Topband: Radials - open ended or tied together in a grid qrrtangement??
I wonder if there is supporting analysis for connecting the radial ends?? I have around 80 elevated radials that range from 50 foot lengths, running east and west, and 25 foot lengths running north and south (all of that a function of being geographically challenged). I have not tied the bitter ends togethernever really thought about it when I put the radial field together but seem to recall reading something about tieing the ends together and having a well bounded complete grid underthe antenna. Thoughts? I tend to think it wouldn't hurt... 72, Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: j...@audiosystemsgroup.com; 'TopBand' topband@contesting.com Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what lowest loss means? At least that was my intention. I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: Jim Brown j...@audiosystemsgroup.com To: 'TopBand' topband@contesting.com Sent: Saturday, February 15, 2014 12:15 AM Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 7:00 PM, Charlie Cunningham wrote: All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. If you run the equations, you find that below about 1 GHz, the losses are all copper losses. Dielectric loss is a few percent of the total loss in the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that it allows the center conductor to be larger for a given shield diameter. But the improvement in loss of a foam dielectric coax below 1 GHz is entirely due to the center conductor being larger. BTW -- the relevant equation is on each Times data sheet. 73, Jim K9YC Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Top of Form Set Parameters as Desired Line Type: Line Length: Feet Meters Frequency: MHz Load SWR: : 1 Power In: W Bottom of Form Top of Form Results Matched Loss: dB SWR Loss: dB Total Loss: dB Power Out: W Bottom of Form Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250 of RG-8 of 0.606 dB Note the flat-loss or matched loss of the cable (at 1:1 VSWR) is 0.577 dB. So theres no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250 of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90 the tower heard very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you tap at 90 and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a spark gap and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial ring and the end of the gamma wire with no fluctuations so I'm confident that I have good continuity throughout the tower. Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted at the (4) points on the tower that are available... With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of the drop wire on the MFJ At all of these points I was able to knock down the R with my honkin' 1050pf cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has indicated, I should be able to find a 50 ohm tap somewhere on the tower. I can't find it. When I had the gamma arm mounted at the 90' level. I was able to put my baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and the antenna heard very well; especially on the 1700 KHz broadcast band, with a 2.4:1 Vswr. Similar results could be seen at the other levels too as long as I brought the R down with a variable cap. Yesterday, with the gamma arm at the 46' level (and 240 ohms on the MFJ) I was able to put the big variable inline to bring the reading to 24 ohms with a TRUE X=0. With a 22 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on the output of the UNUN. I worked a W2 in NJ and a W4 in Florida with just the 1000D.
Re: Topband: Palomar R-X Noise Bridge
I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance. 73, Charlie, K4OTV -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: j...@audiosystemsgroup.com; 'TopBand' topband@contesting.com Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what lowest loss means? At least that was my intention. I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Do tell! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Saturday, February 15, 2014 11:05 AM To: j...@audiosystemsgroup.com; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge - Original Message - From: Jim Brown j...@audiosystemsgroup.com To: 'TopBand' topband@contesting.com Sent: Saturday, February 15, 2014 12:15 AM Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 7:00 PM, Charlie Cunningham wrote: All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. If you run the equations, you find that below about 1 GHz, the losses are all copper losses. Dielectric loss is a few percent of the total loss in the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that it allows the center conductor to be larger for a given shield diameter. But the improvement in loss of a foam dielectric coax below 1 GHz is entirely due to the center conductor being larger. BTW -- the relevant equation is on each Times data sheet. 73, Jim K9YC Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Carl: I've read, at several places, that sleeve baluns are effective at VHF and above but not at HF frequencies..thoughts?? 72/73, Jim Rodenkirch --- former Tempest inspector for the U.S. Navy..ah...Tempest comcerns - the good 'ol days hi Hi! From: charlie-cunning...@nc.rr.com To: k...@jeremy.mv.com; topband@contesting.com Date: Sat, 15 Feb 2014 11:39:14 -0500 Subject: Re: Topband: Palomar R-X Noise Bridge I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance. 73, Charlie, K4OTV -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: j...@audiosystemsgroup.com; 'TopBand' topband@contesting.com Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what lowest loss means? At least that was my intention. I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Sorry, Carl! My loss tables didn't translate from HTML to the reflector. I'll re-build the tables manually and re-send this message! Sorry! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: Re: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Top of Form Set Parameters as Desired Line Type: Line Length: Feet Meters Frequency: MHz Load SWR: : 1 Power In: W Bottom of Form Top of Form Results Matched Loss: dB SWR Loss: dB Total Loss: dB Power Out: W Bottom of Form Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250 of RG-8 of 0.606 dB Note the flat-loss or matched loss of the cable (at 1:1 VSWR) is 0.577 dB. So theres no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250 of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90 the tower heard very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you tap at 90 and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a spark gap and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial ring and the end of the gamma wire with no fluctuations so I'm confident that I have good continuity throughout the tower. Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted at the (4) points on the tower that are available... With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of the drop wire on the MFJ At all of these points I was able to knock down the R with my honkin' 1050pf cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has indicated, I should be able to find a 50 ohm tap somewhere on the tower. I can't find it. When I had the gamma arm mounted at the 90' level. I was able to put my baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and the antenna heard very well; especially on the 1700 KHz broadcast band, with a
