I agree that the balun should be checked but that it is likely NOT the issue here as it works on the other bands. If it is replaced, using a 1:1 common mode choke (not just a voltage balun or series of ferrite cores on the coax) would be a good thing to try. I opted for the 10KW rated version as I never want to have an issue and I only run <700 watts.
To make clear an earlier statement of mine, without the added coax, the untuned VSWR was 24:1, with the added coax it is under 10:1. The KAT500 tuned the wire in both cases here but in the original configuration tuned my EDZ to 1:1 at low power then faulted out at anything above 300 watts. Adding more coax solved the issue (I tried a shorter run too, no change) by shifting the 80M voltage peak to someplace else on the feed. Is your wire antenna insulated or bare? Is there a chance that it is arcing (wet tree, mast ???)? With the voltages produced at QRO, the potential is there. Ditto your window line, insulated or bare? Is rain or snow impacting it? You'd know because it would need retuning. Rick wa6nhc -----Original Message----- From: David Gilbert From a troubleshooting point of view jumping right to the balun requires making a lot of assumptions, most of them unwarranted given what little we know so far from his post. More importantly, a balun with a ruined core is going to look bad for SWR no matter what power level is fed to it, and he says that things look fine at 300 watts but go south at 400 watts. That's an arc over problem somewhere ... Dave AB7E ______________________________________________________________ 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
