The average power of voice is far below that of CW. If there is a corroded connection that is heating up and failing, then cooling and reconnecting, it could be happening with CW and not SSB. Try reducing the output of the KPA500 to 100 watts on CW and see if the trouble goes away.
We one time had a failure something like this at NY4A. The trouble was traced to a male/female UHF elbow coax adapter, one of the cheeep, cheeep kind that makes the center connection around the bend in the elbow with a spring in the center. This is easier to manufacture than the good kind, which is why they are cheeep. Over time these springs heat up, lose their tension, corrode at the connection points, and display weird symptoms like you describe. Worth checking out. The only reliably non-spring elbows are Amphenol's, where the male center pin screws into the conductor from the female side. Once you know what to look for, you can tell in an instant. Throw all the spring based elbow coax adapters into the trash. They cannot be rehabilitated. If you get any from a supplier, send them back and demand a refund. I walked around a hamfest and easily found 25 of the Amphenol types to take home. You can also get the same kind of symptoms from a PL259 where the braid was not soldered, or has undergone exceptional amounts of flexing, or has lived for a long time at a current max at a high current place. These issues are exacerbated by cheeep coax with lesser amounts of conductor in the shield. Good luck & 73, Guy K2AV On Fri, Nov 28, 2014 at 10:13 PM, <tom...@videotron.ca> wrote: > > > Ok more detail. If I set Tune power to 30w and then press Tune, then > with the KAT500 in manual it will tune down to 1.2:1. HOWEVER, if I leave > it there with the tune power on,the KAT 500 starts showing 1.2, three > seconds later, an bunch of relays click, the power SWR scale lights up, the > fault line comes on. Then all of a sudden, it is steady again. Shows > 1.2:1.. Three seconds later it all repeats. Now if I do it with CW, same > thing is happening although it's more difficult to see what's going on due > to the intermittent signal.. So it's something with the KAT500 and the > antenna. But, voice is perfectly fine! > > > > > > > > > > > ______________________________________________________________ > 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 k2av....@gmail.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 arch...@mail-archive.com