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Hi, Jim Well, Maxwell's W2DU balu ns are ferrite sleeve baluns and you can get those that go down to 160m. It's a matter of choosine the right ferrite for the frequenc;y range of interest, and using enough ferrite to build p the common-mode impedance! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Saturday, February 15, 2014 11:45 AM To: 'Carl Braun'; '160' Subject: Re: Topband: Still in search of resonance - Detailed Observations and Calculations Sorry, Carl! My loss tables didn't translate from HTML to the reflector. I'll re-build the tables manually and re-send this message! Sorry! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: Re: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Top of Form Set Parameters as Desired Line Type: Line Length: Feet Meters Frequency: MHz Load SWR: : 1 Power In: W Bottom of Form Top of Form Results Matched Loss: dB SWR Loss: dB Total Loss: dB Power Out: W Bottom of Form Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250 of RG-8 of 0.606 dB Note the flat-loss or matched loss of the cable (at 1:1 VSWR) is 0.577 dB. So theres no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250 of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90 the tower heard very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you tap at 90 and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a spark gap and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial ring and the end of the gamma wire with no fluctuations so I'm confident that I have good continuity throughout the tower. Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted at the (4) points on the tower that are available... With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 28' and 36
Re: Topband: Palomar R-X Noise Bridge
Hi, Jim Well, Maxwell's W2DU balu ns are ferrite sleeve baluns and you can get those that go down to 160m. It's a matter of choosine the right ferrite for the frequenc;y range of interest, and using enough ferrite to build p the common-mode impedance! 73, Charlie, K4OTV From: James Rodenkirch [mailto:rodenkirch_...@msn.com] Sent: Saturday, February 15, 2014 11:45 AM To: Charlie Cunningham; 'Carl'; Top Band Contesting Subject: RE: Topband: Palomar R-X Noise Bridge Carl: I've read, at several places, that sleeve baluns are effective at VHF and above but not at HF frequencies..thoughts?? 72/73, Jim Rodenkirch --- former Tempest inspector for the U.S. Navy..ah...Tempest comcerns - the good 'ol days hi Hi! From: charlie-cunning...@nc.rr.com To: k...@jeremy.mv.com; topband@contesting.com Date: Sat, 15 Feb 2014 11:39:14 -0500 Subject: Re: Topband: Palomar R-X Noise Bridge I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance. 73, Charlie, K4OTV -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: j...@audiosystemsgroup.com; 'TopBand' topband@contesting.com Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what lowest loss means? At least that was my intention. I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. That has nothing at all to do with dielectric losses. N connectors have a tiny BNC size center pin. RG-213 have a woven braid and stranded center conductor making the small center conductor diameter heating and shield heating even worse. Jim is correct. Conductor losses significantly dominate dielectric losses at UHF and lower to the point where dielectric loss is meaningless. There are exceptions, of course, but not with normal parts. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. The lowest loss cables have large, smooth conductors that are the maximum possible size for the cable impedance. Dielectric is largely meaningless, except as it might affect conductor size. We can argue this point endlessly, but it will always come back to the conductors. The exception would be some horrible dielectric or operation way up above normal VHF/UHF with marginal dielectrics. It is the way it is. The confusion probably occurs because dielectrics with more air allow a larger conductor to be used for a given cable diameter and impedance, it is not because the dielectric has less loss. _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: FW: Still in search of resonance - Detailed Observations and Calculations
Well, here it is with the re-built loss table, Carl 73, Charlie, K4OTV From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: RE: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Line/Load Line type:Belden 8237 RG8 Line length 250 Frequency 1.8 MHz Load SWR1.4:1 Power In 100W Results: Matched Loss: 0.577 dB SWR Loss 0.029 dB Total Loss0.606 dB Power Out 86.982 W Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250 of RG-8 of 0.606 dB Note the flat-loss or matched loss of the cable (at 1:1 VSWR) is 0.577 dB. So theres no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250 of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90 the tower heard very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you tap at 90 and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a spark gap and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial ring and the end of the gamma wire with no fluctuations so I'm confident that I have good continuity throughout the tower. Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted at the (4) points on the tower that are available... With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of the drop wire on the MFJ At all of these points I was able to knock down the R with my honkin' 1050pf cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has indicated, I should be able to find a 50 ohm tap somewhere on the tower. I can't find it. When I had the gamma arm mounted at the 90' level. I was able to put my baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and the antenna heard very well;
Topband: Radials - open ended or tied together in a gridqrrtangement??
