Re: Topband: Shunt feeding the Skyneedle - new developments
I'm sure it will play well in terms of keeping your transmitter happy but the relatively large bandwidth you are measuring is indicative of substantial loss in the system somewhere. This would be a large bandwidth even if you did not have the bandwidth narrowing effects of a shunt feed. Hi guys, the 3 wires is actually a transmission line and the antenna is well known as Folded Unipole with 200 ohms impedance. My antenna is a Folded Unipole as well and has the same broadband SWR measurement's. The loss is the same for any tuning circuit it has nothing to do with the bandwidth. The ground plane does, and in this case it is the same, right? 73's JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Good morning, JC Well, in its present configuration, Carl's antenna is not really a folded monopole, although it did start our as one when he had his gamma match connected at full height of 90'. At present he has his gamma attached at 67' - about 2/3 of the way up the tower. But that's sort of a nit-pick - otherwise, I do agree that the gamma match (with its 3-wire cage, is a shorted transmission line section. Since it's less than 1/4 wavelength it will have inductive reactance that needs to be canceled with the series tuning capacitor. Carl should have a good topband transmit antenna! As he builds out his radial field, the efficiency will hopefully improve some more. I hope he had fun with it last night, but 160 conditions of late have been rather poor - apparently because of the sun's coronal mass ejection a few days ago. Have a good day!\ 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of JC N4IS Sent: Sunday, February 23, 2014 7:20 AM To: 'Richard (Rick) Karlquist'; 'Carl Braun'; 'Carl'; '160' Cc: w...@att.net; ad...@arrl.net Subject: Re: Topband: Shunt feeding the Skyneedle - new developments I'm sure it will play well in terms of keeping your transmitter happy but the relatively large bandwidth you are measuring is indicative of substantial loss in the system somewhere. This would be a large bandwidth even if you did not have the bandwidth narrowing effects of a shunt feed. Hi guys, the 3 wires is actually a transmission line and the antenna is well known as Folded Unipole with 200 ohms impedance. My antenna is a Folded Unipole as well and has the same broadband SWR measurement's. The loss is the same for any tuning circuit it has nothing to do with the bandwidth. The ground plane does, and in this case it is the same, right? 73's JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Tom I assume the system has reactance since the MFJ is reading the X and I'm seeing the resulting SWR on the analyzer AND at the rig. The swr at my given freq as tuned with the variable cap is 1.3:1 or less...outside the enclosure the system had 1.0:1 swr readings and X=O over what appeared to be a broader bandwidth...even with 42 ohms at the feed point. I'm having fun in the contest and the antenna seems to be transmitting well and the amp hasn't blown up yet. I have a very short run of RG58 from the panel to my switching network so I'm keeping the amplifier below 500W. I'm definitely ready to get the RX loop up as listening on the needle is rough. Thanks Tom Carl AG6X -Original Message- From: Tom W8JI [mailto:w...@w8ji.com] Sent: Saturday, February 22, 2014 12:17 AM To: Carl Braun Cc: 160 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The j11 ohms is the best I can get period. I was able to get j0 when the cap was outside of the steel enclosure with a better bandwidth. Maybe I should throw my $400 enclosure and find a fibergla$$ enclosure. But as others have indicated I should probably just live with it. 1.) How do you know the system really has some reactance? 2.) What is the SWR, that is more accurate. 3.) The SWR is meaningless anyway for control settings when it is below maybe 1.3, and is typically meaningless for system losses when below 4.0:1 for short cables on 160 meters. A 40 j10 load (if it is that) is around 1.3:1, so it falls in the meaningless category Do you think a smaller (physically) vacuum cap would have less interaction with the steel enclosure. The one I have is only 3 round and 6 long. The air variable I'm using is 13 long and 7 round at mesh RF behavior with chassis and cabinets and wiring can be complicated. Some people who work around it all their life never actually get a feel for how simple systems work, let alone things that might get colex like high impedance lines and physically large components inside close spaced boxes. The interaction depends on the circuit impedance and the impedance of any components and wiring at various points in the system inside the box. You'll probably never get a meaningful answer because the problem is small, an answer requires knowing the actual impedances of everything, and at a minimum a feel for how the box and wiring *you* have interacts with the impedances. The important thing at this point is how the equipment in the shack behaves with what you have, because any actual losses are meaningless. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Charlie Thanks for the tip. I may play with a bit of inductance just to see how the system reacts. Not sure if I can post a pic here but I'm including a shot of the panel and the cap...hope you all can see it. The static bleed choke has been removed and I'm awaiting PL 259 connectors from my friends at RF parts. My crazy dog gets pretty loopy when we play with the Frisbee so I'm considering a trial cut in the asphalt to see how easy or ugly the process is. I hear the secret is all in the blade that's used. You Tube has some videos showing the procedure for cutting asphalt...we'll see. Thanks again Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 8:18 PM To: Carl Braun; 'ZR'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Hi, Carl Well, I think that what you are doing with your radials should be OK. I guess I'd rather get them under the asphalt if I could where they wouldn't get torn up or b a trip hazard. BTW I I was playing with your match on the Smith Chart and if you'll add about 1 uHy inductance in series with the connector (SO-239?) where you feedline leaves the enclosure, that will take you to 45 +j0, but I'd be concerned about incurring more losses in the inductor than any tiny mismatch loss from the -j11 term. I probably wouldn't do it. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 10:56 PM To: Charlie Cunningham; 'ZR'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments I'm working on the radial field weekly. Here is a theoretical question that results from my particular QTH. The Skyneedle is situated near a secondary blacktop driveway that is in the back of my property. I have to run radials over the blacktop to the rest of the property and, in order to keep things kind of neat, I'm using multi-conductor rotor cable as radials that travel over the blacktop. I have both 6 conductor and 3 conductor control cable that I'm using. I strip back the jacket at the radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper pipe I'm using as a radial ring around the base of the 'Needle'. Then the radial wires converge back into the cable jacket then travel across the 10' blacktop driveway and then they are removed from the cable jacket where they fan out into the dirt and are buried. Most of these radial wires are 60' to 100' once they leave the jacket. Any problem with what I'm doing here? I understand that it would be better if they fanned out directly from the base but I can have 50+ wires traveling over the blacktop. I was even considering getting an asphalt blade and cutting some channels into the blacktop...burying the jacketed cable into the asphalt and then sealing then in so I'm not running over them or tripping over them when playing Frisbee with the hound. My Guatemalan yard worker has been burying radial wires for the last month and thinks that I'm LOCO but he likes getting paid at the end of the day. As we speak I have a total of 34 radials with the shortest being 30' with the longest at 100'. Most of them are 60-70'. Four of them are tied into my 40m phased array radial field comprised of 90-100 radials under each antenna ranging from 40' to 80'. I can change the height of these verticals from 33' for 40m to 66' for 80m. 1/2 wl spacing on 40 and 1/4 wl spacing on 80. Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 7:36 PM To: 'ZR'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle
