I hate to say this but cable experts does not have a stellar record with their installed connectors. I would cut them off and install new ones.
73 Greg On Jun 4, 2012 10:55 AM, "Rick Johnson" <[email protected]> wrote: > Jump back down to Ron's input. > I had that exact same scenario with my OCFD. As soon as I transmitted > any length of time on CW above 250W the SWR would jump up and the > KPA500 would fault. > The problem was a too small torroid 4:1 balun. I bought a 5KW balun > from Hy Power Antennas and the problem went away. > Just because the balun is rated to 5KW doesn't mean you have to use > that much power. > > 73, > Rick W3BI > > -----Original Message----- > From: [email protected] > Sent: Monday, June 04, 2012 1:47 PM > To: [email protected] > Subject: Re: [Elecraft] [K3-KPA500] SWR jumps up with 5 second key down > > My bet will be on a bad connection someplace after the amp. With power > something is shorting ... could be in coax connector, antenna, etc ... been > through that. Once had found an elevated radial on 160 inverted "L" had > dropped and touching a tree limb was the problem. > > 73, Mike > > -----Original Message----- > From: Ron D'Eau Claire > Sent: Monday, June 04, 2012 12:33 PM > To: 'ai6ii' ; [email protected] > Subject: Re: [Elecraft] [K3-KPA500] SWR jumps up with 5 second key down > > Mark has an excellent point, especially if you have a ferrite core > transformer (balun, etc.) somewhere in the antenna system. One thing that > can cause that behavior is heating of the toroid core. At a certain > temperature, the core's magnetic properties change dramatically, changing > the inductance and so causing the SWR to change. > > Ron AC7AC > > -----Original Message----- > > What happens when you run the KPA-500 into a dummy load? If all is well, I > would guess that something is changing under high power and affecting the > load. > > -----Original Message----- > From: ai6ii <[email protected]> > To: [email protected] > Date: Mon, 4 Jun 2012 10:00:54 -0700 (PDT) > Subject: [Elecraft] [K3-KPA500] SWR jumps up with 5 second key down > > > I have installed a new antenna and have strange changing swr. When testing > with RigExperts meter I find good resonance at say 15m (21.200). With the > K3 > at 100 watts reading is 1 bar on K3 meter and 1.0 on KPA500 (STBY). When I > bring the amp online and drive it at 200 watts, all is still good even with > a 15 second key down period. Driving the KPA500 to 275 watts, still okay > with key down, although the KPA500 meter now shows 1.1. BUT when I increase > the drive a little more (300 watts) the swr jumps up to 2.5+ and the KPA500 > shows REFL HI and drops into STBY. > > And here is the kicker...NOT ALL THE TIME! > > So I think it has to be in the coax. But the 75feet of RG213 is brand new > premade from Cable Xperts with the connectors. > > I will try a different coax. Any other suggestions? > > ..mike > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > 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:[email protected] > > 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