Jim, Think of a cage connection rather than a single wire to a shunt fed tower and its benefit. The cage larger diameter causes an impedance change and also makes it a more broad-banded fat conductor. Benefits of a in ground grid have been established. A partial grid connected to radials already in place would not be a negative. Antennas that are fat the entire length have a lower Q, lower impedance at the far end, and are wider in frequency. I think of my in ground radial system system in a similar fashion. My ground radial system has a perimeter wire and has worked well. Working in the DX contest this weekend on 160 meters with 100 watts. Only a few request for a call repeat. The best benefit of a perimeter wire : ... It allows each wire to be individually disconnected at the tower base. The disconnected wire can be checked with an ohmmeter against the remaining radials to confirm continuity. I check them every few years, and pull any broken wires up to splice or replace. 73 Bruce-K1FZ www.qsl.net/k1fz/beveragenotes.html I wonder if there is supporting analysis for connecting the radial ends?? I have around 80 elevated radials that range from 50 foot lengths, running east and west, and 25 foot lengths running north and south (all of that a function of being geographically challenged). I have not tied the bitter ends togethernever really thought about it when I put the radial field together but seem to recall reading something about tieing the ends together and having a well bounded complete grid underthe antenna. Thoughts? I tend to think it wouldn't hurt... 72, Jim Rodenkirch K9JWV _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Carl: I've read, at several places, that sleeve baluns are effective at VHF and above but not at HF frequencies..thoughts?? 72/73, Jim Rodenkirch --- former Tempest inspector for the U.S. Navy..ah...Tempest comcerns - the good 'ol days hi Hi! Oh, the fun we had almost living in a screen room in order to get a product past those inspectors!! The effect of shielding and ferrites has been permanently imprinted on my brain. I sometimes have to laugh when reading that some consider a sleeve balun/choke to be a recent invention! Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We started with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Carl KM1H From: charlie-cunning...@nc.rr.com To: k...@jeremy.mv.com; topband@contesting.com Date: Sat, 15 Feb 2014 11:39:14 -0500 Subject: Re: Topband: Palomar R-X Noise Bridge I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance. 73, Charlie, K4OTV -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: j...@audiosystemsgroup.com; 'TopBand' topband@contesting.com Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge All generally true, I expect, but I also believe that dielectric constant and dielectric losses also figure in and the lowest loss lines would be filled with air, dry nitrogen or evacuated. I expect those would likely be the lowest loss AND highest velocity factor cases. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Friday, February 14, 2014 9:42 PM To: 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge On 2/14/2014 2:17 PM, Carl wrote: Isnt that what lowest loss means? At least that was my intention. I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it. You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf. Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: In search of resonance
When using a gamma match you are usually going up on the tower beyond the 50 ohm point. From that point down the gamma rod and the tower is acting like a parallel wire transmission rod, transforming that impedance down to a lower value, hopefully near 50. You will see the 50 ohm R plus inductive reactance at the feed point. The series gamma capacitor tunes out the inductive reactance leaving just the R. The way to change the R is with a shunt capacitor (as in an Omega match) the series capacitor only compensates for the series inductance. I do not think taking a reading at the bottom of the gamma wire with the MFJ is giving a valid R value, especially since adding a series capacitor seems to change the R. Matching a tower with a gamma match is just like matching a Yagi with a gamma rod. If the bottom of the tower (center of the Yagi element) has an impedance of Z then a point up the tower or out on the Yagi element X degrees will be Z divided by (cosine X) squared. ( plus a factor due to unequal diameters of the element and gamma rod must also be considered) For example if the base of the tower is 35 ohms, moving up 30 degrees (40 some feet) will give a Z at that point of about 45 ohms. But the gamma rod and the tower act like a step up transformer. Remember how a folded dipole works. Two same size wires will give a step up of 4 times what a single wire has. Single wire dipole 75 ohms and folded dipole 300 ohms. If the wires are not the same the ratio is different. In the case of the tower being larger than the gamma wire, the ratio is much higher. So the Z at the top end of the gamma will be several times higher. I usually guess this number and plot on a Smith chart. Then move around x degrees. This brings me to some value of R and inductive X. Then the gamma Capacitor tunes out the inductive reactance. Measuring this with the MFJ 259 should give good results. If the reading is like 100 ohms you can make the gamma rod shorter, bringing down the R. If low, make the gamma rod longer. (I may have this just reversed, again, I like to use a Smith chart because it is easy to see what happens when one parameter is changed. It can be very confusing otherwise and I am relying on only my old memory as I write this) I know some of the old ARRL antenna books have good info on designing gamma matches. For all my towers I have gotten close enough with a #12 wire about 20 to 30 foot long about 18 inches off the tower. One other easy method that seems to always work is to come down to an L network. I have used a slant feed wire running from an L network on the ground up at a 30 to 45 degree angle to a tap on the tower. That particular installation was a Rohn 45 tower at 70 ft top loaded with a full size 4 element 20 meter monobander. The shunt C on the output of the L network changes the R and the coil compensates for the reactance. Remember shunt element changes the R and the series element does not change the real R. Sometimes you have to turn the L network around because you want the shunt C on the high impedance side. 73, Don N4DJ Sent from my iPad _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: Tom W8JI w...