He said that his SWR on 12m was already low, so I don't see how that helps a lot.
Dave AB7E On 1/8/2013 6:40 PM, Rick Bates wrote:
Try altering your feedline length (which means resetting the KAT500 memories too). I had a similar issue on 80M. However in my case, it made no difference when I added 30' more window line but changing the coax length (+~30') allowed it to load. The doublet length is 170' per side (all HOA stealthy too). I use a 10 KW rated DX Engineering 1:1 common mode choke to convert window line to coax AND keep RF outside the shack. Their website has a 'white paper' comparing 1:1 and 4:1 which is worth reading too. 73, Rick wa6nhc -----Original Message----- From: Ron W3ZV At least I'm pretty sure its an RFI problem. I have a K3, KAT500 and the KPA500 connected as recommended with Elecraft DB15HD cables. The antenna is a 120ft. doublet fed with ladder line to a 4:1 balun and 10ft of coax to the KAT500. I have a comment point ground to a ground rod six foot from the shack. I have operated the amp at 400+ watts from 80m to 6m. The only band that gives me a problem is 12m. When I am operating at 400 watts ssb, the amp will fault with a high swr indication within 5 to 20 seconds. Immediately prior to the fault the swr on the amp display was 1.2:1. Reducing power to below 300 watts seems to avoid the problem. Assuming the consensus is that this is RFI, what would be the most likely suspect? Coax cables in/out? DB15HD cable? Power cable? What's the easiest way to diagnose and correct the problem? Thanks Ron W3ZV ______________________________________________________________ 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
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