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21. [AMPS] isolation question (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 16 Feb 1999 12:10:15 -0700; In real life the actual rf breakdown voltage of a capacitor commonly is determined by unintended/unrecognized/unknown regions of unexpectedly high voltage GRADIENT - often many times higher volts per; /archives//html/Amps/1999-02/msg00427.html (11,220 bytes)
22. [AMPS] Cure for "Monitor Ripple" from Amp's PS ? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 16 Feb 1999 12:27:17 -0700; Hi Billy... It's common for the 50-60 Hz field of a transceiver or amp power transformer to cause ripple and distortion on a magnetically-unshielded CRT nearby. . Severity depends on multiple factors; /archives//html/Amps/1999-02/msg00428.html (9,693 bytes)
23. [AMPS] isolation question (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 17 Feb 1999 15:45:15 -0700; Hi Carl... It's only a gut feeling, but I'd prefer a single thicker piece of Teflon to multiple thin ones, because the latter creates more interstices (!?!) between layers - where air can lie in wait; /archives//html/Amps/1999-02/msg00457.html (12,203 bytes)
24. [AMPS] isolation question (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Thu, 18 Feb 1999 21:20:27 -0700; Hi Carl... All your points are well taken - particularly the first one: I really don't know whether monolithic or multi-layered is best; it likely depends on specific parameters of the application in; /archives//html/Amps/1999-02/msg00489.html (7,881 bytes)
25. FW: [AMPS] (no subject) (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Fri, 4 Dec 1998 14:29:46 -0700; Hi Bill... Enjoyed reading you posting (below) - naturally! But with all due respect, even ALPHAs aren't "TOTALLY" idiot-proof. The reason is - and please understand that the following absolutely is; /archives//html/Amps/1998-12/msg00055.html (10,799 bytes)
26. FW: [AMPS] Alpha 77SX Tone (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 15 Dec 1998 11:41:38 -0700; Hi Ivo... It's difficult to imagine any way in which an amplifier can directly introduce "chirp," which is frequency variation, onto the signal. My guess would be that mains voltage changes enough wh; /archives//html/Amps/1998-12/msg00235.html (7,829 bytes)
27. [AMPS] Alpha 78 problem (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Sat, 10 Oct 1998 12:01:30 -0600; If I remember right there should be 10 ohms/25W on each side of the 240V line input. 73, Dick There's a wirewound resistor in front of the xfrmr. Actually there are three of them. THey can open when; /archives//html/Amps/1998-10/msg00091.html (8,459 bytes)
28. [AMPS] My old amp (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 13 Oct 1998 18:02:36 -0600; Unless I'm mistaken the original Loudenboomer came from Lee Bergren's (W0AR?) Radio Industries in Kansas City. Think Hunter built the Bandit in or near Iowa City - in Collins country. Definitely a ha; /archives//html/Amps/1998-10/msg00175.html (10,355 bytes)
29. [AMPS] bulbs for alpha 78 (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Thu, 15 Oct 1998 11:46:20 -0600; Tom, I'd certainly check with Scott, Steve or Glenn at Alpha/Power, Inc. first. Phone (970) 535-4173. 73, Dick W0ID/ex-W4ETO I have a meter light bulb out in my alpha 78. It is the green color bulb t; /archives//html/Amps/1998-10/msg00196.html (7,506 bytes)
30. [AMPS] 8877 Idling Current?? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Thu, 15 Oct 1998 12:02:46 -0600; Hi Gary... I'd say anywhere from 100-160 mA is typical, but of course meter accuracy (nominal +/- 5k% of FULL SCALE) isn't great at the very low scale edge. Generally the idling current of the 3CX800; /archives//html/Amps/1998-10/msg00278.html (8,162 bytes)
31. FW: [AMPS] Alpha 76PA repairs-rf choke & plate tank damage (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 19 Oct 1998 09:48:46 -0600; Hi guys... The by-far-most-likely cause of a toasted plate choke in a 76A/CA/PA-374A-78 or earlier series ALPHA is attempting to operate it on 25-27 MHz without modification. We intentionally placed; /archives//html/Amps/1998-10/msg00284.html (10,576 bytes)
32. [AMPS] Alpha 89 (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 19 Oct 1998 10:00:51 -0600; Hi Henry... If a power tube is otherwise "perfect," ultimate useful lifetime probably will be determined by total heater-on time. OTOH, a high number of heater/filament power on/off cycles clearly co; /archives//html/Amps/1998-10/msg00285.html (8,171 bytes)
33. [AMPS] Re: ETO/Alpha 12M mods (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 26 Oct 1998 16:10:57 -0700; Hi guys... FYI, at ETO/ALPHA we did come up maybe 7 or 8 years ago (?) with a solution to the 12M enablement of legacy ALPHAs. The only one that we were sufficiently satisfied with to offer as a fact; /archives//html/Amps/1998-10/msg00398.html (10,526 bytes)
34. [AMPS] Minimizing circulating currents on 10M. (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 26 Oct 1998 16:11:58 -0700; More precisely, you need to keep the LOADED 'Q' relatively low - preferably not much over 10. This in turn requires keeping total input capacitance of the pi network low, which may not be possible wh; /archives//html/Amps/1998-10/msg00399.html (10,108 bytes)
35. [AMPS] Alpha repair (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 26 Oct 1998 16:12:20 -0700; Hi Natan... Of course I'm biased (so to speak), but I'd urge you to contact Carl, John or maybe Glenn at Alpha/Power as a start. It costs mighty little to call, and these are the guys that know the c; /archives//html/Amps/1998-10/msg00400.html (7,717 bytes)
36. FW: [AMPS] Re: ETO/Alpha 12M mods (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 28 Oct 1998 08:59:38 -0700; Absolutely correct, Pete. 73 & good DXing. Dick W0ID I have been following this thread quite closely, and my thanks to all contributors, public and private. Am I correct in concluding the 76CA (3 hol; /archives//html/Amps/1998-10/msg00428.html (8,425 bytes)
37. [AMPS] High IMD Drivers (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 1 Sep 1998 11:27:30 -0600; Craig, I have spent many hours playing with these. I used to design them! Most of the current "linear" amplifiers used in digital cellular service use feed-forward amplifiers. It's an amazing techniq; /archives//html/Amps/1998-09/msg00012.html (15,564 bytes)
38. [AMPS] output on pair 3xc800a7's (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 2 Sep 1998 08:54:14 -0600; Hi Tom... 1. The main differences between a standard (unmodified) ALPHA 78 and a 374A are (a) 78 has three 8874 tubes while 374A has two, and (b) the 78 has full break-in/QSK using a vacuum T/R relay; /archives//html/Amps/1998-09/msg00029.html (11,940 bytes)
39. [AMPS] high IMD drivers (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 2 Sep 1998 09:16:01 -0600; Hello Peter... I don't have a set of FCC rules here at home, but my recollection is that (in fairly typical FCC fashion) there is no explicit "dB" IMD requirement, at least for amps. Think rules say; /archives//html/Amps/1998-09/msg00030.html (9,576 bytes)
40. [AMPS] FW: Buying Guidelines for Used 8877/3CX1500A7's (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 2 Sep 1998 12:56:39 -0600; Hi David... Think below is what you're looking for ... 73, Dick Hi again Terry, .Just in case, the actual time period to look out for begins approximately August 1986 (date code roughly 8630?) when E; /archives//html/Amps/1998-09/msg00033.html (8,551 bytes)

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