I have considerable experience with both commercial and home-brew loops. As others have said, it is tough to obtain maximum efficiency - the two largest contributors to loss being resistance in the tuning capacitor and ground losses. A couple of wires soldered to the tabs of a receiving capacitor with a sliding contact to the rotor will have large losses and several commercial antennas are made this way. Since small loops use vertical polarization, unless you are over really good soil or sea water, they need to be high enough to minimize earth losses - typically 0.1 to 0.2 wavelengths.
I modified a portable aluminum loop by enlarging it to 5-foot diameter and improving the capacitor arrangement. It worked acceptably well and I was able to make contacts on 20, 30 and 40 meters with a KX3 barefoot. However, I find that almost any full-size antenna works better and the difference is usually one to two S points. When operating portable, I now deploy a telescopic 40-foot fiberglass pole with a wire antenna - vertical or loop. I continue to use two small transmitting loops in my HOA restricted home shack. Mike AF7ON -- View this message in context: http://elecraft.365791.n2.nabble.com/Experiences-using-a-portable-HF-loop-tp7629785p7630030.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
