sorry your still having trouble Can't say for sure but could very well be some funky grounding.
check it into a dummy load to at least eliminate the antenna System If you can also try to vary the length of the coax going from the rig to amp (sometimes helps) using a speech compressor? measure your grounds and any external power supplies used for ac leaking over , maybe a long shot easy to check w/vom goodluck N2EHG On Jul 18, 2009, at 11:28 AM, K2QI wrote: > Björn's description of the KPA3 behavior sounds incredibly similar > to issues > I've been experiencing when only operating in sideband. My problem > however > isn't so much of an initial low power transmit, but what appears to > be the > complete opposite. Some of you may recall the post I submitted to the > reflector several days ago about strange RF activity and my K3. In a > nutshell, my SWR alarm on my wattmeter will trip upon initial > keydown when > operating in sideband and the linear is on. It functions fine on > the other > hand if I key down with a continuous carrier.. even up to 1200W. The > exciter drive level doesn't seem to make too much of a difference > UNLESS I > turn the power output to 12W or less. The moment I switch back to > 13W or > higher and the KPA3 is in line, the problems begin. Looking at my > wattmeter > in peak mode shows an initial burst of power when keying down. > After a few > seconds, the power drops back to a normal level. I have a theory that > there's some sort of RF burst in sideband mode upon initial keydown; > perhaps > the KPA3 oscillates for just a few seconds and transmits off- > frequency until > it stabilizes. This is just a theory though. > > I'm still playing with my RF grounding and isolation to fully hope in > eliminating all other possibilities before pointing the finger at > the K3. > > 73 de James K2QI > > > 2009/7/18 Björn Mohr b...@broadcast.se > >> >> This problem has been around for some time with my K3. What happens >> for me is that when I set the power to specific level and push TUNE >> the radio stabilizes at that preset level. Then when keying and begin >> talking the power level is a lot lower that verified with TUNE. After >> a few seconds the power peaks are in the vicinity of the preset >> level, >> but sometimes peaks are reaching above the preset level which makes >> me >> reluctant to mess with TXG VCE. Another observation is that this >> problem is only with the PA in line, taking power below 12 watts >> seems >> to eliminate the issue. >> >> Earlier the problem was reversed as power overshot the set level in >> SSB, now I am less worried but seeing the issue solved would provide >> some comfort when using the amp. >> >> I am also using a factory calibrated LP-100A to verify my >> measurements. >> >> >> 73 de Björn, >> SM0MDG >> SE0X >> >> ______________________________________________________________ >> 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 >> > ______________________________________________________________ > 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 Myles Landstein myles.landst...@gmail.com please note my new email address dti will soon be eliminated , gmail is my new home update your dir ______________________________________________________________ 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
