Like others have said Even though your analyzer says the antenna is ok, that is only one part. It can still be part of the problem at 1500 watts and if memory serves me well, that is about 275V (RMS) at 50 ohms.
Something could be breaking down at that voltage so a good visual inspection would help. Look for arcing at each connector, Ununs, Baluns, etc. Mike va3mw On Fri, Sep 27, 2019 at 9:18 AM Bob McGraw K4TAX <rmcg...@blomand.net> wrote: > Check for burn marks or carbon traces, both on the inside and outside, of > the SO-239 connectors. These may look good with the antenna analyzer but > fail under power. > > I've also had PL-259's arc from center pin to shell on the inside. These > required removal/ disassembly of the coax in order to actually find the > fault. > > In all cases, once a flashover occurs, replacement of the connector is the > only solution. > > Bob, K4TAX > > > Sent from my iPhone > > > On Sep 27, 2019, at 6:00 AM, John Langdon <woyb10...@outlook.com> wrote: > > > > If it also happens with a dummy load, and the antenna analyzers shows > the same graph as before for R, X, then it is likely one of the connectors > between the KPA1500 output and the antenna. The one such problem I had was > old jumper I had put in to add an SWR bridge/monitor. It looked okay, and > was finger tight, but when I replaced it in an A/B test, the problem went > away. > > > > The other time, the antenna had changed its impedance curve, but was > still 'okay' and the tuner was trying to retune for it. > > > > 73 John N5CQ > > > > > > -----Original Message----- > > From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> > On Behalf Of Jim Brown > > Sent: Friday, September 27, 2019 4:19 AM > > To: elecraft@mailman.qth.net > > Subject: Re: [Elecraft] KPA-1500 failing on 160...AGAIN! > > > >> On 9/26/2019 10:26 PM, Peter Dougherty wrote: > >> Any idea where to start looking here? > > > > And if it's a vertical, what about the radial system? > > > > 73, Jim K9YC > > ______________________________________________________________ > > 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 woyb10...@outlook.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 rmcg...@blomand.net > > > > > ______________________________________________________________ > 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 va...@portcredit.net > ______________________________________________________________ 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
