Mark, I had the same problem except on 20 meters. I applied some RFI elimination fixes and the problem went away.
73, Chas W1CG At 06:52 PM 8/1/2007, Mark Amos wrote: >Flexers, > >I'm having a transmit problem with my SDR1000. >Here's the lineup: >SDR1000 with all the options (ATU, PA, RFE, transverter) >Edirol FA66 >USB cable >All audio lines isolated between computer, Edirol and the radio. >Ferrite clamps on all of the audio and control cables. >Radio gear, computer, tuner, etc. all connected to common shack ground. >Palstar tuner >Butternut vertical > >The problem is that on 40 Meters, when I key the transmitter, the >forward power goes up over 200 watts with any setting over >10W "drive" setting. At that point the SWR (as shown on the Palstar >and on PowerSDR) goes through the roof, and the power >output from the Flex does as well. It ONLY happens on 40 meters and >ONLY when connected to the antenna (i.e. there is no >problem transmitting into a dummy load.) > >I substituted a dummy load at each location between the transmitter >and the antenna and thus ruled out issues with the coax, >bulkhead feedthroughs, tuner, etc. > >So, it appears to be an antenna problem (perhaps a short or open >that only shows up at power above 10 watts...) > >What puzzles me is the SDR1000 cranking out such high power (as >reported by PowerSDR, the tuner and an in-line wattmeter) under >a high SWR condition. PowerSDR shows "High SWR" on the panadapter >display, but doesn't cut back the power. > >So, here's my question: would an RF feedback / antenna problem >account for this behavior? > >Mark > > > >_______________________________________________ >FlexRadio mailing list >FlexRadio@flex-radio.biz >http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >FlexRadio Knowledge Base: http://kb.flex-radio.com/ >FlexRadio Homepage: http://www.flex-radio.com/ _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
