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Total 15 documents matching your query.

1. [Amps] 300Hz sidebands (score: 1): Author: Conrad PA5Y <g0ruz@g0ruz.com>; Date: Sun, 23 May 2021 16:35:57 +0000; Hi all. I have several tetrode amplifiers that run from a 3PH 50Hz supply. With the advent of the FT8 I have become aware that I have 300Hz sidebands at only -50dBc, this is obviously unacceptable. T; /archives//html/Amps/2021-05/msg00047.html (7,324 bytes)
2. Re: [Amps] 300Hz sidebands (score: 1): Author: "sm0aom@telia.com" <sm0aom@telia.com>; Date: Sun, 23 May 2021 19:53:22 +0200 (CEST); I would suggest checking both the choke and the capacitor, If there has been a short in the overvoltage protector across the choke, it would be out of the circuit. Without the choke, the ripple incre; /archives//html/Amps/2021-05/msg00048.html (9,518 bytes)
3. Re: [Amps] 300Hz sidebands (score: 1): Author: Jim <jimw7ry@gmail.com>; Date: Sun, 23 May 2021 13:02:50 -0500; Reported by whom? What did they use to measure it? Did you get a second opinion? Is it your exciter? Are you over driving your radio from the computer? Since you run 1KW on FT8, have you been put on; /archives//html/Amps/2021-05/msg00049.html (9,073 bytes)
4. Re: [Amps] 300Hz sidebands (score: 1): Author: Conrad PA5Y <g0ruz@g0ruz.com>; Date: Sun, 23 May 2021 18:13:49 +0000; Well of course initially I poured scorn on the complainers. But I have an E4406B spectrum analyser. So, I got a second opinion from myself. Sadly, they were right +/- 300Hz @ -50dBc. On VHF we can ru; /archives//html/Amps/2021-05/msg00050.html (10,166 bytes)
5. Re: [Amps] 300Hz sidebands (score: 1): Author: "sm0aom@telia.com" <sm0aom@telia.com>; Date: Sun, 23 May 2021 20:51:52 +0200 (CEST); On the schematic a choke, Dr 401, is shown between the six-pulse bridge and the filter capacitor. It is bridged by an overvoltage protector. As you do not generate the screen voltage from the plate s; /archives//html/Amps/2021-05/msg00051.html (11,055 bytes)
6. Re: [Amps] 300Hz sidebands (score: 1): Author: Geert Jan de Groot <pe1hzg@xs4all.nl>; Date: Mon, 24 May 2021 19:52:44 +0200; Apologies for asking, but have you tried a different driver transceiver to see if the signal (level and/or frequency) changes? Geert Jan _______________________________________________ Amps mailing l; /archives//html/Amps/2021-05/msg00054.html (7,602 bytes)
7. Re: [Amps] 300Hz sidebands (score: 1): Author: Conrad PA5Y <g0ruz@g0ruz.com>; Date: Mon, 24 May 2021 18:09:28 +0000; Hello Geert. Yes, I did try 3 different drivers, and several amplifiers off this HT supply. The same result. TS2000 IC746 Same result. I eventually got the supply out of the rack and took the lid off; /archives//html/Amps/2021-05/msg00055.html (8,710 bytes)
8. Re: [Amps] 300Hz sidebands (score: 1): Author: Jim <jimw7ry@gmail.com>; Date: Tue, 25 May 2021 20:25:34 -0500; What about a different amplifier power supply. What about a different supply (or battery) for the exciter? Thanks 73 Jim W7RY Yes, I did try 3 different drivers, and several amplifiers off this HT su; /archives//html/Amps/2021-05/msg00056.html (9,638 bytes)
9. Re: [Amps] 300Hz sidebands (score: 1): Author: Conrad PA5Y <g0ruz@g0ruz.com>; Date: Wed, 26 May 2021 08:31:58 +0000; Hello Jim, the previous owner removed the HT choke! These sidebands are as expected for a 3PH 6 pulse capacitor smoothed supply. The original choke is on its way here which will improve things by 20d; /archives//html/Amps/2021-05/msg00060.html (11,156 bytes)
10. Re: [Amps] 300Hz sidebands (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Wed, 26 May 2021 02:15:22 -0700; Conrad, As an engineer, I LOVE your proper sense of perspective. Here in the former colonies, I often see splatter 0n 40M, most of it produced by Yeasu rigs, that extends 2-3 kHz on both sides of the; /archives//html/Amps/2021-05/msg00061.html (9,740 bytes)
11. Re: [Amps] 300Hz sidebands (score: 1): Author: "sm0aom@telia.com" <sm0aom@telia.com>; Date: Wed, 26 May 2021 13:02:22 +0200 (CEST); Yes, a sense of perspective and proportions always helps. A lot of current amateur gear show quite atrocious adjacent channel performance, especially in the hands of the "all knobs to the right" crow; /archives//html/Amps/2021-05/msg00062.html (11,352 bytes)
12. [Amps] 300Hz sidebands (score: 1): Author: "jim.thom jim.thom@telus.net" <jim.thom@telus.net>; Date: Wed, 26 May 2021 07:25:28 -0700; On the schematic a choke, Dr 401, is shown between the six-pulse bridge and the filter capacitor. It is bridged by an overvoltage protector. As you do not generate the screen voltage from the plate s; /archives//html/Amps/2021-05/msg00063.html (9,567 bytes)
13. Re: [Amps] 300Hz sidebands (score: 1): Author: Conrad PA5Y <g0ruz@g0ruz.com>; Date: Wed, 26 May 2021 16:39:11 +0000; Hello Jim, it is a grid driven tetrode in AB1, the G2 supply is shunt stabilised and from a separate single-phase transformer. I can assure you that the drive level and therefore the anode current do; /archives//html/Amps/2021-05/msg00064.html (10,658 bytes)
14. Re: [Amps] 300Hz sidebands (score: 1): Author: "Gary Schafer" <garyschafer@largeriver.net>; Date: Wed, 26 May 2021 20:18:29 -0500; "Ripple modulation factor" has to do with the inability of a tetrode AB1 amplifier to be plate modulated by changing plate voltage. This goes along with the fact that changing the plate voltage has v; /archives//html/Amps/2021-05/msg00065.html (12,481 bytes)
15. Re: [Amps] 300Hz sidebands (score: 1): Author: Finn Hoffmann via Amps <amps@contesting.com>; Date: Fri, 28 May 2021 15:07:15 +0200; Hello Conrad, It is not that difficult to find out, what is happening. If you have 4% 300Hz ripple, a clas C amplifier will be platemodulated with 4% 300Hz modulation. If the amplifier is class A, th; /archives//html/Amps/2021-05/msg00066.html (12,347 bytes)

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