Re: Topband: Shunt feeding the Skyneedle - new developments
Hi, Carl Well, paying with your load on a Smith Chart, tuning out the -j11 only improved the VSWR from 1.3:1 to 1.1 - not really worth doing! Also, you would need a fairly large inductor to obtain 1 uHy of inductance with low loss, and I expect that you would incur more loss in the inductor (that would subtract directly from your transmitted power) than you would gain in improved mismatch loss by improving the VSWR from 1.3 t 1.1!! Keep in mind also that the inductor would also have stray capacitance to the enclosure walls that will lower its Q ! I wouldn't do it! 1.3:1 is great!! Enjoy!! You will help your overall performance much more by building a terminated receiving loop - a KAZ, flag or pennant configuration to help your HEARING!! MY KAZ loop did wonders for me!! GL and have fun! 73, Charlie, K4OTV -Original Message- From: Carl Braun [mailto:carl.br...@lairdtech.com] Sent: Saturday, February 22, 2014 7:23 AM To: Charlie Cunningham; 'ZR'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Charlie Thanks for the tip. I may play with a bit of inductance just to see how the system reacts. Not sure if I can post a pic here but I'm including a shot of the panel and the cap...hope you all can see it. The static bleed choke has been removed and I'm awaiting PL 259 connectors from my friends at RF parts. My crazy dog gets pretty loopy when we play with the Frisbee so I'm considering a trial cut in the asphalt to see how easy or ugly the process is. I hear the secret is all in the blade that's used. You Tube has some videos showing the procedure for cutting asphalt...we'll see. Thanks again Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 8:18 PM To: Carl Braun; 'ZR'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Hi, Carl Well, I think that what you are doing with your radials should be OK. I guess I'd rather get them under the asphalt if I could where they wouldn't get torn up or b a trip hazard. BTW I I was playing with your match on the Smith Chart and if you'll add about 1 uHy inductance in series with the connector (SO-239?) where you feedline leaves the enclosure, that will take you to 45 +j0, but I'd be concerned about incurring more losses in the inductor than any tiny mismatch loss from the -j11 term. I probably wouldn't do it. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 10:56 PM To: Charlie Cunningham; 'ZR'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments I'm working on the radial field weekly. Here is a theoretical question that results from my particular QTH. The Skyneedle is situated near a secondary blacktop driveway that is in the back of my property. I have to run radials over the blacktop to the rest of the property and, in order to keep things kind of neat, I'm using multi-conductor rotor cable as radials that travel over the blacktop. I have both 6 conductor and 3 conductor control cable that I'm using. I strip back the jacket at the radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper pipe I'm using as a radial ring around the base of the 'Needle'. Then the radial wires converge back into the cable jacket then travel across the 10' blacktop driveway and then they are removed from the cable jacket where they fan out into the dirt and are buried. Most of these radial wires are 60' to 100' once they leave the jacket. Any problem with what I'm doing here? I understand that it would be better if they fanned out directly from the base but I can have 50+ wires traveling over the blacktop. I was even considering getting an asphalt blade and cutting some channels into the blacktop...burying the jacketed cable into the asphalt and then sealing then in so I'm not running over them or tripping over them when playing Frisbee with the hound. My Guatemalan yard worker has been burying radial wires for the last month and thinks that I'm LOCO but he likes getting paid at the end of the day. As we speak I have a total of 34 radials with the shortest being 30' with the longest at 100'. Most of them are 60-70'. Four of them are tied into my 40m phased array radial field comprised of 90-100 radials under each antenna ranging from 40' to 80'. I can change the height of these verticals from 33' for 40m to 66' for 80m. 1/2 wl spacing on 40 and 1/4 wl spacing on 80. Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 7:36 PM To: 'ZR'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz
Re: Topband: Shunt feeding the Skyneedle - new developments
Thanks for the tip. I may play with a bit of inductance just to see how the system reacts. This is way more problematic than it needs to be. First, no one even knows if the reactance is real or a false reading caused by a bit error from calibration or noise. Second, no one knows the sign of the reactance if it is there. It might be already be inductive. Third, if the capacitor is not maxed out or at minimum and still has range left, which yours does, the capacitor will adjust out any reactance without adding anything else. There are certain bridge voltages that with even one or two bits error, which is 2/256 bits or less than 1% error in voltages, where 10 ohms might be calculated. The algoryth tries to take that error out by watching SWR near bridge balance instead of bridge arm voltages, but I have no idea how the unit is calibrated or if the antenna system has noise causing a bit error. All of this is pretty much meaningless. Even if it is a 1.3 :1 SWR, it is not going to be a problem. Also, if the real part is near 40 ohms and you have a high Q antenna system and losses, you might find lowest SWR is not X=0 because of interactions between resistance and reactance as things are tuned. I would not even guess at a cure for something with a bunch of unknowns that might not even be a problem. I think this is a bigger worry and more complex than it should be. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas
Re: Topband: Shunt feeding the Skyneedle - new developments
I completely agree with Tom. Carl! I'd leave it alone(for the reasons that I stated previously)! I expect that you would lose more than you would gain by adding an inductor!! If it ain't broke don't fix it!! You might want to put some effort into a good terminated receiving loop! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 22, 2014 9:09 AM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks for the tip. I may play with a bit of inductance just to see how the system reacts. This is way more problematic than it needs to be. First, no one even knows if the reactance is real or a false reading caused by a bit error from calibration or noise. Second, no one knows the sign of the reactance if it is there. It might be already be inductive. Third, if the capacitor is not maxed out or at minimum and still has range left, which yours does, the capacitor will adjust out any reactance without adding anything else. There are certain bridge voltages that with even one or two bits error, which is 2/256 bits or less than 1% error in voltages, where 10 ohms might be calculated. The algoryth tries to take that error out by watching SWR near bridge balance instead of bridge arm voltages, but I have no idea how the unit is calibrated or if the antenna system has noise causing a bit error. All of this is pretty much meaningless. Even if it is a 1.3 :1 SWR, it is not going to be a problem. Also, if the real part is near 40 ohms and you have a high Q antenna system and losses, you might find lowest SWR is not X=0 because of interactions between resistance and reactance as things are tuned. I would not even guess at a cure for something with a bunch of unknowns that might not even be a problem. I think this is a bigger worry and more complex than it should be. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV
Re: Topband: Shunt feeding the Skyneedle - new developments