@w8ji.com To: 'TopBand' topband@contesting.com Sent: Saturday, February 15, 2014 12:08 PM Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1 General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. The lowest loss cables have large, smooth conductors that are the maximum possible size for the cable impedance. Dielectric is largely meaningless, except as it might affect conductor size. ** Which directly affects loss. While meaningless at 160 even in long runs the difference between the 1 Fused Disc and 1 solid foam Commscope is .5 vs .65dB/100' at 222 MHz which can add up to no contact in long lengths. We can argue this point endlessly, but it will always come back to the conductors. ** As close to an air dielectric as possible will have the largest diameter center conductor and lowest loss. Adding any other dielectric requires a smaller conductor to maintain the same impedance and with its own extra loss caused by the dielectric choice so it will always be a contributing factor since its dielectric constant and capacitance per foot varies and is not a lossless medium. It is also frequency sensitive. A nitrogen pressurized coax is about as good as it gets. The exception would be some horrible dielectric or operation way up above normal VHF/UHF with marginal dielectrics. It is the way it is. The confusion probably occurs because dielectrics with more air allow a larger conductor to be used for a given cable diameter and impedance, it is not because the dielectric has less loss. ** Im not confused but for the sake of the forum it is not exactly related to 160 so lets leave it for elsewhere. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Charlie Thank you for your work and insight. It appears I've I may have provided some incorrect info. When I tapped the tower at 90' I used the 160pf variable cap to get down to the 68 ohm impedance measurement and, yes, it heard well with what appeared to be a peak at approx 1770kc I never transmitted there. I've only transmitted with the system when I had a tap at 46' where I saw 24 ohms and X=0 with the variable. Ap on series. Then I installed a 22 to 50 ohm Unun and made the contacts to east coast stations. I believe I have plenty of capacitance on hand if I tap the tower at 90' but given the 68 ohm reading at 90' with the variable cap and the 24 ohm reading at 46' with the variable cap don't you think the best bet would be my 67' tap point? Even if it's still a bit low in resistance at that point i could add a bit of parallel C in conjunction with the series C to bring the antenna to 50 ohms+j0? Please advise and thank you for the most enjoyable technical conversation. Carl AG6X Sent from my iPhone On Feb 15, 2014, at 9:14 AM, Charlie Cunningham charlie-cunning...@nc.rr.commailto:charlie-cunning...@nc.rr.com wrote: Well, here it is with the re-built loss table, Carl 73, Charlie, K4OTV From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: RE: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Line/Load Line type:Belden 8237 RG8 Line length 250’ Frequency 1.8 MHz Load SWR1.4:1 Power In 100W Results: Matched Loss: 0.577 dB SWR Loss 0.029 dB Total Loss0.606 dB Power Out 86.982 W Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250’ of RG-8 of 0.606 dB Note the “flat-loss” or “matched loss” of the cable (at 1:1 VSWR) is 0.577 dB. So there’s no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250’ of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90’ the tower “heard” very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you “tap” at 90’ and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a “spark gap” and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Charlie FYI. I'm using 60' to 70' of LMR400 from my panel at the base of the needle to the shack. No long runs here. Carl AG6X Sent from my iPhone On Feb 15, 2014, at 9:14 AM, Charlie Cunningham charlie-cunning...@nc.rr.commailto:charlie-cunning...@nc.rr.com wrote: Well, here it is with the re-built loss table, Carl 73, Charlie, K4OTV From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: RE: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Line/Load Line type:Belden 8237 RG8 Line length 250’ Frequency 1.8 MHz Load SWR1.4:1 Power In 100W Results: Matched Loss: 0.577 dB SWR Loss 0.029 dB Total Loss0.606 dB Power Out 86.982 W Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250’ of RG-8 of 0.606 dB Note the “flat-loss” or “matched loss” of the cable (at 1:1 VSWR) is 0.577 dB. So there’s no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250’ of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90’ the tower “heard” very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you “tap” at 90’ and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a “spark gap” and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 14, 2014 6:15 PM To: '160' Subject: Topband: Still in search of resonance List Some of you may have followed my efforts in trying to shunt feed my 90' Tri-Ex Skyneedle with 20 meter yagi at 93'. I'm still unable to find any sort of resonance point on the tower. To refresh everyone's memory here are the specifics: 90' Skyneedle that is 12 round at the base and 4 round at the top 13' of mast out the top 5 element Telrex 20M monobander mounted at the 93' level. No other antennas on the tower 1 ½ copper pipe as a radial ring that surrounds the concrete base that measures 4' x 8' rectangle. Three 8' ground rods are connected to the radial ring via 1 copper strap that is .125 thick. Currently I have 27 14AWG insulated wire radials. Most of the radials are 20' to 50' long with three at 90 to 120' long and four of them connected to my 40M vertical array which have 100 count radials 50' to 100' each. The tower is grounded to each ground rod via 1 copper strap .125 thick and, as mentioned above, the ground rods are connected to the radial ring with the same strap with copper clad stainless screws. When I bolted the gamma arm to the tower at the 90' height I dropped a single 14AWG wire to the ground where my FLUKE meter read ZERO ohms between the radial ring and the end of the gamma wire with no fluctuations so I'm confident that I have good continuity throughout the tower. Here are the readings that I saw on the MFJ analyzer with the gamma arm mounted at the (4) points on the tower that are available... With the gamma arm mounted at 90' and 36 spacing I saw 425 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 67' and 36 spacing I saw 380 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 46' and 36 spacing I saw 240 ohms at the end of the drop wire on the MFJ With the gamma arm mounted at 28' and 36 spacing I saw 120 ohms at the end of the drop wire on the MFJ At all of these points I was able to knock down the R with my honkin' 1050pf cap to some resonance sort of resonance at 1.825 MHz but, as most everyone has indicated, I should be able to find a
