Any more info on this? 73 Jim Allen W6OGC > 25 amps at 14 volts is 350 watts. That is an awful lot for a radio that is > supposed to be putting out only 20. I would expect at most 2 to 3 watts drain > at 20 watts TX output. Something is definitely going on here. may load While > I don’t suspect the antenna, have you tried testing into a good 50 ohm dummy > load to see if you can duplicate the issue? You might also look for bad > solder joints between the PA transistors and the antenna. And, just in case, > check to make sure there are no bad (arcing) connectors in the antenna path. > Perhaps W3FPR might be around on the Easter Sunday for some suggestions? - > Jack, W6FB > > On Apr 16, 2017, at 7:51 AM, Steve Kavanagh via Elecraft <elecraft at > > mailman.qth.net> wrote: > > This one cropped up just today, with no > > significant change in my home station setup, using a K2/100 on 40m using a > > low inverted Vee. > > Sometimes (typically every other or every third time, > > but randomly), when pushing (and holding) the tune button with the power > > set to 11 watts or more, I get a high reflected power message on an antenna > > which is matched at low power. The power supply voltage reads about the > > normal 14V and the ammeter in the power supply is pinned at 25 A (or more) > > when this happens. An external SWR meter reads lots of reflected power. > > Everything unplugged from the rig except the power cable and the coax to > > the external SWR meter/antenna tuner/antenna. It's fine on a dummy load. > > > > I'd suspect a simple RF feedback problem, except that with 100 watts of > > CW everything is perfectly normal. The problem occurs only when using the > > tune button around the nominal tune-mode 20 watts, so the external SWR > > meter reading implies that the PA is probably oscillating at some frequency > > where the antenna is not matched. I haven't tried any other bands yet, but > > since there does seem to be RF feedback involved, I'm not sure they will > > tell me much of a diagnostic nature. > > Any ideas as to what might be > > happening and how to stop it? > > 73, > Steve VE3SMA > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected]
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