That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:23 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz, even at 2.0:1 or 3.0 :1, if he can match it at the transmitter end of the line, it really doesn't matter! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:46 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:23 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl
Re: Topband: Shunt feeding the Skyneedle - new developments
Charlie youre continually missing the point; ignore cable loss period. The only issue is what impedance does the amp see from lets say 1800 to 1900 KHz? AND can the amp load into it without a problem at full power? This is a system issue, not just what is measured at the antenna and needs to be addressed that way. Put all that info into your program and post the results. Saying that a 1.3 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute the VSWR at the amp with whatever length of coax is actually used over the lower 100 KHz with a range of at resonance VSWR's. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:57 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz, even at 2.0:1 or 3.0 :1, if he can match it at the transmitter end of the line, it really doesn't matter! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:46 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:23 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat 1:1 at the transmitter end of his cable. I believe he is done!! The antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce his radial field and increase his ground losses to improve his 2:1 BW - but I believe that to be self-defeating!! I'm not missing your point - I just don't see what you'd change to improve on a flat line! Carl is well past the point of diminishing returns! The math doesn't lie! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 10:41 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Charlie youre continually missing the point; ignore cable loss period. The only issue is what impedance does the amp see from lets say 1800 to 1900 KHz? AND can the amp load into it without a problem at full power? This is a system issue, not just what is measured at the antenna and needs to be addressed that way. Put all that info into your program and post the results. Saying that a 1.3 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute the VSWR at the amp with whatever length of coax is actually used over the lower 100 KHz with a range of at resonance VSWR's. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:57 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz, even at 2.0:1 or 3.0 :1, if he can match it at the transmitter end of the line, it really doesn't matter! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:46 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:23 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February 21, 2014 10:35 PM Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd
Re: Topband: Shunt feeding the Skyneedle - new developments
It may not be obvious but often you can get better bandwidth by NOT tuning for 1:1 at the desired frequency! Those familiar with the Smith chart probably already know this. A narrow band antenna will produce a curve between a U and a V on the Smith chart. If you tune for a 1:1 SWR, you bring the nose of the curve to the center of the chart. This often leaves the tails outside the desired SWR circle. If you continue until the nose goes to the opposite side of the SWR circle, it brings more of the tails into the circle. The resulting SWR curve is a W shape. It won't be 1:1 at any frequency but more of the curve will lie within the chosen SWR circle. 73, Roger On 2/22/2014 11:03 AM, Charlie Cunningham wrote: Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat 1:1 at the transmitter end of his cable. I believe he is done!! The antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce his radial field and increase his ground losses to improve his 2:1 BW - but I believe that to be self-defeating!! I'm not missing your point - I just don't see what you'd change to improve on a flat line! Carl is well past the point of diminishing returns! The math doesn't lie! Charlie, K4OTV _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
I suppose I missed that part while doing things around here but this is the only pertinent info I can find from him. Nowhere does it say he has a 1:1 anywhere with the cap in the cabinet. Granted some of the posts are very confusing as to where things are being measured. -- The j11 ohms is the best I can get period. I was able to get j0 when the cap was outside of the steel enclosure with a better bandwidth. Maybe I should throw my $400 enclosure and find a fibergla$$ enclosure. But as others have indicated I should probably just live with it. The swr at my given freq as tuned with the variable cap is 1.3:1 or less...outside the enclosure the system had 1.0:1 swr readings and X=O over what appeared to be a broader bandwidth...even with 42 ohms at the feed point. -- So maybe you can explain where the 1.0 at the transmitter end with the cap in the box came from? Additionally the VSWR may/will change with added radials and ground moisture conditions. Im going out for several hours so no rush on the answers. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 11:03 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat 1:1 at the transmitter end of his cable. I believe he is done!! The antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce his radial field and increase his ground losses to improve his 2:1 BW - but I believe that to be self-defeating!! I'm not missing your point - I just don't see what you'd change to improve on a flat line! Carl is well past the point of diminishing returns! The math doesn't lie! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 10:41 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Charlie youre continually missing the point; ignore cable loss period. The only issue is what impedance does the amp see from lets say 1800 to 1900 KHz? AND can the amp load into it without a problem at full power? This is a system issue, not just what is measured at the antenna and needs to be addressed that way. Put all that info into your program and post the results. Saying that a 1.3 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute the VSWR at the amp with whatever length of coax is actually used over the lower 100 KHz with a range of at resonance VSWR's. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:57 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz, even at 2.0:1 or 3.0 :1, if he can match it at the transmitter end of the line, it really doesn't matter! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:46 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:23 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments I don't expect that ANY of those are valid concerns at 1.3:1 VSWR!! -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:14 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Im not concerned by what is measured at the matching unit or a miniscule cable loss; just what is transformed back to the amp and its ability to load at full power without arcing, running out of or having too much fixed padder C during QSY's. Contests do not stay just in the narrow CW 50 KHz window and not having to use an external tuner is a big plus. Ive always modified my amps to work with my antennas on 160 and 80/75. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'ZR' z...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Friday, February
Re: Topband: Shunt feeding the Skyneedle - new developments