Re: Topband: Still in search of resonance - Detailed Observations and Calculations
Thanks, Carl! Well, if you' heard a RX peak at 1770 KHz, it seems that you are awfully close! Just needs a little careful tweaking I would think. (I ass'ume that you are probably shootinf for something around 1830 KHz. BTW - the higher you tap on the tower, the smaller the series capacitor needs to be, since the increasing series inductive reactance will require increasing capacitive reactance (lower C) to cancel it, so it sounds like you can use the 160 pF capacitor for your series tuning C. I haven't used my MFJ 259 in a while, so I would need to get it out and review its operation but when you tuned down to 68 ohms impedance whtn tapped at 90', I expect that's where the impedance became pure real at 68 ohms. As an additional check you can drive the gamma wire with a little power from your TX or the MFJ and tune the series capacitor for minimum SWR. Sounds like it should come in around 1.4. If it does, you're done. Just bolt everything down and enjoy. Clearly, if the 46' tap pointis showing24 ohms real that's way too low on the tower for your tap point! It sound like90]isprobably the point you want! GL, Carl! Have fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Saturday, February 15, 2014 3:11 PM To: Charlie Cunningham Cc: topband@contesting.com Subject: Re: Topband: Still in search of resonance - Detailed Observations and Calculations Charlie Thank you for your work and insight. It appears I've I may have provided some incorrect info. When I tapped the tower at 90' I used the 160pf variable cap to get down to the 68 ohm impedance measurement and, yes, it heard well with what appeared to be a peak at approx 1770kc I never transmitted there. I've only transmitted with the system when I had a tap at 46' where I saw 24 ohms and X=0 with the variable. Ap on series. Then I installed a 22 to 50 ohm Unun and made the contacts to east coast stations. I believe I have plenty of capacitance on hand if I tap the tower at 90' but given the 68 ohm reading at 90' with the variable cap and the 24 ohm reading at 46' with the variable cap don't you think the best bet would be my 67' tap point? Even if it's still a bit low in resistance at that point i could add a bit of parallel C in conjunction with the series C to bring the antenna to 50 ohms+j0? Please advise and thank you for the most enjoyable technical conversation. Carl AG6X Sent from my iPhone On Feb 15, 2014, at 9:14 AM, Charlie Cunningham charlie-cunning...@nc.rr.commailto:charlie-cunning...@nc.rr.com wrote: Well, here it is with the re-built loss table, Carl 73, Charlie, K4OTV From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Saturday, February 15, 2014 11:35 AM To: 'Carl Braun'; '160' Subject: RE: Topband: Still in search of resonance - Detailed Observations and Calculations Hi, Carl I did a bit of further investigation and work on your problem. I think you are done, as follows: 1.0 Just tap the Skyneedle at 90' and tune out the series inductive reactance with a variable capacitor, leaving you with 68 ohms real at the bottom of your drop wire. Great match! VSWR on 50 ohm feed cable of 1.4:1. 2.0 Now, let's assume you have 250 feet of Belden 8237 (RG-8) feeding the bottom of the drop wire. Losses are as follows: Line/Load Line type:Belden 8237 RG8 Line length 250 Frequency 1.8 MHz Load SWR1.4:1 Power In 100W Results: Matched Loss: 0.577 dB SWR Loss 0.029 dB Total Loss0.606 dB Power Out 86.982 W Note that the excess loss due to the SWR on the cable is 0.029 dB, out of a total loss in 250 of RG-8 of 0.606 dB Note the flat-loss or matched loss of the cable (at 1:1 VSWR) is 0.577 dB. So theres no real point in struggling to get to exactly 50 ohms real at the bottom of your drop-wire to recover 0.029 dB of loss in 250 of cable! Your 68 ohms is just fine! Just match tle line at the transmitter end and accept the modest 1.4:1 VSWR at the load end. As you observed, when tapped at 90 the tower heard very well and you made some contacts with your FT-1000D barefoot. So, it surely appears that you have a very good, well-matched antenna when you tap at 90 and tune out the series inductance of the gamma match in the normal way using a series capacitor. Just tune for X=0 at th bottom of the drop wire, connect the feedline and match the feedline at the transmitter and enjoy!! Of course, with a tower that tall, you probably want a spark gap and/or a gas-tube at the feed-point and sopme sortof static bleed to defend agains static charge and lightning! GL! Have fun! 73. Charlie, K4OTV
Re: Topband: Still in search of resonance
Tom After reading your post yesterday I had a dream that I woke up and saw one of those flying monkeys on top of my tower laughing and sawing away. Carl AG6X -Original Message- From: Tom W8JI [mailto:w...@w8ji.com] Sent: Friday, February 14, 2014 6:02 PM To: Carl Braun; '160' Subject: Re: Topband: Still in search of resonance Hi Carl, It sounds like you are trying to find 50 ohms on the tower without any series capacitor by looking at R and X. I would not try to do that. The reactance puts you out of range on the MFJ bridge. You are down to a few bits difference between data points the PIC needs in the MFJ. Look at this below. You said: seen at the other levels too as long as I brought the R down with a variable cap. Yesterday, with the gamma arm at the 46' level (and 240 ohms on the MFJ) I was able to put the big variable inline to bring the reading to 24 ohms with a TRUE X=0. With a 22 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on the output of the UNUN. I worked a W2 in NJ and a W4 in Florida with just the 1000D. BUT...again...I'm bringing the R down with the capacitor...not finding 50 ohms anywhere on the tower Stop trying to find 50 ohms without the capacitor! Right now at 46 ft you were at 24 ohms with the capacitor. That should tell you and everyone on this reflector :-) that you are tapped too low now! Let's look at this in simple terms. Here is what you said: When I had the gamma arm mounted at the 90' level. I was able to put my baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and the antenna heard very well; especially on the 1700 KHz broadcast band, with a 2.4:1 Vswr. Similar results could be seen at the other levels too as long as I brought the R down with a variable cap. That is NORMAL. You will always need the capacitor. Always. The only way to eliminate the capacitor is to saw your Yagi antenna off the tower so the tower moves above 2 MHz. Then you will probably find a 50j0 tap without any capacitor. You also might use a large skirt, but why?? Just use a capacitor!!! If you are trying to eliminate the capacitor, you will have a lot of work to do. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Still in search of resonance
