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81. Re: [Amps] Switching Power Supplies (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 14 Jul 2006 17:29:28 -0400; The filament transformer is typically about 5-10% of overall amplifier weight. On a 60 pound amp that's 3-6 pounds. If the switching supply cuts that in half, we save 1-1/2 to 3 pounds. I think the; /archives//html/Amps/2006-07/msg00397.html (9,118 bytes)
82. Re: [Amps] Switching Power Supplies (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 14 Jul 2006 18:51:44 -0400; How will a switching supply handle a HV to ground fault if the tube arcs? 73 Tom _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mai; /archives//html/Amps/2006-07/msg00398.html (9,145 bytes)
83. Re: [Amps] Switching Power Supplies (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 14 Jul 2006 21:48:54 -0400; 17% no load to full load regulation isn't so hot Joe. I'm not sure how that would be for IM products or CW waveform since power out is generally about the square of supply voltage change. The CW wav; /archives//html/Amps/2006-07/msg00404.html (9,668 bytes)
84. Re: [Amps] Switching Power Supplies (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 14 Jul 2006 21:53:48 -0400; The cool down time is about the same as the warm up time Ian, momentary sags wouldn't hurt a thing. Personally, I'd use a constant voltage transformer if it was that big of a deal. If I used a switc; /archives//html/Amps/2006-07/msg00405.html (8,862 bytes)
85. [Amps] Transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sat, 15 Jul 2006 00:01:33 -0400; The SB220 transformer was designed for a kilowatt INPUT DC, which was the legal input when it was designed. This was about 450 mA at about 2200 volts. It was a good conservative design for that powe; /archives//html/Amps/2006-07/msg00408.html (10,603 bytes)
86. Re: [Amps] Transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sat, 15 Jul 2006 06:45:08 -0400; Manuals are written from other manuals, and the goal was to always be conservative. Manual writers at Heath were a completely different group than engineers. I don't think I talked to a manual write; /archives//html/Amps/2006-07/msg00417.html (11,010 bytes)
87. Re: [Amps] Transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 16 Jul 2006 07:15:44 -0400; Perhaps I just didn't understand what you are trying to say Will, but you finally added core cross-section to the equation. I think I understand what you are trying to say. I just wanted to be sure; /archives//html/Amps/2006-07/msg00437.html (10,923 bytes)
88. Re: [Amps] Transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 16 Jul 2006 07:23:12 -0400; Just to be clear, no one is suggesting otherwise. But a 10kVA transformer design does NOT come up to kVA and then start limiting. Much of the previous wording in this thread seemed to imply flux den; /archives//html/Amps/2006-07/msg00438.html (7,783 bytes)
89. Re: [Amps] transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 16 Jul 2006 13:48:31 -0400; Because the SB200 was not rated at a kilowatt input power, as measured on the meters, on SSB. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.conte; /archives//html/Amps/2006-07/msg00451.html (8,221 bytes)
90. [Amps] SB220 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 16 Jul 2006 18:07:04 -0400; Roy, The law was 1 kW DC input with suitable metering. That specification included a dampening or response factor in the meters, and to run a full KW you had to be able to read HV and Ip at the same; /archives//html/Amps/2006-07/msg00455.html (11,055 bytes)
91. Re: [Amps] transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 16 Jul 2006 21:43:09 -0400; I've never seen a pair of 3-500Z's driven with 100 watts produce 1500W PEP **on an accurate power meter** with only 3000V on the anode. Neither did B&W. Neither did Viewstar. That's why they ran 350; /archives//html/Amps/2006-07/msg00471.html (9,566 bytes)
92. Re: [Amps] transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 06:00:31 -0400; One thing I have learned doing RF measurements almost every day for 30 years or more is RF measurements are tougher to do than most imagine. The accuracy of a Bird 43 meter, when properly calibrated; /archives//html/Amps/2006-07/msg00486.html (9,645 bytes)
93. Re: [Amps] transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 06:15:32 -0400; I haven't seen the meter. I do know several years ago I pushed them to buy a high accuracy Bird meter and matched slugs. I would certainly never guess at the absolute accuracy of anything leaving an; /archives//html/Amps/2006-07/msg00488.html (10,139 bytes)
94. Re: [Amps] transformers (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 06:19:13 -0400; Be sure you read the reflected power on a suitable slug. I have very few things, other than commercial loads, that are !:1 SWR. I even have a tough time finding 50 ohm coax that is really exactly 50; /archives//html/Amps/2006-07/msg00489.html (9,043 bytes)
95. Re: [Amps] RF Chokes (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 10:14:52 -0400; If we remember what a "series resonance" really is, where the choke looks like a back-to-back L network group or groups with extremely high L and very low C, it's easy to understand what will or wil; /archives//html/Amps/2006-07/msg00514.html (8,692 bytes)
96. [Amps] QRO membership revoked (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 10:45:11 -0400; I just spent four days of transmitting with less than 26 watts. This is the longest accumulated time I've spent since 1962 or 63 at such a disgusting power level. I have a hollow gnawing feeling in m; /archives//html/Amps/2006-07/msg00519.html (6,856 bytes)
97. [Amps] Power PEP vs drive power (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 13:49:26 -0400; Actually drive power is fully accounted for on the front panel meters except for the contribution to voltage it causes, so the "deduct drive power" is just as bad the other way as not doing anything; /archives//html/Amps/2006-07/msg00534.html (9,838 bytes)
98. Re: [Amps] output of SB220 typical TSPA (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 17 Jul 2006 19:19:12 -0400; Jim, A single tube will easily make 1200 watts or more with enough drive at 3000 volts, and you don't have to run the filament extra hot to do it. There isn't any doubt at all people are seeing 2kW; /archives//html/Amps/2006-07/msg00549.html (8,048 bytes)
99. [Amps] Life and gain of 3-500Z (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 18 Jul 2006 06:14:21 -0400; The filament life issue is primarily an issue with good manufacturing quality and steady operation at conservative values. Say you run a tube 24/7/52. In a week you have 168 hours. In a year 8736 ho; /archives//html/Amps/2006-07/msg00558.html (9,465 bytes)
100. Re: [Amps] RF Chokes (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 18 Jul 2006 06:15:45 -0400; I've always asked myself how could be rated for no resonances (in any amateur band) if the thing depends of the surrounding objects?.>>> It can't possibly be rated that way. 73 Tom __________________; /archives//html/Amps/2006-07/msg00559.html (8,042 bytes)

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