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Total 14 documents matching your query.

1. [Amps] rx noise? (score: 1): Author: "K1TTT" <K1TTT@ARRL.NET>; Date: Sat, 06 Dec 2008 15:11:58 +0000; I have a commander hf-2500 (pair of 3cx800a7's, no qsk) that seems to be working fine. However, during cqww cw last week I had to pull it off the 20m station because it was making a broadband noise w; /archives//html/Amps/2008-12/msg00119.html (7,187 bytes)
2. Re: [Amps] rx noise? (score: 1): Author: n8de@thepoint.net; Date: Sat, 06 Dec 2008 12:24:57 -0500; Dave, Sounds like a leaky power supply capacitor. Might be a cold solder joint in the capacitor chain. Good luck Don N8DE _______________________________________________ Amps mailing list Amps@contes; /archives//html/Amps/2008-12/msg00121.html (8,529 bytes)
3. Re: [Amps] rx noise? (score: 1): Author: "Tim Duffy K3LR" <k3lr@k3lr.com>; Date: Sat, 6 Dec 2008 11:28:44 -0600; Hi Dave, I don't know the relay(s) used in the HF-2500, but I wonder if this problem is one of the RX/TX relays in the amp (either input or output side contacts) that is starting to go bad? Sort of l; /archives//html/Amps/2008-12/msg00122.html (8,637 bytes)
4. Re: [Amps] rx noise? (score: 1): Author: DAVE WHITE <mausoptik@btinternet.com>; Date: Sat, 6 Dec 2008 17:51:32 +0000 (GMT); That was going to be my suggestion if the HT is dropping a bit more than you'd expect. I had the same sort of thing without the HT drop when a painted but not earthed oil filled capacitor started lea; /archives//html/Amps/2008-12/msg00124.html (10,136 bytes)
5. Re: [Amps] rx noise? (score: 1): Author: "Paul Kraemer" <elespe@lisco.com>; Date: Sat, 6 Dec 2008 11:56:37 -0600; How about from a zener diode in a bias supply. They make dandy noise generators and were the source of widband rf for the old Omega noise bridge. The current to make noise is critical, line voltage u; /archives//html/Amps/2008-12/msg00125.html (9,576 bytes)
6. Re: [Amps] rx noise? (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sat, 6 Dec 2008 13:53:37 -0500; Check the bias switch (relay, transistor, ?). If cutoff is not being applied in receive, the tube will generate wideband noise ("shot" noise). 73, ... Joe, W4TV ______________________________________; /archives//html/Amps/2008-12/msg00126.html (10,909 bytes)
7. Re: [Amps] rx noise? (score: 1): Author: "David Robbins K1TTT" <k1ttt@arrl.net>; Date: Sat, 06 Dec 2008 23:46:56 +0000; I really, REALLY hate intermittent problems like this... it wouldn't do it cold. So I started warming it up, after 1/2 hour or so I got the transformer up to 225f, the rf deck surface about 150f, the; /archives//html/Amps/2008-12/msg00128.html (13,036 bytes)
8. Re: [Amps] rx noise? (score: 1): Author: "k7fm" <k7fm@teleport.com>; Date: Sat, 6 Dec 2008 19:12:31 -0800; The 15 seconds of receiver noise during a contest is normal. It is the ghost of Hiram Percy Maxim firing up the retary spark gap on 160 meters. You may not be able to recreate it until the next conte; /archives//html/Amps/2008-12/msg00132.html (7,782 bytes)
9. Re: [Amps] rx noise? (score: 1): Author: "W7RY" <w7ry@arrl.net>; Date: Sat, 6 Dec 2008 21:25:41 -0800; I would suspect the HV diodes rather than the filter caps. You did say there was plate voltage fluctuations? 73 Jim W7RY I really, REALLY hate intermittent problems like this... it wouldn't do it col; /archives//html/Amps/2008-12/msg00133.html (13,162 bytes)
10. Re: [Amps] rx noise? (score: 1): Author: "David Robbins K1TTT" <k1ttt@arrl.net>; Date: Sun, 07 Dec 2008 12:00:31 +0000; Some cold snowy morning, like this morning, I may sit down and hold a rtty contest with it to try some more. I'll likely check some of the switching circuit today and make sure the bypass caps are i; /archives//html/Amps/2008-12/msg00137.html (9,381 bytes)
11. Re: [Amps] rx noise? (score: 1): Author: "David Robbins K1TTT" <k1ttt@arrl.net>; Date: Sun, 07 Dec 2008 12:06:53 +0000; The plate voltage fluctuations are from line sag from another amp running the 160m contest. I couldn't sort that out last week with the m/m operation, but yesterday's test showed that the noise occur; /archives//html/Amps/2008-12/msg00138.html (16,777 bytes)
12. Re: [Amps] rx noise? (score: 1): Author: "Jim Brown" <jim@audiosystemsgroup.com>; Date: Sun, 07 Dec 2008 15:43:50 -0800; A T/R relay going south seems like a possibility. I'd give it a go calling CQ on 80 or 160 during the day with full QSK. If it's a relay, that ought to make it stop being intermittent. A common failu; /archives//html/Amps/2008-12/msg00155.html (8,108 bytes)
13. Re: [Amps] rx noise? (score: 1): Author: "David J Windisch" <davidjw@cinci.rr.com>; Date: Sun, 7 Dec 2008 19:38:14 -0500; Iirc, the design didn't have bypassing on 78XX regulators, which can oscillate. 10uF//0.1uF in and out may tame this beast. One of the locals had this problem in a 6M version. 73 Dave W8FGX _________; /archives//html/Amps/2008-12/msg00157.html (8,134 bytes)
14. Re: [Amps] rx noise? (score: 1): Author: "GARY SWARTOUT" <k7gs@msn.com>; Date: Sun, 7 Dec 2008 11:13:20 -0800; I had a similar noise problem from my amp that was caused by a loose plate cap. The fan vibration was enough to cause the amp to act as an oscillator. Try tuning the plate cap when you have the noise; /archives//html/Amps/2008-12/msg00162.html (17,209 bytes)

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