Hee! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Saturday, February 15, 2014 3:53 PM To: Tom W8JI; '160' Subject: Re: Topband: Still in search of resonance Tom After reading your post yesterday I had a dream that I woke up and saw one of those flying monkeys on top of my tower laughing and sawing away. Carl AG6X -Original Message- From: Tom W8JI [mailto:w...@w8ji.com] Sent: Friday, February 14, 2014 6:02 PM To: Carl Braun; '160' Subject: Re: Topband: Still in search of resonance Hi Carl, It sounds like you are trying to find 50 ohms on the tower without any series capacitor by looking at R and X. I would not try to do that. The reactance puts you out of range on the MFJ bridge. You are down to a few bits difference between data points the PIC needs in the MFJ. Look at this below. You said: seen at the other levels too as long as I brought the R down with a variable cap. Yesterday, with the gamma arm at the 46' level (and 240 ohms on the MFJ) I was able to put the big variable inline to bring the reading to 24 ohms with a TRUE X=0. With a 22 ohm to 50 ohm UNUN, I saw 1.3:1 Vswr on the output of the UNUN. I worked a W2 in NJ and a W4 in Florida with just the 1000D. BUT...again...I'm bringing the R down with the capacitor...not finding 50 ohms anywhere on the tower Stop trying to find 50 ohms without the capacitor! Right now at 46 ft you were at 24 ohms with the capacitor. That should tell you and everyone on this reflector :-) that you are tapped too low now! Let's look at this in simple terms. Here is what you said: When I had the gamma arm mounted at the 90' level. I was able to put my baby variable 160pf inline to bring the 425 ohm impedance down to about 60 ohms and the antenna heard very well; especially on the 1700 KHz broadcast band, with a 2.4:1 Vswr. Similar results could be seen at the other levels too as long as I brought the R down with a variable cap. That is NORMAL. You will always need the capacitor. Always. The only way to eliminate the capacitor is to saw your Yagi antenna off the tower so the tower moves above 2 MHz. Then you will probably find a 50j0 tap without any capacitor. You also might use a large skirt, but why?? Just use a capacitor!!! If you are trying to eliminate the capacitor, you will have a lot of work to do. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Folded dipole vs gamma match
The step up ratio of a folded dipole occurs because the fed conductor extends parallel to the un-fed conductor for the entire length of the antenna. The element or element halves form 1/4 wave shorted stubs in differential excitation mode, but the current divides by ratios of effective diameters. The feedline, in effect, just samples a portion of the total current causing radiation. With a shunt feed system, the mechanism is different. The shorted stub formed by the gamma section is not 1/4 wave long, and parallels the feedpoint. Also, the gamma does not parallel the antenna length. There is actually not much change in the real part of impedance as the gamma rod changes ratio compared to element size. The slightly larger change is in reactance. For example, a 3 diameter gamma rod on a 1 inch diameter resonant 160 meter element at 40 feet produces an impedance of 289.6 + J 57.92 ohms Changing it to 0.1 inches results in 454.7 + J 130.7 ohms 130.7/57.92 = 2.26 ratio in reactance for a diameter ratio change of 30:1. 454.7/289.6 = 1.57 resistance ratio for the 30:1 change If I adjust the tap point to a good match (at 14 feet above ground) I have: 3 inch diameter gamma conductor 32.68 + J 65.45 ohms 0.1 inch gamma diameter 52.04 + J 111 ohms 1.6 ratio in resistance and 1.7 in reactance for a 30:1 change in rod diameter. The primary benefit in a larger diameter gamma rod is lower Q and lower voltage across the tuning capacitor. If I shorten the element, I can gamma match without a capacitor. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Folded dipole vs gamma match
All true, but I don't thnk Carl needs to shorten his tower or remove the yagi! I'd just use a series tuning capacitor! :-) Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 15, 2014 4:07 PM To: Topband Subject: Topband: Folded dipole vs gamma match The step up ratio of a folded dipole occurs because the fed conductor extends parallel to the un-fed conductor for the entire length of the antenna. The element or element halves form 1/4 wave shorted stubs in differential excitation mode, but the current divides by ratios of effective diameters. The feedline, in effect, just samples a portion of the total current causing radiation. With a shunt feed system, the mechanism is different. The shorted stub formed by the gamma section is not 1/4 wave long, and parallels the feedpoint. Also, the gamma does not parallel the antenna length. There is actually not much change in the real part of impedance as the gamma rod changes ratio compared to element size. The slightly larger change is in reactance. For example, a 3 diameter gamma rod on a 1 inch diameter resonant 160 meter element at 40 feet produces an impedance of 289.6 + J 57.92 ohms Changing it to 0.1 inches results in 454.7 + J 130.7 ohms 130.7/57.92 = 2.26 ratio in reactance for a diameter ratio change of 30:1. 454.7/289.6 = 1.57 resistance ratio for the 30:1 change If I adjust the tap point to a good match (at 14 feet above ground) I have: 3 inch diameter gamma conductor 32.68 + J 65.45 ohms 0.1 inch gamma diameter 52.04 + J 111 ohms 1.6 ratio in resistance and 1.7 in reactance for a 30:1 change in rod diameter. The primary benefit in a larger diameter gamma rod is lower Q and lower voltage across the tuning capacitor. If I shorten the element, I can gamma match without a capacitor. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We started with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell sort of stumbled on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime sort of stumbling on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Palomar R-X Noise Bridge
