[amsat-bb] Giant Fly Almost Interrupts Falcon 9
It was close - but the giant fly seen at T MINUS FIVE SECONDS did not interrupt today's spectacular space mission. http://bit.ly/dx9Vot Clint, K6LCS ___ 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] F9 launch
http://www.youtube.com/watch?v=sP5gykvTBpM -- (Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. “Be yourself, because the people who mind don't matter. And the people that matter don't mind. -Dr. Seuss Active: Facebook,Twitter,LinkedIn ___ 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: Giant Fly Almost Interrupts Falcon 9
Nah, that was a Texas Mosquito --- On Sat, 6/5/10, Clint Bradford clintbradf...@mac.com wrote: From: Clint Bradford clintbradf...@mac.com Subject: [amsat-bb] Giant Fly Almost Interrupts Falcon 9 To: amsat-bb@amsat.org Date: Saturday, June 5, 2010, 12:57 AM It was close - but the giant fly seen at T MINUS FIVE SECONDS did not interrupt today's spectacular space mission. http://bit.ly/dx9Vot Clint, K6LCS ___ 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] Next HV Satcom Net
*Hi all, The next HV Satcom net is Thursday June 10 on the 146.97 Mt. Beacon ARC Repeater, there WILL be Ceholink available, the node is:N2EYH-L The time for the net is 8PM (EDT) (or 2400 UTC) More info:www.hvsatcom.org( for the Mt.Beacon ARC home Page): www.wr2abb.org73,.Stu (WABSS;Director) * ___ 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: F9 launch
I was amazed as to how hot the nozzle was. Joe WB9SBD The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 6/4/2010 3:23 PM, Bob McGwier wrote: http://www.youtube.com/watch?v=sP5gykvTBpM ___ 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] FIELD DAY SCORING
Hello, I was in contact with the ARRL, after I read 7.3.7. and 7.3.7.1. in the Field Day Rules. I mentioned to the League that I would like them to point out where in those rules it would prohibit scoring the same call on multiple Linear Satellites. They listened to my point's and agreed that even though the rules refer to satellite contacts as a separate band there is nothing in those rules that prohibit the aforementioned scoring. In conclusion Field Day and the AMSAT scoring are now in agreement, have fun. 73's Pete WB2OQQ www.massapequanyweather.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: FIELD DAY SCORING
That should make it much easier for everyone as you don't have to do one log and then strip out the unwanted calls for the other. Thanks Pete. I am glad that the two minds (ARRL and AMSAT) have become one. 73...bruce From: Peter Portanova r...@optonline.net To: amsaT-BB@amsat.org Sent: Sat, June 5, 2010 9:33:07 AM Subject: [amsat-bb] FIELD DAY SCORING Hello, I was in contact with the ARRL, after I read 7.3.7. and 7.3.7.1. in the Field Day Rules. I mentioned to the League that I would like them to point out where in those rules it would prohibit scoring the same call on multiple Linear Satellites. They listened to my point's and agreed that even though the rules refer to satellite contacts as a separate band there is nothing in those rules that prohibit the aforementioned scoring. In conclusion Field Day and the AMSAT scoring are now in agreement, have fun. 73's Pete WB2OQQ www.massapequanyweather.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 ___ 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: Giant Fly Almost Interrupts Falcon 9
... Nah, that was a Texas Mosquito ... Yet ANOTHER reason to stay in California ... (grin) Clint, K6LCS http://clintbradford.weblog.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: Giant Fly Almost Interrupts Falcon 9
:-) On Sat, Jun 5, 2010 at 10:02 AM, Clint Bradford clintbradf...@mac.com wrote: ... Nah, that was a Texas Mosquito ... Yet ANOTHER reason to stay in California ... (grin) Clint, K6LCS http://clintbradford.weblog.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 ___ 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] AO-27 schedule updated
A new schedule was uploaded to the satellite on May 30th. All users of the Java schedule lister should update your data files to be sure you have the latest schedule. George, KA3HSW ___ 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] WD9EWK - midday Saturday
Hi! This has been a good hamfest here in Show Low AZ. The morning started with 12 QSOs on AO7 around 1400 UTC! More on VO52 and SO50 later. Thanks to K8YSE and KD8CAO in Michigan for the QSOs, as well as N5AFV operating as KK5W in Texas. I will be on SO50 @ 1913 UTC followed by AO27 @ 1937 UTC to wrap up the hamfest demos. Thanks to WA8SME, N5AFV as KK5W, and AA5CK for talking with a Boy Scout that stopped by during the 1730 UTC SO50 pass! Several Scouts were able to satisfy several requirements toward th Radio Merit Badge, including the Scout who was on the mic. My first pass from DM54 (or possibly the DM44/DM54 boundary) will be a shallow AO7 pass at 2256 UTC. Hope to put more in the log then, to go with 33 QSOs wlready logged at the hamfest with two passes remaining. 73! Patrick WD9EWK/VA7EWK - Show Low, Arizona http://www.wd9ewk.net/ ___ 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: Re HELIX REFLECTOR?
