>From the Amphenol data sheet, UHF connectors are rated for 500 V peak, so they >are marginal for use at that power level. Type N connectors are rated at 1500 >V peak.
https://www.amphenolrf.com/connectors/uhf.html https://www.amphenolrf.com/connectors/n-type.html wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 27, 2019, at 7:41 AM, Jim Miller <j...@jtmiller.com> wrote: > > Although the RMS voltage is pretty high. The peak voltage is higher > especially if SWR isn't 1:1 along the transmission line. > > It could easily be above 1Kv and causing arcing. > > 73 > > jim ab3cv > > > On Fri, Sep 27, 2019 at 10:35 AM Michael Walker <va...@portcredit.net> > wrote: > >> 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 j...@jtmiller.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 wun...@wunderwood.org ______________________________________________________________ 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