I just wanted to thank everyone who answered my question about coax impedance and how it would affect 1/4 wave stub length found and cut using a noise bridge. It won't. I though that was the way it worked, but I was not sure. I reasoned this group would have the answer. It did!! Another thing I love about this group is the way one simple question will be expanded on and applied to other similar subject. Always an education. 73 es DX Pat H. Armstrong KF5YZ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
- Original Message - From: Tom W8JI w...@w8ji.com To: 'TopBand' topband@contesting.com Sent: Saturday, February 15, 2014 12:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge Dielectric losses become evident at 2M with 1500W and at 432 400W of steady carrier will heat up even the best N connectors and RG-213. For that reason many are switching to the 7/16 DIN. That has nothing at all to do with dielectric losses. N connectors have a tiny BNC size center pin. RG-213 have a woven braid and stranded center conductor making the small center conductor diameter heating and shield heating even worse. Jim is correct. Conductor losses significantly dominate dielectric losses at UHF and lower to the point where dielectric loss is meaningless. There are exceptions, of course, but not with normal parts. I didnt say that resistive losses dont dominate but dielectric losses do contribute. A N connector center pin is larger than the coax that goes into it so its loss is not an extra contributor. The mating point of M and F continues that size and with the dielectric do an excellent job of maintaining 50 Ohms well into the microwavesat low signal levels. OTOH an Amphenol or similar quality UHF connector pair will go up in smoke as I found out when first testing my HB 2M amp at 1800W into the Bird load. I used RG-213 only as a size example; others that are in the same genre including 9913 and LMR 400 contribute their own heat as those migrating from SSB to digital modes for EME and earthly propagation have been finding out. Im sure that those running tubes with handles even on 160 have had to migrate away from the UHF set. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Walt surely did know his stuff and he published some great material!! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 15, 2014 4:31 PM To: Top Band Contesting Subject: Re: Topband: Palomar R-X Noise Bridge Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We started with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell sort of stumbled on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime sort of stumbling on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Palomar R-X Noise Bridge
Absolutely and I had the pleasure of meeting him and hear him speak. Unfortunately his very public arguments with Warren Bruene in QEX and elsewhere over the Conjugate Match and then showing up on various forums to publicly push his last book as part of his legacy (which contains his final words on the subject with no further discussion) while the battle was still in progress was a bit dissapointing. Several tried to engage him in a discussion but he didnt want to be challenged and the subject was pulled out of respect for all the good he has done over his long career. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Tom W8JI' w...@w8ji.com; 'Top Band Contesting' topband@contesting.com Sent: Saturday, February 15, 2014 4:35 PM Subject: Re: Topband: Palomar R-X Noise Bridge Walt surely did know his stuff and he published some great material!! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 15, 2014 4:31 PM To: Top Band Contesting Subject: Re: Topband: Palomar R-X Noise Bridge Maxwell sort of stumbled on it in later years with those tiny beads that seriously overheated with most amps. We started with the type that fit over RG-213 and went from there to custom made, the big donuts, and sheet products from pioneers such as Arnold. Walt Maxwell was not only a real nice guy, he knew his stuff. Walt was a senior antenna design engineer for RCA, including satellite antennas. It is outrageous to say Walt Maxwell sort of stumbled on something so simple, and that heating of beads relates to amplifiers. The heating is much more an issue of abnormal common mode impedances, rather than power levels. Walt's article, along with articles by Lewallen, accelerated use of common mode chokes and current baluns. They got us away from those silly voltage baluns people were using. People who don't understand how things work are the people who spend a lifetime sort of stumbling on things. Why, I remember when Walt patiently taught me how conductor losses dominated transmission line loss, and why that was important! :-) 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Contest in progress - few signals
There's a contest in progress --the ARRL Int. DX CW-- but you wouldn't know it from listening on 160. Where is everyone? The only two stations on 160 calling CQ TEST are K3LR and W3LPL. 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
Band has been poor here in NM. Last night didn't hear Europe at all, and only about 10 SA and Carrib. Stations. This morning, opening into Asia was marginal, with only a handful of weak JAs. Even Kim HL5IVL, who usually blasts through here, was barely out if the noise. 73, Jim W8ZR Sent from my iPhone On Feb 15, 2014, at 5:17 PM, Mike Waters mikew...@gmail.com wrote: There's a contest in progress --the ARRL Int. DX CW-- but you wouldn't know it from listening on 160. Where is everyone? The only two stations on 160 calling CQ TEST are K3LR and W3LPL. 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
I didn't notice that the K index jumped to 5 until after I posted this. That doesn't help. But the 3 or 4 stations that I hear calling CQ are quite strong (S9+) in SW Missouri. W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. 73, MIke www.w0btu.com On Sat, Feb 15, 2014 at 7:09 PM, MU 4CX250B 4cx2...@miamioh.edu wrote: Band has been poor here in NM. Last night didn't hear Europe at all, and only about 10 SA and Carrib. Stations. This morning, opening into Asia was marginal, with only a handful of weak JAs. Even Kim HL5IVL, who usually blasts through here, was barely out if the noise. 73, Jim W8ZR Sent from my iPhone On Feb 15, 2014, at 5:17 PM, Mike Waters mikew...@gmail.com wrote: There's a contest in progress --the ARRL Int. DX CW-- but you wouldn't know it from listening on 160. Where is everyone? The only two stations on 160 calling CQ TEST are K3LR and W3LPL. 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Update from AG6X shunt feed project
