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41. [AMPS] Purpose of CW/SSB switch (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Fri, 11 Sep 1998 09:59:58 -0600; Hello Phil, ALPHA amps built before the FCC power limit was changed (about 1977-78) were designed for convenient "1 kW dc INPUT". That old rule, in effect since the CW & AM 30's, was ambiguous and ab; /archives//html/Amps/1998-09/msg00135.html (11,139 bytes)
42. [AMPS] Purpose of CW/SSB switch (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 14 Sep 1998 10:46:43 -0600; Hello John, The switch was traditional in our amps for the purposes I mentioned earlier, and we included it in the 87A mostly with the expectation that some guys would still want it for lower-power u; /archives//html/Amps/1998-09/msg00188.html (9,600 bytes)
43. [AMPS] Purpose of CW/SSB switch (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 14 Sep 1998 10:46:59 -0600; Hi Matt... The primary reason for providing the LO tap on earlier models was to allow safe and efficient CW operation at 1 kW dc input, the FCC limit pre-19'77. It's generally fine to run the older A; /archives//html/Amps/1998-09/msg00189.html (10,786 bytes)
44. [AMPS] 3CV1500A7 (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 3 Aug 1998 15:00:33 -0600; Greetings Paul... To the best of my recollection, Eimac decided to discontinue making the 3CV1500A7 (actually a 3CX1000A7 with a boiler instead of air fins) some time in the late 70's. ETO had alread; /archives//html/Amps/1998-08/msg00017.html (8,572 bytes)
45. [AMPS] 3CV1500A7; what is vapor cooling? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 4 Aug 1998 14:14:15 -0600; Hi Jon & all... Concerning your question, Jon, the best readily-available explanation of vapor-phase cooling that I know of was a construction article by Jack Quinn (of Eimac) in QST around 1968 give; /archives//html/Amps/1998-08/msg00030.html (11,522 bytes)
46. [AMPS] Properties of plastics at 10 GHz (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Thu, 20 Aug 1998 21:18:06 -0600; Delrin is an EXCELLENT dielectric throughout the hf range, but its melting temp is fairly low - somewhere in the vicinity of 100 C I'd guess. So of course it will melt if nearby current-carrying cond; /archives//html/Amps/1998-08/msg00175.html (10,325 bytes)
47. FW: [AMPS] hot switching (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Fri, 21 Aug 1998 10:08:11 -0600; Hi Dave & all... Relative to the T/R circuit you're asking about, I don't have Dick Frey's article or any of the older handbooks where I can put my hand on 'em, but I believe the technique he describ; /archives//html/Amps/1998-08/msg00180.html (11,175 bytes)
48. [AMPS] Ten Tec Corsair QSK and the 87A (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 26 Aug 1998 21:18:24 -0600; Hello Jim... ALPHA 87A's (and also 89's and 91B's) T/R response time typically is 1-2 msec. Using any popular Japanese transceiver that I'm familiar with (FT-1000D, TS-950SD & SDX, TS-850, IC-761 & 7; /archives//html/Amps/1998-08/msg00219.html (11,125 bytes)
49. [AMPS] Cathode input networks resonant or not? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Fri, 28 Aug 1998 21:36:17 -0600; I submit - admittedly without PhD-level academic documentation but based on hands-on experience - that if the cathode network isn't resonant at or fairly near the operating frequency there's no "flyw; /archives//html/Amps/1998-08/msg00242.html (9,279 bytes)
50. [AMPS] Cathode input networks resonant or not? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Sun, 30 Aug 1998 14:05:11 -0600; on FAIRLY NEAR the operating frequency there's no "flywheel." Presumably you "hands-on" MEASURED the resonant frequency with the amp turned OFF, or at least with tubes biased to cutoff. In either cas; /archives//html/Amps/1998-08/msg00249.html (8,613 bytes)
51. [AMPS] Why class B?? (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 8 Jul 1998 14:30:28 -0600; Hi Ian... Just got back from Friedrichshafen & tooling around E. & W. Europe for a few extra days and am catching up on mail at ETO. Of course I agree emphatically that class of amplifier operation (; /archives//html/Amps/1998-07/msg00049.html (10,257 bytes)
52. [AMPS] Vacuum Cap Rating and Plate Voltage (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 21 Jul 1998 11:06:36 -0600; As anyone who's ever [FOOLISHLY -- DON'T TRY THIS AT HOME!] used a pencil to draw a fiery inch-long arc from the cap of anything bigger than an 813 can attest! Dick __________________________________; /archives//html/Amps/1998-07/msg00121.html (8,805 bytes)
53. [AMPS] RE: Pencils and fiery inch-long arcs! (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 22 Jul 1998 11:00:09 -0600; Hi Bob... I agree completely and absolutely! It's a wonder that any of us post-WW II teen-age amplifier home brewers survived our ignorance and foolishness. I got knocked against the wall once while; /archives//html/Amps/1998-07/msg00136.html (13,728 bytes)
54. [AMPS] RE: Pencils and fiery inch-long arcs! (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 22 Jul 1998 12:00:22 -0600; VERY GOOD POINT, Pete! I should have mentioned that - always keep the blade of the screwdriver solidly grounded to chassis BEFORE AND WHILE touching it to the HV line. The safety advantage of a prope; /archives//html/Amps/1998-07/msg00140.html (9,487 bytes)
55. [AMPS] Re: SSB Power Output and the value (?) of 1.5 dB (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Fri, 24 Jul 1998 12:33:22 -0600; Hi Jon, Tom, Pete, Denny & all... Agreed, if a signal is fairly in the clear and strong enough to even tickle an S-meter, another 1.5 dB probably won't make much difference in readability. OTOH, unde; /archives//html/Amps/1998-07/msg00177.html (9,160 bytes)
56. [AMPS] 3CX800 (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 28 Jul 1998 20:59:40 -0600; Hi Steve and all... It's my understanding that an "electron cloud" forms around the cathode whenever the current drawn from it is less than its emissive capability. This negatively-charged cloud effe; /archives//html/Amps/1998-07/msg00196.html (8,929 bytes)
57. [AMPS] EIMAC 8874 tubes (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 28 Jul 1998 21:28:13 -0600; Hello Dean... A loud "bang" generally means that something has exploded in the HV area. An arc inside the vacuum envelope of a tube makes little or no audible noise itself. But the resultant HV curre; /archives//html/Amps/1998-07/msg00197.html (10,865 bytes)
58. FW: [AMPS] MLA-2500 Help (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Wed, 29 Jul 1998 09:58:26 -0600; Hi Bob... One OPEN cap in the HV cap string definitely WILL reduce no-load HV - from ~1.41 x rms AC voltage (the peak value which a capacitance filter will hold to under no-load conditions) to roughl; /archives//html/Amps/1998-07/msg00202.html (9,717 bytes)
59. [AMPS] No 24 MHz (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Mon, 1 Jun 1998 10:42:45 -0600; Hi Alek... If your plate choke were absorbing even 100W I believe it would quickly become hot enough to smoke. Another possibility - maybe - a choke impedance consisting of a low value of effective s; /archives//html/Amps/1998-06/msg00010.html (9,890 bytes)
60. [AMPS] Solid State 1kw amp (score: 1): Author: w4eto@rmii.com (Richard W. Ehrhorn); Date: Tue, 2 Jun 1998 15:12:47 -0600; Hi Dave... ...snip... > of interest is possibly a broadband tube amp design requiring no tuning on the HF ham bands, any input is appreciated. Thousands of ALPHA 374, 374A and 78 amps (up to 24 years; /archives//html/Amps/1998-06/msg00043.html (8,605 bytes)

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