john, whats a good rule for height of the antennas to avoid large back lobes reflecting, ie how many wavelengths up should the antennas be? Thanks... --STeve Andre' wb8wsf en82 On Saturday 05 June 2010 17:07:15 John Belstner wrote: Just another $0.02 to add. You will find that the size and shape of the reflector will not affect the forward gain as much as it does the F/B ratio. It depends on what is important to you and (of course) how high you are above the ground. Even for satellite operation pointing up, large back lobes reflecting off the ground can adversely affect the forward pattern when the antenna is mounted only 6-8 feet above ground. On Jun 4, 2010, at 10:13 PM, Clare Fowler wrote: To add to the discussion the July/Aug 2007 Amsat Journal has an article covering some gain comparisonmeasurements I made between four 13 turn (2.88 wavelengths) 13cm antennas with different square solid aluminum reflectors. The sizes were 0.56 wavelengths, 0.84 wavelengths, 1.0 wavelength and 1.4 wavelengths. There was no difference between the 0.84, 1.0 and 1.4 wavelengths but the antenna with the0.56 wavelength reflector had 1.5 db less gain. However for my 70cm helix antennas I followed the Satellite Handbook minimum size of 0.6 wavelengthsor slightly over 16 inches. I used 1/2 inch hardware cloth mesh to keep the weight and windloading down. These antennas have performed well however it appears that they would be a bit better with a somewhat larger reflector. A brief description and picture of the 70 cm reflector is in the November/December 2005 Amsat Journal article on The Development of a Quarter Wave Match for helical antennas. Clare VE3NPC Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU ___ 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: Re HELIX REFLECTOR?
Just another $0.02 to add. You will find that the size and shape of the reflector will not affect the forward gain as much as it does the F/B ratio. It depends on what is important to you and (of course) how high you are above the ground. Even for satellite operation pointing up, large back lobes reflecting off the ground can adversely affect the forward pattern when the antenna is mounted only 6-8 feet above ground. On Jun 4, 2010, at 10:13 PM, Clare Fowler wrote: To add to the discussion the July/Aug 2007 Amsat Journal has an article covering some gain comparisonmeasurements I made between four 13 turn (2.88 wavelengths) 13cm antennas with different square solid aluminum reflectors. The sizes were 0.56 wavelengths, 0.84 wavelengths, 1.0 wavelength and 1.4 wavelengths. There was no difference between the 0.84, 1.0 and 1.4 wavelengths but the antenna with the0.56 wavelength reflector had 1.5 db less gain. However for my 70cm helix antennas I followed the Satellite Handbook minimum size of 0.6 wavelengthsor slightly over 16 inches. I used 1/2 inch hardware cloth mesh to keep the weight and windloading down. These antennas have performed well however it appears that they would be a bit better with a somewhat larger reflector. A brief description and picture of the 70 cm reflector is in the November/December 2005 Amsat Journal article on The Development of a Quarter Wave Match for helical antennas. Clare VE3NPC Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU ___ 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] WD9EWK @ DM44xj/DM54aj now
Hi! I found a spot on the DM44/DM54 line for the passes starting with the AO7 pass at 2256 UTC through at least the SO50 pass at 0206 UTC. Hope to work you from here. 73! Patrick WD9EWK/VA7EWK - north of Show Low, Arizona http://www.wd9ewk.net/ ___ 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: HELIX REFLECTOR?