All I decided to take a chance at tapping the tower at 67' and apply some series capacitance to see how the structure would work there before tapping it at the 90' level. Here is what I found: The gamma arm spacing is at 33 and with 140pf in series I see 42+j0 ohms at the feedpoint. Inside the shack at the end of the LMR 400 I see basically FLAT SWR from 1800 to 1850 and 1.5:1 at 1865...with the cap fixed at 140pf. All of that with my skimpy (single 14AWG) gamma wire. Tomorrow I plan on dropping the tower again to add the additional 2 or 3 wires to create the gamma wire cage. My current PVC standoffs have been modified to accept three gamma wires spaced approx. 10 apart (though I'm only using one now as I said before). I'm assuming this MAY provide me with a couple more ohms getting me closer to the magical 50 but bandwidth is what I'm truly after. If I still need a few more ohms I may extend the gamma and standoff arms out another 6 or so...which would be the MAX reach without installing new arm and standoffs. So...with these low capacitance requirements (140pf now and possibly less with the multiple gamma wires) will I still need to scrounge my vacuum variable out of storage or will my 4500V Cardwell cap get the job done at 1500W? Thanks to all who offered their advice and look for an update from me after the gamma cage is assembled and additional radials are installed Carl AG6X _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
I didn't notice that the K index jumped to 5 until after I posted this. That doesn't help. But the 3 or 4 stations that I hear calling CQ are quite strong (S9+) in SW Missouri. W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. He would hear you better if you were DX, and he needed to work you. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
- Original Message - From: Tom W8JI w...@w8ji.com To: Mike Waters mikew...@gmail.com Cc: topband topband@contesting.com Sent: Saturday, February 15, 2014 9:58 PM Subject: Re: Topband: Contest in progress - few signals W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. From USA Canada- He earns contest points for DX contacts only He would hear you better if you were DX, and he needed to work you. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
I kind of thought that might have been the case. :-) Anyway, the band is much better now. I've been hearing Europe and SA. 73, Mike www.w0btu.com On Sat, Feb 15, 2014 at 8:58 PM, Tom W8JI w...@w8ji.com wrote: W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. He would hear you better if you were DX, and he needed to work you. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
Then maybe I misread the rules at http://www.hornucopia.com/contestcal/weeklycont.php#5126 . 73, Mike www.w0btu.com On Sat, Feb 15, 2014 at 9:20 PM, Bruce k...@myfairpoint.net wrote: W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. From USA Canada- He earns contest points for DX contacts only He would hear you better if you were DX, and he needed to work you. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
Looks pretty plain, you count for nothing zero nada QRM to another USA W/VE: Each DXCC country once per band Non-W/VE: Each state, District of Columbia, VE province/territory once per band Then maybe I misread the rules at http://www.hornucopia.com/contestcal/weeklycont.php#5126 . 73, Mike www.w0btu.com On Sat, Feb 15, 2014 at 9:20 PM, Bruce k...@myfairpoint.net wrote: W3LPL is S9+, but he had a lot of trouble hearing my 1500 watts. Odd. From USA Canada- He earns contest points for DX contacts only He would hear you better if you were DX, and he needed to work you. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
Still poor in central KL7. Maybe later. Aurora’s heating up, so maybe never: http://www.swpc.noaa.gov/pmap/index.html GL es 73, Gary NL7Y _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Contest in progress - few signals
I'll take your word (and Tom's) for it. But that's not how I interpreted what Bruce states there. QSO Points: 3 points per QSO evidently should say: QSO Points: 3 points per DX QSO. Thanks. 73, Mike www.w0btu.com On Sat, Feb 15, 2014 at 10:13 PM, Merv Schweigert k...@flex.com wrote: Looks pretty plain, you count for nothing zero nada QRM to another USA W/VE: Each DXCC country once per band Non-W/VE: Each state, District of Columbia, VE province/territory once per band Then maybe I misread the rules at http://www.hornucopia.com/contestcal/weeklycont.php#5126 . _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Fwd: Contest in progress - few signals
Hi ! Bad condition ... only W1UE, WE3C = QSO W3LPL, K3LR copy, calling, but no QSO Aurora ! http://www.tesis.lebedev.ru/magnetic_storms.html See on HF GL in ARRL DX Contest 73! de UR5IFB Суббота, 15 февраля 2014, 19:29 -09:00 от Gary and Kathleen Pearse pea...@gci.net: Still poor in central KL7. Maybe later. Aurora’s heating up, so maybe never: http://www.swpc.noaa.gov/pmap/index.html GL es 73, Gary NL7Y _ Topband Reflector Archives - http://www.contesting.com/_topband С уважением, ur5...@mail.ru _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Fw: Contest in progress - few signals
- Original Message - From: Mike Waters mikew...@gmail.com To: Merv Schweigert k...@flex.com; topband topband@contesting.com Sent: Saturday, February 15, 2014 11:39 PM Subject: Re: Topband: Contest in progress - few signals I'll take your word (and Tom's) for it. But that's not how I interpreted what Bruce states there. This is what I said wasFrom USA Canada- He earns contest points for DX contacts only73 Bruce An ARRL contest: http://www.arrl.org/arrl-dx QSO Points: 3 points per QSO evidently should say: QSO Points: 3 points per DX QSO. Thanks. 73, Mike www.w0btu.com On Sat, Feb 15, 2014 at 10:13 PM, Merv Schweigert k...@flex.com wrote: Looks pretty plain, you count for nothing zero nada QRM to another USA W/VE: Each DXCC country once per band Non-W/VE: Each state, District of Columbia, VE province/territory once per band Then maybe I misread the rules at http://www.hornucopia.com/contestcal/weeklycont.php#5126 . _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: TO7CC
Operating as W1AW/9 I worked them at 0135Z Saturday night on 80M. They had a pretty good signal. They were operating high in the band, 3555. On 2/14/2014 11:21 AM, Jim Brown wrote: Has anyone heard or worked these guys on 80 or 160? 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4335 / Virus Database: 3705/7094 - Release Date: 02/14/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
