Author Topic: End-fed wire question. what about counterpoise length?  (Read 11550 times)

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KC9TNH

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Re: End-fed wire question. what about counterpoise length?
« Reply #15 on: March 25, 2012, 08:17:15 AM »
Was wondering if there is some ratio of radiator-to-counterpoise that is desired when using an end-fed horizontal wire.Bob
Bob, sent you an email as well but, looking back through the thread to your original question, some review of notes and talking with an Elmer (who has tuned his well system for his vertical on the hill, BTPost's nice solution on steroids), in terms of a counterpoise it seems your ratio you'd be looking for - particularly in a field situation -  is 1/4-wavelength of wire for the lowest frequency you're operating at. One can run different lengths from a tuner's ground lug, or facilitate removable/attachable lengths given transmit needs. The latter is attractive to me if one is working multiple bands since one band's 1/4 wave is another band's longwire. May help avoid the weird multiple issue that drives some tuners nuts. So strictly in terms of your original question that ratio would be a starting point, remembering that your end-fed wire has a vertical component to it.

Just what I was able to find out about the question, looking over stuff I'd forgotten when I put up an 80m dipole. Sometimes I miss my mind.
  :-[


 

BTPost

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Re: End-fed wire question. what about counterpoise length?
« Reply #16 on: March 25, 2012, 02:00:36 PM »
The real issue with building a Good RF Ground, is that any "Tuned Counterpoise" type system, is just that, "tuned" for a specific Frequency, and becomes very lossy, as you move away from the Tuned Frequency. This is where HAMs get themselves in trouble as they think that a single, or even multiple Lengths of Ground Wires, will act as a Good Low Impedance RF Ground cross a wide Bandwidth in the HF Spectrum. In the Commercial HF Comms that I have worked in, we had to design and build a REAL Low impedance, Wide Bandwidth, RF Ground system, that would cover the whole HF spectrum, and then setup the channelized Antenna Tuner, for each of the installed Frequencies, and Bands to tune the single Antenna  for each of those  Frequencies and Bands. This allowed the unlicensed or Minimally Licensed Radio Operators to communicate without having to worry about any Antenna Tuning issues, as they were dealt with during Installation. Modern Auto Antenna Tuners have come a long ways since they introduction Post Korean War. The modern Binary Switched, Lump Constant, Microprocessor Controlled Auto Antenna Tuners around today, were the brainchild of of Bill Schilb, of Motorola Fame, who brought the technology west. First to Northern Radio Co. and then to Berlonix Radio. The Technology was refined by Mark Johnson/Bill Forgey design, of familiar Forward/Reverse Power, Lead/Lag PhaseDetector, and accompanying Tuning Algorithm, first seen in the SEA1601, and refined further in the SEA1612C/SEA1630 Autotuners, on which the SGC, Icom, and everyone else's Binary Switched, Lump Constant, Microprocessor Controlled Auto Antenna Tuners are based.  These are very good Autotuners, HOWEVER to function properly, THEY REQUIRE, a REAL Low impedance, Wide Bandwidth, RF Ground system. Without that, they get very poor results, in many various band chucks, when tuning thru the whole HF Spectrum. This is fast becoming a "Lost Art" as Commercial HF Comms has become a Dead or Dying Technology.  Just Say'en... YMMV....
Bruce in alaska AL7AQ

KC9TNH

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Re: End-fed wire question. what about counterpoise length?
« Reply #17 on: March 25, 2012, 02:20:45 PM »
That's good stuff Bruce, thanks.
Is that a 182 in your avatar?

BTPost

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Re: End-fed wire question. what about counterpoise length?
« Reply #18 on: March 25, 2012, 02:25:11 PM »
Yep, Notice the Tundra Tires.... not those whimpy FlatLander tires you see down south..... Plane is NOT mine, It belongs to a local Bush Pilot that used to fly in here, before he crashed on a hunting trip, up in the Brooks Range, a few years back....
Bruce in alaska AL7AQ

RazorCityDen

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Re: End-fed wire question. what about counterpoise length?
« Reply #19 on: March 25, 2012, 04:08:46 PM »
Great Thread!  8)