- Original Message - From: Pete Norris, K1HZU k1...@yahoo.com To: amsat-bb@amsat.org Sent: Friday, June 04, 2010 2:51 AM Subject: [amsat-bb] HELIX REFLECTOR? Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU Hi Pete, K1HZU My 15 turns RHCP 70 cm Helix Antenna was built at first with a round aluminum sheet perforated reflector with a diameter of 460 mm ( 0.67 wavelenght) and it worked very well but after enlarging the diameter of reflector to 690 mm (about 1 wavelenght) overlapping to it a perforated aluminum mesh I realized that the gain increases by about 2 dB and the front to back ratio was much better than before. The Helix is made with a non annealed wiredrawn aluminum rod 8 mm in diameter and the boom is made with a very hard plastic pipe 42 mm outside diameter and 31 mm inside diameter originally used for hight pressure oil ducts. Following ANTENNAS from John Kraus the lenght of a turn has been made 1 wavelenght long into free space and the pitch angle between turns is about 13.8 degrees while the calculated half-power beam width is about 28 degrees. The matching system between the 150 ohm impedance at the feed point and a 50 ohm coax cable is made using a 1/4 electrical wavelenght impedance transformer with Zo = 86 ohm made with two coaxial tubing. For better performance and not to distort the pattern the antenna is fastened to the rear of reflector and the weight is balanced with a counterweight made with few lead disks. The picture of the above 15 turns helix antenna is visible at i8CVS in QRZ.com I have built two Helix Antennas the first one is a 10 turns with 0.67 wavelenght round reflector used beginning from OSCAR-7 to actually FO-29 and HO-68 and it works very well. The second one is a 15 turns helix with a 1 wavelenght in diameter round reflector and it was used for the uplink from OSCAR-10 to AO40 as can be seen at i8CVS in QRZ.com but unfortunately I cannot use it for LEO satellites because the AZ/EL mount is slow because it was designed for HEO satellites and this is why I pull for P3E ! If someone is interested to built the above antenna for 10 or 15 turns I can send a zipped file with all the electrical and mechanical sized drawings of it. Best 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: Falcon 9 video - moving early?
SpaceX starts all nine engines and makes sure they are operating to spec before releasing the rocket from the pad. The shuttle does the same thing with the three shuttle engines before they light the solids. 73, Drew KO4MA -Original Message- From: vk1pe.peter vk1pe.pe...@gmail.com Sent: Jun 5, 2010 4:59 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Falcon 9 video - moving early? I think that my eyes are not deceiving me. See http://www.youtube.com/watch?v=sP5gykvTBpM or http://bit.ly/dx9Vot. Falcon 9 appears to move at about T -3s. The count is still running towards zero in the video, and the call seems to be between 4 and 3. What do others think? Also, were the umbilicals meant to tear away (as it moved) or drop away (before it moved)? Peter VK1PE ___ 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: Falcon 9 video - moving early?
yES BUT IN THAT VIDEO BELOW IT IS CLEASRLY OFF THE PAD AND MOVING UP AT T-3 SECONDS. The Original Rolling Ball Clock Idle Tyme Idle-Tyme.com http://www.idle-tyme.com On 6/5/2010 5:57 PM, Andrew Glasbrenner wrote: SpaceX starts all nine engines and makes sure they are operating to spec before releasing the rocket from the pad. The shuttle does the same thing with the three shuttle engines before they light the solids. 73, Drew KO4MA -Original Message- From: vk1pe.petervk1pe.pe...@gmail.com Sent: Jun 5, 2010 4:59 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Falcon 9 video - moving early? I think that my eyes are not deceiving me. See http://www.youtube.com/watch?v=sP5gykvTBpM or http://bit.ly/dx9Vot. Falcon 9 appears to move at about T -3s. The count is still running towards zero in the video, and the call seems to be between 4 and 3. What do others think? Also, were the umbilicals meant to tear away (as it moved) or drop away (before it moved)? Peter VK1PE ___ 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 ___ 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: Falcon 9 video - moving early?