Wel, I agree with all of that, Roger. I plotted Carl's 45-j11 load on a 50 ohm Smith Chart, and it's right near the origin of the chart on a 1.3:1 VSWR circle. I'd need some more data points at some other frequencies to plot to get a better picture of what's going on, But his VSWR is so low that the losses in 70' of LMR-400 on 160 are completely negligible! As long as he can match it at the transmitter end - no problem! And at one point, he was measuring dead-flat 1:1at the tranmitterend of the cable. His Henry amp should handle that just fine without a tuner! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Roger D Johnson Sent: Saturday, February 22, 2014 11:16 AM To: '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments It may not be obvious but often you can get better bandwidth by NOT tuning for 1:1 at the desired frequency! Those familiar with the Smith chart probably already know this. A narrow band antenna will produce a curve between a U and a V on the Smith chart. If you tune for a 1:1 SWR, you bring the nose of the curve to the center of the chart. This often leaves the tails outside the desired SWR circle. If you continue until the nose goes to the opposite side of the SWR circle, it brings more of the tails into the circle. The resulting SWR curve is a W shape. It won't be 1:1 at any frequency but more of the curve will lie within the chosen SWR circle. 73, Roger On 2/22/2014 11:03 AM, Charlie Cunningham wrote: Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat 1:1 at the transmitter end of his cable. I believe he is done!! The antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce his radial field and increase his ground losses to improve his 2:1 BW - but I believe that to be self-defeating!! I'm not missing your point - I just don't see what you'd change to improve on a flat line! Carl is well past the point of diminishing returns! The math doesn't lie! Charlie, K4OTV _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
The measurements are being taken, and have been taken, at the same point since the beginning of the antenna experiment. The ONLY difference is that the variable cap is now mounted inside the steel panel as described in my previous posts, instead of outside the panel, as described in previous posts. Same length of wire each scenario. I believe Tom W8JI called it when he stated that a change was likely when the cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic jug. The Henry amp seems to be OK with a little reactance so I'm going to concentrate on my gamma cage and radial system while waiting for RF Parts to deliver some necessary connectors. Once I get the PL259s installed I can replace my temp RG 58 jumper with the good stuff and then hit it with the Henry. Ive kept the power below 500w during the contest so as not to stress the small coaxial cable. 73 Carl Sent from my iPhone On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote: I suppose I missed that part while doing things around here but this is the only pertinent info I can find from him. Nowhere does it say he has a 1:1 anywhere with the cap in the cabinet. Granted some of the posts are very confusing as to where things are being measured. -- The j11 ohms is the best I can get period. I was able to get j0 when the cap was outside of the steel enclosure with a better bandwidth. Maybe I should throw my $400 enclosure and find a fibergla$$ enclosure. But as others have indicated I should probably just live with it. The swr at my given freq as tuned with the variable cap is 1.3:1 or less...outside the enclosure the system had 1.0:1 swr readings and X=O over what appeared to be a broader bandwidth...even with 42 ohms at the feed point. -- So maybe you can explain where the 1.0 at the transmitter end with the cap in the box came from? Additionally the VSWR may/will change with added radials and ground moisture conditions. Im going out for several hours so no rush on the answers. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 11:03 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, I agree with all that, Carl. But Carl Braun, was reading dead-flat 1:1 at the transmitter end of his cable. I believe he is done!! The antenna Q is what it is! As for improving his 2:1 VSWR bandwidth he could reduce his radial field and increase his ground losses to improve his 2:1 BW - but I believe that to be self-defeating!! I'm not missing your point - I just don't see what you'd change to improve on a flat line! Carl is well past the point of diminishing returns! The math doesn't lie! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 10:41 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Charlie youre continually missing the point; ignore cable loss period. The only issue is what impedance does the amp see from lets say 1800 to 1900 KHz? AND can the amp load into it without a problem at full power? This is a system issue, not just what is measured at the antenna and needs to be addressed that way. Put all that info into your program and post the results. Saying that a 1.3 VSWR at reasonance at the antenna is sufficient is too simplistic. Compute the VSWR at the amp with whatever length of coax is actually used over the lower 100 KHz with a range of at resonance VSWR's. Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband@contesting.com Sent: Saturday, February 22, 2014 9:57 AM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl the looses in 70' or even 200' of LMR-400 are so low at 1.8 MHz, even at 2.0:1 or 3.0 :1, if he can match it at the transmitter end of the line, it really doesn't matter! Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 9:46 AM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That 1.3 is only at ONE frequency Charlie, he is not crystal controlled. What is the 2:1 bandwidth at the amp? Carl KM1H - Original Message - From: Charlie Cunningham charlie-cunning...@nc.rr.com To: 'Carl' k...@jeremy.mv.com; 'Carl Braun' carl.br...@lairdtech.com; '160' topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Carl and Topbanders Here are the latest details and I will try and be as thorough as possible. Good news! I built my gamma cage and the antenna now performs MUCH better. Here's where I stand: 90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire gamma cage with 10 separation between wires. My tower is grounded at the base via three 1 copper strap 1/8th inch thick and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The radial ring is also bonded to three 8' ground rods via 1 copper strap. Currently I have approx 30 ground radials screwed to the radial ring with copper clad stainless screws and then painted with copper paste. Some of the radials are formed from heavy control cable (similar to rotor cable) that are fanned out at the radial ring...converge into the Cable jacket, cross the 10' blacktop driveway and then emerge from the jacket and fan out across the property. The radials vary from 30' long to 100' long with three of them tying directly into the radial field of my 40m phased array. The three-wire gamma cage is made of 14ga stranded wire and converges into a cone with a single brass bolt holding all three ring lugs together 1.5' off of the ground at the base. An additional 14ga wire is also connected to the brass bolt and bolts to a porcelain feed through insulator that brings the feed into the metallic (STEEL) panel. A 14ga wire then bolts to the other end of the feed thru insulator and taps onto the input of the Cardwell air variable capacitor. The output of the capacitor connects to a SO 239 connector that is mounted to a 2 copper strap that travels down the enclosure where two brass bolts bolt the strap to the bottom of the panel. Under the panel, where the brass bolts emerge from the panel, two 2 copper straps connect to the brass bolts and then travel to the copper radial ring where they are terminated. Before the gamma cage I used a single 14ga wire dropped down from the gamma arm where it connected to the variable cap that was mounted outside my steel enclosure and sat on a plastic 5 gal pail. The gamma wire connected to the variable cap and then it was wired to the same standoff insulator I mentioned above and into an empty steel panel where I had the same SO 239 connector mounted to the copper strap and then to my grounding system. This config netted me 41 + j0 ohms. I was pretty satisfied with this scenario so I mounted my variable cap on a 3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the steel enclosure. When I did this I saw my analyzer jump to 45 -j11 ohms. No matter how much tweaking was done the lowest X on the analyzer was 11. Figuring I could live with that after making 24 contacts this morning I decided to move ahead with my gamma cage. When I completed the cage per the info above I left my analyzer set on the previous frequency setting of 1825 and saw the resistance jump and the X go out of site. Adjusting my variable cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading. Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz. I'm eager to get back on the air tonight and tomorrow morning to see how it plays 73 Carl AG6X -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 22, 2014 1:22 PM To: Carl Braun Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The measurements are being taken, and have been taken, at the same point since the beginning of the antenna experiment. ** How about refreshing my merory about those details Carl? Frequency also. I wasnt involved in the early parts and deleted them already. The ONLY difference is that the variable cap is now mounted inside the steel panel as described in my previous posts, instead of outside the panel, as described in previous posts. Same length of wire each scenario. I believe Tom W8JI called it when he stated that a change was likely when the cap is enclosed in a metallic enclosure vs sitting on a 5 gal plastic jug. ** No discussion needed there, thats been known for 100 years. It would also help to be more specific when presenting details, what does metallic really mean? The Henry amp seems to be OK with a little reactance so I'm going to concentrate on my gamma cage and radial system while waiting for RF Parts to deliver some necessary connectors. Once I get the PL259s installed I can replace my temp RG 58 jumper with the good stuff and then hit it with the Henry. I've kept the power below 500w during the contest so as not to stress the small coaxial cable. ** Good move. Carl KM1H 73 Carl Sent from my iPhone On Feb 22, 2014, at 8:42 AM, Carl k...@jeremy.mv.com wrote: I suppose I missed that part while doing things around here but this is the only
Re: Topband: Shunt feeding the Skyneedle - new developments
On 2/22/2014 4:15 PM, Carl Braun wrote: Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz. I'm eager to get back on the air tonight and tomorrow morning to see how it plays I'm sure it will play well in terms of keeping your transmitter happy but the relatively large bandwidth you are measuring is indicative of substantial loss in the system somewhere. This would be a large bandwidth even if you did not have the bandwidth narrowing effects of a shunt feed. Does your 1000D SWR meter agree with your Bird meter? I am somewhat skeptical of the SWR meter on my 1000D. I suspect it reads on the low side. Either that or my Alpha 9500 reads on the high side. 73 Carl AG6X Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
I was pretty satisfied with this scenario so I mounted my variable cap on a 3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the steel enclosure. When I did this I saw my analyzer jump to 45 -j11 ohms. No matter how much tweaking was done the lowest X on the analyzer was 11. Figuring I could live with that after making 24 contacts this morning I decided to move ahead with my gamma cage. When I completed the cage per the info above I left my analyzer set on the previous frequency setting of 1825 and saw the resistance jump and the X go out of site. Adjusting my variable cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading. Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz. I would expect you to have that bandwidth. It does NOT indicate loss. Your shunt system now has an operating Q of around 4, because you now have 200 ohms of series C. With a thick radiator and a large yagi on top, and so much capacitance, you are exactly on target. While I don't fully trust the FT1000 meter, no matter what, never automatically assume modest bandwidth like you have indicates loss. It doesn't. There are a whole lot of things that go into bandwidth beside loss! 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Exactly! All true and Tom is right on point! You have removed a lot of series reactance with that gamma cage, Carl -as indicated by the required tuning C changing.from 160 pF ot over 400 pF. OF COURSE the Q was reduced as the series reactance was reduced and the real part stayed fairly constant. That does not imply increased or excessive loss! Regards Charlie -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Saturday, February 22, 2014 9:07 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments I was pretty satisfied with this scenario so I mounted my variable cap on a 3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the steel enclosure. When I did this I saw my analyzer jump to 45 -j11 ohms. No matter how much tweaking was done the lowest X on the analyzer was 11. Figuring I could live with that after making 24 contacts this morning I decided to move ahead with my gamma cage. When I completed the cage per the info above I left my analyzer set on the previous frequency setting of 1825 and saw the resistance jump and the X go out of site. Adjusting my variable cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading. Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz. I would expect you to have that bandwidth. It does NOT indicate loss. Your shunt system now has an operating Q of around 4, because you now have 200 ohms of series C. With a thick radiator and a large yagi on top, and so much capacitance, you are exactly on target. While I don't fully trust the FT1000 meter, no matter what, never automatically assume modest bandwidth like you have indicates loss. It doesn't. There are a whole lot of things that go into bandwidth beside loss! 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
That is the type of report I really like to hear Carl. All that work has paid off in spades. As you increase the number of radials the VSWR bandwidth might decrease along with the R which is normal as the ground resistance decreases. Since it appears to work so well you might just leave it alone for awhile, operate and get a feel of how your signal compares with others. With the top loading Id say the tower is close to being a 1/4 wave and the perfect world impedance about 35-36 Ohms with the remainder as ground resistance. That will result in very decent efficiency. That cage you connected this morning sure changed the numbers from the single wire I was responding to. OK on the steel panel. The usual rule of thumb there is to space coils and variables at least their width away. There were some amps and tuners on the market that would have radically different tuning, and more power out in the amplifier examples, with the cover removed. Take a bow, Im impressed!! Carl KM1H - Original Message - From: Carl Braun carl.br...@lairdtech.com To: Carl k...@jeremy.mv.com; '160' topband@contesting.com Cc: ad...@arrl.net; w...@att.net Sent: Saturday, February 22, 2014 7:15 PM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Carl and Topbanders Here are the latest details and I will try and be as thorough as possible. Good news! I built my gamma cage and the antenna now performs MUCH better. Here's where I stand: 90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire gamma cage with 10 separation between wires. My tower is grounded at the base via three 1 copper strap 1/8th inch thick and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The radial ring is also bonded to three 8' ground rods via 1 copper strap. Currently I have approx 30 ground radials screwed to the radial ring with copper clad stainless screws and then painted with copper paste. Some of the radials are formed from heavy control cable (similar to rotor cable) that are fanned out at the radial ring...converge into the Cable jacket, cross the 10' blacktop driveway and then emerge from the jacket and fan out across the property. The radials vary from 30' long to 100' long with three of them tying directly into the radial field of my 40m phased array. The three-wire gamma cage is made of 14ga stranded wire and converges into a cone with a single brass bolt holding all three ring lugs together 1.5' off of the ground at the base. An additional 14ga wire