[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
Re: [Elecraft] KPA1500 gain jumping on 160
Steve, A good start would be to redo the K3 TX GAIN CALIBRATION. Do not use the Utility, do it manually. This problem can occur as a result of varying drive from the K3, typically from previously transmitting at either 5 or 50 watts. Using your dummy load, set the K3 PWR to 5w. In CONFIG: TUN PWR set the value to 5 watts. Then hold TUNE on the K3 to see a display of 5w. Tap TUNE. Repeat the procedure at 50w. Reset CONFIG: TUN PWR to any value EXCEPT 5 or 50w. With the KPA1500 in OPER set the PWR control on the K3 to your usual drive level. Hopefully this will fix the problem. 73, Jim W6YA __ 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
Re: [Elecraft] KPA1500 gain jumping on 160
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
