My first thought is “Heat”!
Sent from my iPhone ...nr4c. bill > On Jul 15, 2020, at 4:43 AM, Ray Spreadbury via Elecraft > <elecraft@mailman.qth.net> wrote: > > Hi > > I was a member of the UK HQ team for this 24hour IARU event last weekend and > was one of the two Ops on 40M SSB. > > We took it in turns to be the Run station every 4 hours and I was using a > 40M 2-El yagi at 60ft. I noticed that every 30-60mins, I needed to do a > re-tune on the KPA1500 to keep the SWR at or near to 1.1:1, as it seemed to > gradually creep up over time. The amp temp peaked at 70C but was mostly at > about 55C. The SWR never got above 1.5:1 using KPA1500 screen but I know > that the yagi was really presenting about 1.6:1 at the run frequency. When > not operating as the Run station the other Op was in Partner mode spotting > mults & helping with call identification. > > We were using the WinTest logging program as this enables us to private > network with the other UK HQ stations (one on CW & one on SSB for each > contest band ie. a total 12 stations at any one time, plus Partners). > Because of Covid, this year we were all single Ops working from home rather > than just a few multi op stations. > > My K3S & the KPA1500 worked faultlessly for the 24hours as did Wintest but I > wonder what was the cause of the SWR increasing over time & needing a > re-tune? > > 73 Ray G3XLG > > ______________________________________________________________ > 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 n...@widomaker.com ______________________________________________________________ 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