is also connected to the brass bolt and bolts to a porcelain feed through insulator that brings the feed into the metallic (STEEL) panel. A 14ga wire then bolts to the other end of the feed thru insulator and taps onto the input of the Cardwell air variable capacitor. The output of the capacitor connects to a SO 239 connector that is mounted to a 2 copper strap that travels down the enclosure where two brass bolts bolt the strap to the bottom of the panel. Under the panel, where the brass bolts emerge from the panel, two 2 copper straps connect to the brass bolts and then travel to the copper radial ring where they are terminated. Before the gamma cage I used a single 14ga wire dropped down from the gamma arm where it connected to the variable cap that was mounted outside my steel enclosure and sat on a plastic 5 gal pail. The gamma wire connected to the variable cap and then it was wired to the same standoff insulator I mentioned above and into an empty steel panel where I had the same SO 239 connector mounted to the copper strap and then to my grounding system. This config netted me 41 + j0 ohms. I was pretty satisfied with this scenario so I mounted my variable cap on a 3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the steel enclosure. When I did this I saw my analyzer jump to 45 -j11 ohms. No matter how much tweaking was done the lowest X on the analyzer was 11. Figuring I could live with that after making 24 contacts this morning I decided to move ahead with my gamma cage. When I completed the cage per the info above I left my analyzer set on the previous frequency setting of 1825 and saw the resistance jump and the X go out of site. Adjusting my variable cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading. Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0:1 from 1.810 to 1.860 and 1.5:1 at 1.895 MHz. I'm eager to get back on the air tonight and tomorrow morning to see how it plays 73 Carl AG6X -Original Message- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 22, 2014 1:22 PM To: Carl Braun Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The measurements are being taken, and have been taken, at the same point since the beginning of the antenna experiment
Re: Topband: Shunt feeding the Skyneedle - new developments
I'm impressed, too! I believe Carl has it whipped!! Should be a really good transmit antenna for Topband!!b Changing to that multi-wire gamma cage really eliminated a lot of series reactance and lowered the Q of the matching section and antenna combination! Good stuff! 73, Charlie,K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Sent: Saturday, February 22, 2014 10:08 PM To: Carl Braun; '160' Cc: w...@att.net; ad...@arrl.net Subject: Re: Topband: Shunt feeding the Skyneedle - new developments That is the type of report I really like to hear Carl. All that work has paid off in spades. As you increase the number of radials the VSWR bandwidth might decrease along with the R which is normal as the ground resistance decreases. Since it appears to work so well you might just leave it alone for awhile, operate and get a feel of how your signal compares with others. With the top loading Id say the tower is close to being a 1/4 wave and the perfect world impedance about 35-36 Ohms with the remainder as ground resistance. That will result in very decent efficiency. That cage you connected this morning sure changed the numbers from the single wire I was responding to. OK on the steel panel. The usual rule of thumb there is to space coils and variables at least their width away. There were some amps and tuners on the market that would have radically different tuning, and more power out in the amplifier examples, with the cover removed. Take a bow, Im impressed!! Carl KM1H - Original Message - From: Carl Braun carl.br...@lairdtech.com To: Carl k...@jeremy.mv.com; '160' topband@contesting.com Cc: ad...@arrl.net; w...@att.net Sent: Saturday, February 22, 2014 7:15 PM Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Carl and Topbanders Here are the latest details and I will try and be as thorough as possible. Good news! I built my gamma cage and the antenna now performs MUCH better. Here's where I stand: 90' Tri Ex Skyneedle shunt fed with the gamma arm at 67' and a three wire gamma cage with 10 separation between wires. My tower is grounded at the base via three 1 copper strap 1/8th inch thick and tied to a 1 1/2 copper pipe radial ring that measures 4' x 8'. The radial ring is also bonded to three 8' ground rods via 1 copper strap. Currently I have approx 30 ground radials screwed to the radial ring with copper clad stainless screws and then painted with copper paste. Some of the radials are formed from heavy control cable (similar to rotor cable) that are fanned out at the radial ring...converge into the Cable jacket, cross the 10' blacktop driveway and then emerge from the jacket and fan out across the property. The radials vary from 30' long to 100' long with three of them tying directly into the radial field of my 40m phased array. The three-wire gamma cage is made of 14ga stranded wire and converges into a cone with a single brass bolt holding all three ring lugs together 1.5' off of the ground at the base. An additional 14ga wire is also connected to the brass bolt and bolts to a porcelain feed through insulator that brings the feed into the metallic (STEEL) panel. A 14ga wire then bolts to the other end of the feed thru insulator and taps onto the input of the Cardwell air variable capacitor. The output of the capacitor connects to a SO 239 connector that is mounted to a 2 copper strap that travels down the enclosure where two brass bolts bolt the strap to the bottom of the panel. Under the panel, where the brass bolts emerge from the panel, two 2 copper straps connect to the brass bolts and then travel to the copper radial ring where they are terminated. Before the gamma cage I used a single 14ga wire dropped down from the gamma arm where it connected to the variable cap that was mounted outside my steel enclosure and sat on a plastic 5 gal pail. The gamma wire connected to the variable cap and then it was wired to the same standoff insulator I mentioned above and into an empty steel panel where I had the same SO 239 connector mounted to the copper strap and then to my grounding system. This config netted me 41 + j0 ohms. I was pretty satisfied with this scenario so I mounted my variable cap on a 3/4 thick piece of Plexiglas to the backplane via Teflon bolts inside the steel enclosure. When I did this I saw my analyzer jump to 45 -j11 ohms. No matter how much tweaking was done the lowest X on the analyzer was 11. Figuring I could live with that after making 24 contacts this morning I decided to move ahead with my gamma cage. When I completed the cage per the info above I left my analyzer set on the previous frequency setting of 1825 and saw the resistance jump and the X go out of site. Adjusting my variable cap (from approx 140 pf to 420 pf) rewarded me with a 42 + j0 reading. Inside the shack on the 1000D and the BIRD I see 1.1:1 Vswr at 1.800 MHz, FLAT 1.0
Topband: Shunt feeding the Skyneedle - new developments
All Topband list If you've followed my efforts to shunt feed my Skyneedle tower you'll know that I settled with a tap point of 67' and 30 or so of spacing with my feed point reading 42 + j0 ohms. This reading was taken at the interior of my 20 x 30 x 8 steel Hoffman enclosure with the variable cap located outside the enclosure sitting on a plastic 5 gal jug. The output of the variable cap fed into a ceramic feed thru insulator thru the panel to a copper L bracket that mounts the SO 239 connector that I hooked my coax cable to. Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. I use 1 meg ohm from the feed point to ground on my other verticals with NO change in MFJ analyzer readings. Any comments from the list on these problems? Thanks Carl AG6X _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments BTW
BTW. Carl I agree completely with Tom that there's no point in having a static-bleed choke on a grounded shunt fed tower! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments BTW-P.S.
