One comment to add to Don's is that the length of the common wire must be SHORT in terms of WAVELENGTH. As Don said, you want the counterpoises to be close to a resonant 1/4 wavelength on each band
Six feet is small on 80 or 40 meters, but it starts becoming significant on the higher bands. For example, on 10 meters you only need an 8-foot counterpoise. Hooking other counterpoises only two feet from the high-impedance far end will drastically detune it. I doubt if you can get it to show any sort of resonance on 28 MHz. It may well be an issue as far down 14 MHz as well. If you want to band-hop as fast as your KAT100 can switch between them, arrange separate counterpoises on the higher-frequency bands. Instead of running outdoors, try running them along your baseboards with each one going directly to the rig. Another way to deal with that is to use a small single-ended matching network just like you'd use with any end-fed antenna except the 'hot' lead to the transmitter connects to the transmitter case or ground, of course. Then you adjust the network for maximum current into the counterpoise for the band you are using. SWR is not any concern, just maximum RF current. How do you measure the current? Put a small flashlight bulb in series with the counterpoise temporarily to tell what adjustment produces the best current. Unless the counterpoise is very short in terms of wavelengths, one adjustment will be FB for an entire band. Once you've found it, short out the bulb to keep it from burning out. Often a watt or less will produce a lot of light! Once you know the settings you can not them so you can simply reset the controls to the right places for each band. For a matching network, a simple tapped coil and series variable will work. Some companies make these circuits all built up and ready to hook up, complete with a wiggly-meter RF current indicator. MFJ's "Artificial Ground" is one. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
