Actually making an end-fed wire 1/2 wavelength long is ideal, from an antenna efficiency standpoint, because such an antenna does not need a good ground return (it needs something to keep the rig from floating up to a high RF potential that causes the tuning to shift as one touches the rig or moves wires, but that has little effect on the efficiency of the antenna itself).
The problem is that very large RF voltage are developed at the end of such a wire - well beyond what any compact or semi-compact tuner that doesn't use big air variable caps can handle. So we compromise. It's tough to specify an impedance range for a tuner. I'm not surprised it's not obvious in the manuals. Basically, throw up what you can and see if it works. Most wires will work. And, if needed, you can consider adjusting the length a bit if it doesn't . 73 Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lynn W. Taylor, WB6UUT Sent: Friday, March 08, 2013 8:52 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] [KX3] Portable Antenna question Of course -- and experimenting is half the fun. I expect to go through a lot of wire playing. I'm pretty good with the theory -- and as everyone has said, it makes sense to avoid feeding the end of a half-wave wire. I haven't yet found the impedance range for the tuner in the manuals. I'm still reading. I also moved not too long ago, and a lot of things (like my antenna book) are in a box somewhere. I'm still searching. I think my Par EF-20 is in one of those boxes, as is a nice chunk of coax with a BNC on one end, and a PL-259 on the other. I did find my straight key, but I haven't been on CW this millenium. ... and I've got 100' of Wireman #534 due to arrive tomorrow. I can always buy more. -- Lynn ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html