By the way, Carl. it sounds like you might have eliminated a bit of series inductance when you moved the variable capacitor into the enclosure and you may have picked up a bit of shunt-C by moving it into the metallic enclosure, but you are so close to dead-flat 1:1, that it really doesn't matter. You could just tweak the variable C to minimize the reactance at the load, but -j11 is just fine! As I said earlier your 45-j11 resides near the origin of the chart on a 1.3:1 VSWR circle! Enjoy and have fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie Cunningham Sent: Friday, February 21, 2014 8:30 PM To: 'Tom W8JI'; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments BTW BTW. Carl I agree completely with Tom that there's no point in having a static-bleed choke on a grounded shunt fed tower! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
I'd think your Henry would match that just fine WITHOUT the Nye Viking tuner!! 73, Charlie. K4OTV -Original Message- From: Carl Braun [mailto:carl.br...@lairdtech.com] Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ 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: 2014.0.4335 / Virus Database: 3705/7115 - Release Date: 02/21/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps
Re: Topband: Shunt feeding the Skyneedle - new developments
Charlie The cap is no where near maxed out. I'm using approx 150pf of a 1050pf variable cap. Carl -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 6:37 PM To: Carl Braun; 'Tom W8JI'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower. It won't help a thing, so leave it out. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, Carl, you might pick up a littie less shunt C with the vacuum variable, and if it will provide more capacitance, it will probably allow you to get to j0. I guess if you don't have some other need for the high voltage capability of the vacuum variable, It should surely do the job! If you are at -j11, that means you have tken out enough inductance from the gamma line that you now need a larger capacitor to resonate it. Have fun! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 10:31 PM To: ZR Cc: Charlie Cunningham; 160 Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks guys The j11 ohms is the best I can get period. I was able to get j0 when the cap was outside of the steel enclosure with a better bandwidth. Maybe I should throw my $400 enclosure and find a fibergla$$ enclosure. But as others have indicated I should probably just live with it. Do you think a smaller (physically) vacuum cap would have less interaction with the steel enclosure. The one I have is only 3 round and 6 long. The air variable I'm using is 13 long and 7 round at mesh Carl AG6X Sent from my iPhone On Feb 21, 2014, at 7:11 PM, ZR z...@jeremy.mv.com wrote: The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between
Re: Topband: Shunt feeding the Skyneedle - new developments
Well, that would surely suggest that you should be able to reach j0, by increasing the series capacitance, Carl, unless there's a shunt-C term that has entered the picture after mouning that big variable capacitor in the metallic enclosure. But, again, why bother! 73, Charlie, K4OTV -Original Message- From: Carl Braun [mailto:carl.br...@lairdtech.com] Sent: Friday, February 21, 2014 10:39 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Charlie The cap is no where near maxed out. I'm using approx 150pf of a 1050pf variable cap. Carl -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 6:37 PM To: Carl Braun; 'Tom W8JI'; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard. Lots of stateside calling stateside Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 5:21 PM To: 'Tom W8JI'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, Carl I plotted your 45-j11 load on a Smith Chart (normalized to 50 ohms) and it's very near the origin on a 1.3:1 VSWR circle. Since you have a relatively short feedline of LMR-400, You should be able to just tune it out at the transmitter end of the line, and the LMR-400 line will be operating at such a very low SWR (around 1.3:1 that the excess loss from a 1.3:1 VSWR at 160 is completely trivial and negligible! It may not be completely intellectually satisfying to have -j11 of reactance at the load, but it should match easily and the antenna should work very well! Enjoy! Sounds like that Array solutions static bleed is not as high in impedance as we might wish! A large resistance might give you more satisfactory results! GL! Enjoy! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Friday, February 21, 2014 8:02 PM To: Carl Braun; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Since then I've moved the variable capacitor inside the panel and mounted it to a ¾ think Plexiglas sheet mounted to the back plane with nylon bolts and washers. There is a 1 air gap between the Plexiglas and the backplane. I now have seen the 42+j0 ohms change to 45 - j11 ohms...that's the lowest reactance I can tune the capacitor for. Not really sure if its +j11 ohms or - j11 ohms but I assume if the reading was + j11 I could continue to tune it out with the capacitor but I cant. Does the capacitor not play well with a steel enclosure? Any enclosure will change things, especially a metallic enclosure. Just readjust the cap. The other strange situation I'm experiencing is when I connect my Array Solutions static bleed choke to the feed thru insulator at the outside of the panel to ground the resonant frequency jumps to 2.014 MHz at 25 +j0 ohms...remove it entirely and I'm back to my 45 - j11 ohms. The choke is completely unnecessary with a shunt feed tower
Re: Topband: Shunt feeding the Skyneedle - new developments