--- On Sat, 6/5/10, Joe n...@mwt.net wrote: From: Joe n...@mwt.net Subject: [amsat-bb] Re: Falcon 9 video - moving early? To: amsat-bb@amsat.org Received: Saturday, June 5, 2010, 5:27 PM yES BUT IN THAT VIDEO BELOW IT IS CLEASRLY OFF THE PAD AND MOVING UP AT T-3 SECONDS. I noticed that as well, but, since I was watching this via webcast, what I saw might have been due to a lag between the video and audio feeds. 73s Bernhard VA6BMJ @ DO33FL ___ 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: Falcon 9 video - moving early?
--- On Sat, 6/5/10, Andrew Glasbrenner glasbren...@mindspring.com wrote: From: Andrew Glasbrenner glasbren...@mindspring.com Subject: [amsat-bb] Re: Falcon 9 video - moving early? To: vk1pe.pe...@gmail.com, amsat-bb@amsat.org Received: Saturday, June 5, 2010, 4:57 PM SpaceX starts all nine engines and makes sure they are operating to spec before releasing the rocket from the pad. The shuttle does the same thing with the three shuttle engines before they light the solids. snip That's been the case even earlier as well. Listen to any of the countdowns for the Apollo lunar missions. The Saturn V's engines would ignite at about T-9 and take a few seconds to produce full thrust before lift-off at T = 0. If I'm not mistaken, in the very early days, T (or, as it was originally called X) = 0 was when actual ignition occurred, so lift-off was 2 or 3 seconds later. 73s Bernhard VA6BMJ @ DO33FL ___ 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: Re HELIX REFLECTOR?
Hi Steve, To avoid giving you bad info, I went back and looked at some of the modeling I did a few years ago to refresh my memory and realized that was done on crossed yagis and not helixes. Recently I did some helix modeling and took some field measurements on a terrestrial sectored antenna application and found that I could not get the F/B any greater than 20 dB without a backplane that was at least 1 wavelength in diameter and with a forward-flared rim at the end (like the lip of a screw top). Since you asked the question, however, I went back and looked at the model again. Perhaps the word adversely was a bit of an exaggeration. In the vertical orientation (at 437 MHz), the forward gain of the main lobe didn't change much between 1 and 5 wavelengths above ground; what did change was the depth of the off axis nulls. More pronounced (of course) is during the transition from vertical to horizontal, the ground reflections raise the pointing angle of the main lobe to as high as 15 degrees off axis at horizontal when the antenna is as low as 1 wavelength above ground. Bottom line, 1 wavelength I guess. But not so much because of a degradation in forward gain but because the angle of the main lobe is off axis. Hope this is helpful and not just a rambling. John On Jun 5, 2010, at 2:10 PM, STeve Andre' wrote: john, whats a good rule for height of the antennas to avoid large back lobes reflecting, ie how many wavelengths up should the antennas be? Thanks... --STeve Andre' wb8wsf en82 On Saturday 05 June 2010 17:07:15 John Belstner wrote: Just another $0.02 to add. You will find that the size and shape of the reflector will not affect the forward gain as much as it does the F/B ratio. It depends on what is important to you and (of course) how high you are above the ground. Even for satellite operation pointing up, large back lobes reflecting off the ground can adversely affect the forward pattern when the antenna is mounted only 6-8 feet above ground. On Jun 4, 2010, at 10:13 PM, Clare Fowler wrote: To add to the discussion the July/Aug 2007 Amsat Journal has an article covering some gain comparisonmeasurements I made between four 13 turn (2.88 wavelengths) 13cm antennas with different square solid aluminum reflectors. The sizes were 0.56 wavelengths, 0.84 wavelengths, 1.0 wavelength and 1.4 wavelengths. There was no difference between the 0.84, 1.0 and 1.4 wavelengths but the antenna with the0.56 wavelength reflector had 1.5 db less gain. However for my 70cm helix antennas I followed the Satellite Handbook minimum size of 0.6 wavelengthsor slightly over 16 inches. I used 1/2 inch hardware cloth mesh to keep the weight and windloading down. These antennas have performed well however it appears that they would be a bit better with a somewhat larger reflector. A brief description and picture of the 70 cm reflector is in the November/December 2005 Amsat Journal article on The Development of a Quarter Wave Match for helical antennas. Clare VE3NPC Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU ___ 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] HELIX REFLECTOR
