur satellites. Even at a low power setting of 5 watts out, it is 20x more powerful than SO-50 and 10x more powerful than AO-27. I don't have to be as careful with pointing or Doppler tuning to enjoy a good experience on an ISS pass. Not so when trying to capture and keep, for example, AO-27's half-watt signal. Before I started working the amateur satellites about 14 months ago, I had spent several years enjoying visible passes of the ISS whenever I could. As I learned of the available amateur satellites and decided to give them a try with a handheld station, it became apparent to me very quickly that my practice on the ISS would be helpful. I use a compass to match AOS/mid-pass/LOS positions with known landmarks here, and then I visualize how a satellite will arc across the sky relative to my location on a given pass. I believe that has improved my pointing accuracy significantly, and I further believe that accuracy makes a difference at times in whether I make a successful contact. This morning on AO-51, I made contacts with KB1RVT in Maine and WA3SWJ in Maryland. Those contacts provided the 29th and 30th states I have worked on the FM satellites using my Yaesu VX-7R HT set at 50 milliwatts (.05-watt) output. I have used either an Arrow dual-band yagi or my current Elk dual-band log periodic to make all of those flea power contacts. I don't believe any would have been possible without pointing and tracking that is as accurate as I can make it, given my hand-holding and manual tracking. That being said, I believe your creation of an antenna bore sight is an outstandning idea - one that will help anyone improve the effectiveness of stations using tower/mast-mounted antennas with motorized Az/El rotation systems. Congratulations on that, and thank you for sharing it with the BB. 73 to all, Tim - N3TL Athens, Ga. - EM84ha From: john heath g7...@btinternet.com To: amsat amsat-bb@amsat.org Sent: Thursday, August 13, 2009 1:16:33 PM Subject: [amsat-bb] Antenna pointing Hi, I agree with the comments that high degrees of pointing accuracy are not required for satellite work. However, if you are super keen to improve your pointing accuracy then you may like to consider the modern version of the bore sight method. A bore sight is basically a length of tube, you look through, you only get a view of the target when you are accuratly lined up with it. The longer the tube the greater the pointing accuracy. For an antenna boom mounted bore sight I used about six inches of 15mm copper water pipe with a stop end soldered onto it. I drilled a 1/8 hole in the stop end and fixed a light dependant resistor in the eye end Attached to the boom and ran wires to the shack where I had a battery and voltmeter. Point your antenna at where the Sun should be then hunt backwards and forwards, up and down until you see a peak reading on the meter = the sun. Its a bit of work but the benefit of this method is that its on the tower and you can check it anytime the Sun is out. Practical problems, waterproofing and true alignment to the boom. It was a lot of work but a fun project, eventially destroyed by water penetration. 73 John G7HIA ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna pointing
Hi Tim and the list, Thanks for the kind comments. Its not my original idea. I picked it up years ago, possibly from Amsat-UK's journal OSCAR News, or possibly eleswhere. Just happy to pass it on. Someone may find it usefull, or suggest a better/simpler implimentation of the same basic idea. 73 John G7HIA ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna project with 2 ELK antennas
- Original Message - From: Jean-François Ménard jf.va...@gmail.com To: AMSAT Mailing list amsat-bb@amsat.org Sent: Thursday, August 06, 2009 10:44 PM Subject: [amsat-bb] Antenna project with 2 ELK antennas Hi, I have 2 ELK antennas here, and I would like to do an experiment with these two antennas. I would like to stack side by side, one vertical, and one horizontal. 73 Jean-François Ménard VA2SS =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMSAT www.amsat.org / Member #37102 ARRL www.arrl.org =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Hi Jean, VA2SS Staking 2 ELK antennas side by side,one vertical,and one horizontal what type of polarization you plan to get ? 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: Antenna project with 2 ELK antennas
Le 8 août 2009 11:54, i8cvsdomenico.i8...@tin.it a écrit : Hi Jean, VA2SS Since the ELK antenna is a log-periodic antenna covering a wide band from 2 meters and 70 cm it is difficult to connect 2 ELK in phase and gain 3 dB in 2 meters and 70 cm as well. Also it is difficult to connect 2 ELK with a phase offset of 90° to get circular polarization in 2 meters and 70 cm I would prefere to put one ELK horizontal and the other one vertical feeding each antenna with an individual coax line. Using a coax relay in the shack you can immediately switch from the Horizontal to the Vertical polarization. About the distance between the antennas over the plastic boom the distance is a function of the antenna gain and higher is the gain (in order do not overlap the aperture area of each antenna) larger must be the distance between booms Since the gain of the ELK in the lover 2 meters band is 6.6 dBd over the dipole or 6.6 +2.14 = 8.7 dBi over the isotropic then the aperture area wich is a circle perpendicular to the antenna boom can be computed using the following formula: / 2 G x /\ Aperture area= -- 4 x Pi Since G= 8.7 dBi = 7.41 in power ratio 2 7.41 x 2 Aperture area= -- = 2.36 square meters 4 x 3.14 A circle with a geometrical area of 2.36 square meters has a radius of \ / radius = \ / 2.36 / 3.14 = 0.86 meters \/ Hence the distance between the booms is 0.86 x2 = 1.72 meters In this condition both aperture areas are tangents but it is better to overlap the areas a 10 % to prevent the generation of side lobes so that a distance of 1.55 meters between the antenna booms is recommended. I hope this helps 73 de i8CVS Domenico - Original Message - From: Jean-François Ménard jf.va...@gmail.com To: i8cvs domenico.i8...@tin.it Sent: Saturday, August 08, 2009 4:00 PM Subject: Re: [amsat-bb] Antenna project with 2 ELK antennas Hi, I do not know much about antenna... But I tought that could be better for satellite this way... I did not do any search at this time about this project... it is only an idea that I had. If you have any suggestion for such project using 2 Elk antenna please let me know. I don't want to spend much money at this moment... and I have only these 2 antenna. Wow !! Thanks !! This is the kind of answer that I really like. I will try this with the recommendation you gave me. I'm not familiar with all those formulas regarding antenna, so a little help time to time is really helpful I like to learn, so you won't repeat the same thing twice. Thank again. Best 73 J-F VA2SS 73 2009/8/8 i8cvs domenico.i8...@tin.it: - Original Message - From: Jean-François Ménard jf.va...@gmail.com To: AMSAT Mailing list amsat-bb@amsat.org Sent: Thursday, August 06, 2009 10:44 PM Subject: [amsat-bb] Antenna project with 2 ELK antennas Hi, I have 2 ELK antennas here, and I would like to do an experiment with these two antennas. I would like to stack side by side, one vertical, and one horizontal. 73 Jean-François Ménard VA2SS =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMSAT www.amsat.org / Member #37102 ARRL www.arrl.org =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Hi Jean, VA2SS Staking 2 ELK antennas side by side,one vertical,and one horizontal what type of polarization you plan to get ? 73 de i8CVS Domenico -- Jean-François Ménard VA2SS =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMSAT www.amsat.org / Member #37102 ARRL www.arrl.org =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= -- Jean-François Ménard VA2SS =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= AMSAT www.amsat.org / Member #37102 ARRL www.arrl.org =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
