Just as a bit of anecdotal data, I am feeding a 20m dipole with 1200 watts through 600-ohm open line on 40 through 10 meters. The SWR on 40 meters approaches 100:1 (the line is short, but I am still eating about 2.2 dB loss).
Anyway, this presents a very difficult problem for most tuners -- and if you try it with an unbalanced tuner plus balun, even a 5kW DXE balun gets too hot quickly. My solution was to cancel the reactance by switching in external capacitance or inductance as needed on 'difficult' bands (40 and 30 meters) and then letting a commercial autotuner take it from there. Some day I'll put the matching circuits at the antenna and get the 2.2 dB back. Vic 4X6GP > On 21 Apr 2017, at 22:59, GRANT YOUNGMAN <[email protected]> wrote: > > 2. There are many ways to bring any antenna/feedline's Z0 to something that > a reasonably-sized affordable auto-tuner can handle at not too great a feed > line SWR. Not the least of which is to feed a commercial old fashioned > mechanical tuner with heavy-rated components that can handle the reflected > power from whatever bobbie-pin you’re trying to match without just melting > all the plastic in the tuner if you key down for a bit too long. ______________________________________________________________ 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]
