I think the issue is to be sure the tuner powers up with or after the K3. But, mine turns on first and then the K3 later with no issues. I have pretuned it and run it on manual if that makes any difference.
Chuck Jack Hawley KE9UW Sent from my iPhone, cjack > On Aug 20, 2019, at 3:27 PM, Ken K6MR <[email protected]> wrote: > > “The KAT500 can be {should be} powered from the radio 12V supply.” > > > > Interested why this is true. Can the KAT500 tell the difference between > Elecraft 12V and Generic 12V? Seems odd. > > > > I ran two KAT500s on generic 12V from a DIN rail power supply for 5 years. > Necessary because the tuners and the amps were remoted in a closet 20 feet > from the operating desk. No problems. > > > > Ken K6MR > > > > > > ________________________________ > From: [email protected] <[email protected]> on > behalf of Bob McGraw K4TAX <[email protected]> > Sent: Tuesday, August 20, 2019 12:59:11 PM > To: [email protected] <[email protected]> > Subject: Re: [Elecraft] KPA500 Coax size requirements > > Carter: > > The KAT500 can be {should be} powered from the radio 12V supply. I > don't suggest a separate wall wart. > > The KPA500 can be powered from either 120VAC or 240VAC, your choice. It > should drive on all bands with 20 to 30 watts output from the K2 to > reach full 500 watts output from the amp. > > As to coax, yes RG-8X is OK up to 30 MHz as long as the SWR is low. The > Belden Power rating is 1000 watts up to 10 MHz, 370 watts at 50 MHz. > Loss is 0.9dB / 100 ft @ 10 MHz and 2.1 dB / 100 ft at 50 MHz. These > power ratings are matched conditions. > > What is the SWR on your wire loop on the feed line for all bands? Per > Belden, the UL voltage rating is 300 V RMS. Thus 500 watts at 50 ohms, > i.e. 1:1 SWR, is 158 volts. However, 500 watts into 500 ohms, i.e. 10:1 > SWR, is 500 volts. So to answer your question, YES and NO, depending on > SWR on the coax between the tuner output and the loop antenna feed point. > > In general, R-8X is OK at 500 watts below 30 MHz. From experience, it > will get "warm" to the touch. "Warm" is created by loss which is then > heat generated from RF. And that is RF which is not getting to the > antenna. > > Personally I'd opt for a balanced open wire feed to the loop and a very > good 1:1 balun rated for legal limit or more at the KAT500 tuner output. > > 73 > > Bob, K4TAX > > >> On 8/20/2019 2:11 PM, Carter Craigie wrote: >> Hello friends, >> >> I am contemplating buying a KPA500 amplifier/tuner Combo, and driving it >> from my Elecraft K2/100 rig. I hope I would be able to do that! >> >> From what I have read on eHam Reviews, it appears that I can run the >> amp/tuner combo on 117v. from the convenient wall socket. Is that correct, >> as well? >> >> I cannot find any mention of the coax requirements, from the radio/combo >> out to our 80-meter wire loop antenna. Right now, using only my K2/100 I am >> able to use 8X coax. >> >> Will I still be able to use that coax cable with up to 500 Watts output? >> >> What other considerations do I need to make? >> >> Thanks in advance, >> >> Carter Craigie, N3AO >> Blacksburg, VA >> >> > > ______________________________________________________________ > 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 > Message delivered to [email protected] > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