- Original Message - From: Pete Norris, K1HZU k1...@yahoo.com To: amsat-bb@amsat.org Sent: Friday, June 04, 2010 2:51 AM Subject: [amsat-bb] HELIX REFLECTOR? Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU Hi Pete, K1HZU My 15 turns RHCP 70 cm Helix Antenna was built at first with a round aluminum sheet perforated reflector with a diameter of 460 mm ( 0.67 wavelenght) and it worked very well but after enlarging the diameter of reflector to 690 mm (about 1 wavelenght) overlapping to it a perforated aluminum mesh I realized that the gain increases by about 2 dB and the front to back ratio was much better than before. The Helix is made with a non annealed wiredrawn aluminum rod 8 mm in diameter and the boom is made with a very hard plastic pipe 42 mm outside diameter and 31 mm inside diameter originally used for hight pressure oil ducts. Following ANTENNAS from John Kraus the lenght of a turn has been made 1 wavelenght long into free space and the pitch angle between turns is about 13.8 degrees while the calculated half-power beam width is about 28 degrees. The matching system between the 150 ohm impedance at the feed point and a 50 ohm coax cable is made using a 1/4 electrical wavelenght impedance transformer with Zo = 86 ohm made with two coaxial tubing. For better performance and not to distort the pattern the antenna is fastened to the rear of reflector and the weight is balanced with a counterweight made with few lead disks. The picture of the above 15 turns helix antenna is visible at i8CVS in QRZ.com I have built two Helix Antennas the first one is a 10 turns with 0.67 wavelenght round reflector used beginning from OSCAR-7 to actually FO-29 and HO-68 and it works very well. The second one is a 15 turns helix with a 1 wavelenght in diameter round reflector and it was used for the uplink from OSCAR-10 to AO40 as can be seen at i8CVS in QRZ.com but unfortunately I cannot use it for LEO satellites because the AZ/EL mount is slow because it was designed for HEO satellites and this is why I pull for P3E ! If someone is interested to built the above antenna for 10 or 15 turns I can send a zipped file with all the electrical and mechanical sized drawings of it. Best 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] Fw: WD9EWK @ DM44xj/DM54aj now
- Original Message - From: Patrick STODDARD amsat...@wd9ewk.net To: amsat-bb@amsat.org Sent: Sunday, June 06, 2010 12:35 AM Subject: [amsat-bb] WD9EWK @ DM44xj/DM54aj now Hi! I found a spot on the DM44/DM54 line for the passes starting with the AO7 pass at 2256 UTC through at least the SO50 pass at 0206 UTC. Hope to work you from here. 73! Patrick WD9EWK/VA7EWK - north of Show Low, Arizona http://www.wd9ewk.net/ ___ 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 HELIX REFLECTOR?
Hi John, I agree with you. I have in my hands the book RADIO ASTRONOMY by John Kraus ISBN 07-035392-1 This is the text of page-200 An example of a partially steerable (meridian transit) array antenna is presented in Fig.6-41 This antenna,built in 1952 at the Ohio State University radio observatory, consists of an array of 96 helical-beam antennas, each of 11 turns, mounted on a tiltable steel grounded ground plane 160 ft long (east-west) by 22 ft wide. At a wavelenght of 1.2 meters the beam width measured 1 degree in right ascension by 8 degrees in declination. My comment: As seen from the photograph 6.41 the tiltable steel ground plane seems to be mounted at no more than 10 to 12 ft from the ground so that when the reflector is very large it seems that the high of it from the ground is not very important both for gain and front to back ratio. In this array the tiltable steel ground plane is 160 ft long and 22 ft wide with 24 helices in the longer side and 4 line of helices in the wide side (24 x 4 = 96 helices) so that the total ground plane area is 160 x 22 = 3520 square foot and each helix reflector takes 3520 / 96 = 37 square foot or about a square surface of 6 x 6 foot or a round area of 3.4 square meters with a diameter of 2.08 meters. Since the operating wavelenght of the radiotelescope is 1.2 meters the reflector diameter for each helix antenna has been made large 2.08 / 1.2 = 1.73 wavelenght and probably this is why a tiltable steel ground plane made so large can be mounted very close to the ground surface without affecting gain, front to back ratio and without to take too much noise at 290 kelvin from the ground. 