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181. [Amps] reducing the reactance of a wirewound resistor (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 05 Feb 2012 01:30:51 -0700; Do you mean Aryton-Perry winding? Check it on google. John K5PRO _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amp; /archives//html/Amps/2012-02/msg00007.html (8,996 bytes)
182. Re: [Amps] HV feedthrough capacitor (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Fri, 10 Feb 2012 13:49:23 -0700; The German company Draloric makes some great ceramic HV feedthroughs and bypass caps. For lower frequencies, they have a high K dielectric that yields large capacitances. These parts will work into t; /archives//html/Amps/2012-02/msg00093.html (7,042 bytes)
183. [Amps] HV Feed Through Capacitor for UHF Amplifier (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Mon, 13 Feb 2012 00:29:10 -0700; A reply follows, I apologize for the length. I have worked on this problem a lot over the years and its a tricky one to solve at high power coincident with high frequencies: shown on the ND2X web sit; /archives//html/Amps/2012-02/msg00121.html (11,875 bytes)
184. [Amps] Bleeders (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 29 Feb 2012 18:19:48 -0700; For the big power supply for my TH628 amplifier, 28 kV with 225 uF, do not use a high power bleeder. It is a pulsed amplifier, so we need all the current we can get, during each mS long pulse. There; /archives//html/Amps/2012-02/msg00344.html (8,483 bytes)
185. [Amps] 432 Cavity Amps; Thomson TH 331 (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Thu, 1 Mar 2012 15:02:19 -0700; Not likely to find an exact replacement in the USA, as Burle/RCA and Eimac were the only mainland producers of UHF tetrodes like that, and they have reduced production to near nothingness, as the mar; /archives//html/Amps/2012-03/msg00014.html (10,264 bytes)
186. [Amps] 432 Cavity Amps; Thomson TH 331 (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Thu, 01 Mar 2012 23:02:23 -0700; That sounds like it would be a potent amplifier. What was the looking glass program? Or would you have to shoot me after telling? Never heard of that tetrode, but I do have a GE industrial catalog of; /archives//html/Amps/2012-03/msg00024.html (9,204 bytes)
187. [Amps] 877 Amplifier Photo (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 04 Mar 2012 01:13:41 -0700; Jim Very nice work. Where's the tube in the photos? 73 John K5PRO _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/am; /archives//html/Amps/2012-03/msg00053.html (7,622 bytes)
188. Re: [Amps] 6kW Coax (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Mon, 12 Mar 2012 10:12:41 -0700; I've been following the thread here with interest, combining RF amplifier pallets for 12 kW total. And I would agree that rigid line is the safest design, and is what I would use if it were my projec; /archives//html/Amps/2012-03/msg00144.html (10,577 bytes)
189. [Amps] Guidelines.....toroids for tank ckts (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Mon, 26 Mar 2012 17:07:54 -0700; Peanut butter at least has low magnetic loss tangent. I would think it would have a high and unstable dielectric loss tangent as it heats readily at 2450 MHz. Sometimes I heat it to get it flowing ag; /archives//html/Amps/2012-03/msg00274.html (9,534 bytes)
190. Re: [Amps] question for you experts - RF choke on antenna to ground (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 28 Mar 2012 09:02:24 -0700; Medium Wave broacasters usually have a big RF choke to ground on their output, installed in the ATU, especially for series fed towers. It is typically called the 'static drain' and sold by Harris, LB; /archives//html/Amps/2012-03/msg00301.html (7,929 bytes)
191. [Amps] amp cooling / triodes vs tetrodes (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Wed, 04 Apr 2012 00:42:39 -0600; The maker of the TH628 tetrode in France tests them without bias switching. With 5 Amps of idling Ib, at 28 kV, there's 140 kW kW of plate dissipation just from the electron beam with no RF drive. In; /archives//html/Amps/2012-04/msg00049.html (7,995 bytes)
192. [Amps] Plate blocking cap voltage (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 07 Apr 2012 19:50:47 -0600; If the capacitor is a blocker, then you would want it to have enough nanofarads to make a low value of Xc at the worst case (lowest) frequency, while not being far past self-resonance into higher XL.; /archives//html/Amps/2012-04/msg00085.html (8,222 bytes)
193. [Amps] Who still sells HV Capacitors (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 10 Apr 2012 22:57:36 -0600; Almost all of the original companies besides Aerovox are still making them in the USA, with oil and paper or plastic film, just what is needed. There are some standard case sizes that can be specifie; /archives//html/Amps/2012-04/msg00096.html (8,245 bytes)
194. Re: [Amps] Who still sells HV Capacitors (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 11 Apr 2012 19:45:36 -0600; I have no idea these days, as its been a decade since I bought any at work. I am guessing around $100 for something like 4 uF. 20 should cost more. I may be way off though. John --Original message--; /archives//html/Amps/2012-04/msg00104.html (8,959 bytes)
195. [Amps] Filter capacitors and L-input filters (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Mon, 16 Apr 2012 10:54:44 -0600; Here is an old report on the problems inherent in LC and multiple LC section power supply filters for transmitters, for those who want to read about it but don't design around it: http://www.amwindow; /archives//html/Amps/2012-04/msg00162.html (8,341 bytes)
196. [Amps] More Capacitors vs LC filters (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 17 Apr 2012 11:24:52 -0600; Even 2 kJ is dangerous. The large GE capacitors that we use at work, run about 4 kJ each in operation. In 2001, we began to loose them, explosively. Each time, the metal can peeled open like a can op; /archives//html/Amps/2012-04/msg00170.html (8,303 bytes)
197. [Amps] More Capacitors vs LC filters (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 18 Apr 2012 13:47:07 -0600; One more thing about big oil-filled capacitors: When the voltage gets above about 10-12 kV, manufacturers build their capacitors with series capacitor packs. Each one is wound paper or film with foil; /archives//html/Amps/2012-04/msg00177.html (8,927 bytes)
198. [Amps] homebrew SK-2216 chimney (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Thu, 19 Apr 2012 15:16:16 -0600; Interesting. We're using the same hose, in 2 inch diameter, for the plate cooling hoses on the 200 MHz QRO amplifier at work. It works very well with high voltage, but I had no RF fields near it. 73; /archives//html/Amps/2012-04/msg00186.html (7,842 bytes)
199. Re: [Amps] Tubes vs. Solid State (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 1 May 2012 16:01:34 -0600; Manfred, thank you for your sage advice and comments. Sounds like a fun project. I am stuck working with large tube amplifiers, a career path that has somehow fallen my way, so I don't get to play wi; /archives//html/Amps/2012-05/msg00035.html (9,476 bytes)
200. [Amps] RF tube performance simulator (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 22 May 2012 13:31:16 -0600; Thanks to Carel, PC5M, for contributing this tool to the collective here. It looks very interesting, I hope to give it a try soon. 73 John K5PRO _______________________________________________ Amps m; /archives//html/Amps/2012-05/msg00315.html (6,854 bytes)

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