I had the same problem with my KPA1500. The exciter was an Icom 7610. I my case I saw it on other bands to but it was more intermittent. After some troubleshooting I concluded the trouble to be in the negative feedback loop in the PA. I talked with the tech at Elecraft, he agreed and he sent me a pic with some spots highlighted to look for poor solder joints. One did look suspicious so I reflowed it. Since then it hasn't happened but I don't think reflowing that joint really fixed it.
Now that you have seen the same thing I'm more suspicious of a defective component. Probably a bad cap in the feedback loop. I suggest you call Elecraft and ask to talk to Rene Morris about it. 73, Dale AA1QD -----Original Message----- From: Steve Masticola [mailto:steve.mastic...@verizon.net] Sent: Wednesday, April 06, 2022 2:56 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA1500 gain jumping on 160 Has anyone else seen the kind of gain jumping on 160 shown here? https://www.youtube.com/watch?v=LjfksHwLz9w The exciter is a K3, and I generated the drive signal by putting it into TUNE mode. The KPA1500 is feeding directly into a dummy load, so the antenna, etc. is not the cause. I believe I heard about a "160 gain reduction mod" to correct this problem, but I can't recall where I saw it. 73, -Steve WX2S ______________________________________________________________ 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