73 de i8CVS Domenico - Original Message - From: John Belstner jbelst...@yahoo.com To: Clare Fowler clarefow...@rogers.com Cc: amsat-bb amsat-bb@amsat.org Sent: Saturday, June 05, 2010 11:07 PM Subject: [amsat-bb] Re: Re HELIX REFLECTOR? Just another $0.02 to add. You will find that the size and shape of the reflector will not affect the forward gain as much as it does the F/B ratio. It depends on what is important to you and (of course) how high you are above the ground. Even for satellite operation pointing up, large back lobes reflecting off the ground can adversely affect the forward pattern when the antenna is mounted only 6-8 feet above ground. On Jun 4, 2010, at 10:13 PM, Clare Fowler wrote: To add to the discussion the July/Aug 2007 Amsat Journal has an article covering some gain comparisonmeasurements I made between four 13 turn (2.88 wavelengths) 13cm antennas with different square solid aluminum reflectors. The sizes were 0.56 wavelengths, 0.84 wavelengths, 1.0 wavelength and 1.4 wavelengths. There was no difference between the 0.84, 1.0 and 1.4 wavelengths but the antenna with the0.56 wavelength reflector had 1.5 db less gain. However for my 70cm helix antennas I followed the Satellite Handbook minimum size of 0.6 wavelengthsor slightly over 16 inches. I used 1/2 inch hardware cloth mesh to keep the weight and windloading down. These antennas have performed well however it appears that they would be a bit better with a somewhat larger reflector. A brief description and picture of the 70 cm reflector is in the November/December 2005 Amsat Journal article on The Development of a Quarter Wave Match for helical antennas. Clare VE3NPC Hi All: I am rebuilding a 440 MHZ Helix that I built several years ago . It worked very well, but I would like to reduce the size of the reflector to a more manageable size than I had before. The only reference to reflector size I can find is, minimum 20 . I may be looking in the wrong places. I would appreciate it, if someone would steer me in the right direction. Thanks, Pete, K1HZU ___ 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: FIELD DAY SCORING
Pete Bruce, Good to know about the LINEAR birds. The rules are still different, AMSAT will allow one V/U and one V/S contact on AO-51. The ARRL will only allow one contact on AO-51. 73, Joe kk0sd -Original Message- From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On Behalf Of Bruce Sent: Saturday, June 05, 2010 10:13 AM To: Peter Portanova Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: FIELD DAY SCORING That should make it much easier for everyone as you don't have to do one log and then strip out the unwanted calls for the other. Thanks Pete. I am glad that the two minds (ARRL and AMSAT) have become one. 73...bruce From: Peter Portanova r...@optonline.net To: amsaT-BB@amsat.org Sent: Sat, June 5, 2010 9:33:07 AM Subject: [amsat-bb] FIELD DAY SCORING Hello, I was in contact with the ARRL, after I read 7.3.7. and 7.3.7.1. in the Field Day Rules. I mentioned to the League that I would like them to point out where in those rules it would prohibit scoring the same call on multiple Linear Satellites. They listened to my point's and agreed that even though the rules refer to satellite contacts as a separate band there is nothing in those rules that prohibit the aforementioned scoring. In conclusion Field Day and the AMSAT scoring are now in agreement, have fun. 73's Pete WB2OQQ www.massapequanyweather.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] WD9EWK on the move tomorrow to DM56
Hi! Thanks to all the stations that worked me today, at the White Mountain Hamfest in Show Low and later in the day at DM44xj/DM54aj north of Show Low. WD9EWK logged 41 QSOs at the hamfest (including an amazing 12 QSOs on one AO7 pass around 1400 UTC!), followed by 47 more at the grid boundary. I hope to be up at DM56 Sunday morning for the 1620 UTC SO50 pass. I may be able to park on the DM55/DM56 line, but the primary goal for the day is DM56. I'll work passes on SO50, VO52, HO68, AO27, plus an AO51 pass just before 2300 UTC. Tomorrow will be a busy driving day - about 3 hours from here up to DM56, then 5 hours or so from DM56 back home. With the long drive home, I can't stay in DM56 for the passes after 2300 UTC nor do I plan to stop for any passes that I could work in the evening. I hope to work a bunch of you tomorrow from one of the rarely-heard grids in Arizona. 73! Patrick WD9EWK/VA7EWK - Pinetop-Lakeside, Arizona http://www.wd9ewk.net/ ___ 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
