Why on earth bother with the tuner in the radio, when you've matched the antenna to the feeder at the feed point?
All your doing is adding extra loss to both the TX and RX path. If the match (indicated by VSWR at the rig end of things) is changing during the 15 second FT8 transmission period, that could be stressing a PA and or PSU, and you're hearing an over-temp warning from something, if that's what it is. Either case, the cause of the wandering VSWR (if that is it) or the lack of cooing to the PA/PSU needs sorting out. Lastly, most people running JT (and other digi) modes, don't run the rig at full power, but between 25 and 50%. 50W is half an S point down on 100W. Those that do run QRO on those modes, do so with a "Large" PA, also under run, to keep it very linear (for the modes that need it) and/or within it's dissipation/duty cycle ratings. 73. Dave G0WBX. On 30/07/17 20:26, elecraft-requ...@mailman.qth.net wrote: > On 7/30/2017 9:16 AM, MaverickNH wrote: >> I'm using a K3S/100 with ATU to drive a 43ft vertical with remote ATU at >> base. To operate, I typically bypass the K3S ATU, tune the remote ATU to 1:1 >> on 20m, then turn the K3S ATU to auto and tune again to 1:1 reading on the >> K3S. Running WSJT-X FT8 digital mode at 63W, all is fine, but if I run 100W >> too long I sometimes hear an alarm and turn power back to 63W (the alarm >> stops) or the K3S just shuts down. I'm not sure where the high-pitch alarm >> is coming from - I have a nearby Yaesu FP3010A Linear PSU but the manual >> mentions nothing about an alarm. Nor does the K3S mention an alarm. I see no >> High SWR warning on the K3S display. The PSU does not turn off. ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