I'm working on the radial field weekly. Here is a theoretical question that results from my particular QTH. The Skyneedle is situated near a secondary blacktop driveway that is in the back of my property. I have to run radials over the blacktop to the rest of the property and, in order to keep things kind of neat, I'm using multi-conductor rotor cable as radials that travel over the blacktop. I have both 6 conductor and 3 conductor control cable that I'm using. I strip back the jacket at the radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper pipe I'm using as a radial ring around the base of the 'Needle'. Then the radial wires converge back into the cable jacket then travel across the 10' blacktop driveway and then they are removed from the cable jacket where they fan out into the dirt and are buried. Most of these radial wires are 60' to 100' once they leave the jacket. Any problem with what I'm doing here? I understand that it would be better if they fanned out directly from the base but I can have 50+ wires traveling over the blacktop. I was even considering getting an asphalt blade and cutting some channels into the blacktop...burying the jacketed cable into the asphalt and then sealing then in so I'm not running over them or tripping over them when playing Frisbee with the hound. My Guatemalan yard worker has been burying radial wires for the last month and thinks that I'm LOCO but he likes getting paid at the end of the day. As we speak I have a total of 34 radials with the shortest being 30' with the longest at 100'. Most of them are 60-70'. Four of them are tied into my 40m phased array radial field comprised of 90-100 radials under each antenna ranging from 40' to 80'. I can change the height of these verticals from 33' for 40m to 66' for 80m. 1/2 wl spacing on 40 and 1/4 wl spacing on 80. Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 7:36 PM To: 'ZR'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have a Nye Viking monster tuner but I hate to use it as my Henry amp seems to load strangely when I have it inline so I think I'll just live without it. Can I add some coax (coiled) to bring the X down on the -j11 reading? I did this with the old Telrex and brought the X right down and out of the pic. I'm sure Ill need much more than I would on 14MHz but I think I'd like to try anyway. I'm still going to drop the tower down and add two more gamma wires to create a cage and I still have the option of pulling the gamma wire(s) away from the tower another 8-10 inches to add a few more ohms to the equation. I'm having fun with the experiment. Right now I'm hearing the beginnings of the SSB contest with N7GP, WD5COV, W6YI with the big signals so far. XE is the only DX I've heard
Re: Topband: Shunt feeding the Skyneedle - new developments
Hi, Carl Well, I think that what you are doing with your radials should be OK. I guess I'd rather get them under the asphalt if I could where they wouldn't get torn up or b a trip hazard. BTW I I was playing with your match on the Smith Chart and if you'll add about 1 uHy inductance in series with the connector (SO-239?) where you feedline leaves the enclosure, that will take you to 45 +j0, but I'd be concerned about incurring more losses in the inductor than any tiny mismatch loss from the -j11 term. I probably wouldn't do it. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 10:56 PM To: Charlie Cunningham; 'ZR'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments I'm working on the radial field weekly. Here is a theoretical question that results from my particular QTH. The Skyneedle is situated near a secondary blacktop driveway that is in the back of my property. I have to run radials over the blacktop to the rest of the property and, in order to keep things kind of neat, I'm using multi-conductor rotor cable as radials that travel over the blacktop. I have both 6 conductor and 3 conductor control cable that I'm using. I strip back the jacket at the radial ring...fan out the wires 3 apart and attach them to the 1 1/2 copper pipe I'm using as a radial ring around the base of the 'Needle'. Then the radial wires converge back into the cable jacket then travel across the 10' blacktop driveway and then they are removed from the cable jacket where they fan out into the dirt and are buried. Most of these radial wires are 60' to 100' once they leave the jacket. Any problem with what I'm doing here? I understand that it would be better if they fanned out directly from the base but I can have 50+ wires traveling over the blacktop. I was even considering getting an asphalt blade and cutting some channels into the blacktop...burying the jacketed cable into the asphalt and then sealing then in so I'm not running over them or tripping over them when playing Frisbee with the hound. My Guatemalan yard worker has been burying radial wires for the last month and thinks that I'm LOCO but he likes getting paid at the end of the day. As we speak I have a total of 34 radials with the shortest being 30' with the longest at 100'. Most of them are 60-70'. Four of them are tied into my 40m phased array radial field comprised of 90-100 radials under each antenna ranging from 40' to 80'. I can change the height of these verticals from 33' for 40m to 66' for 80m. 1/2 wl spacing on 40 and 1/4 wl spacing on 80. Carl AG6X -Original Message- From: Charlie Cunningham [mailto:charlie-cunning...@nc.rr.com] Sent: Friday, February 21, 2014 7:36 PM To: 'ZR'; Carl Braun; '160' Subject: RE: Topband: Shunt feeding the Skyneedle - new developments Well, if I recall correctly, Carl, Carl said his feedline was about 70' of LMR-400, so even at 2 2:1 or 2.5:1 VSWR, the excess losses in 70' of LMR-400 at 1.8 MHz are almost 0, so if he can match it OK at the transmitter end of the line- no real point in making heroic efforts to achieve a perfect match! He'd gain more by working on his radial field, and he really should do that before doing any more tuning because improving the radials WILL affect the antenna impedance. 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Friday, February 21, 2014 10:11 PM To: Charlie Cunningham; 'Carl Braun'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments The only benefit of getting it better would be a bit more 2:1 VSWR bandwidth to keep the amp happy but even then there is sometimes a gotcha when tuning an antenna. Carl KM1H Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Well, you can do all that, Carl But if your series variable capacitor is not maxed out (fully meshed) if you can increase the capacitance enough to get to j0, you would be at 45 +j0 and on a 1.1:1 VSWR circle. No point int trying to do better than that!! Otherwise, just increase the series capacitance to bring that -j11 as close to j0 as possible and take that! You'd be so near perfect that there would be no real point in going further! Your time and efforts might be better spent working on your radial field! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Carl Braun Sent: Friday, February 21, 2014 8:46 PM To: Charlie Cunningham; 'Tom W8JI'; '160' Subject: Re: Topband: Shunt feeding the Skyneedle - new developments Thanks to all who replied Tom W8JI, your comments on the metallic panel and the static bleed choke make sense. I was so pleased with the FLAT SWR reading with the variable cap outside the panel but I guess I can live with the slight SWR. (Thanks Charlie K4OTV). I have
