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101. [Amps] Tuning tetrode amps (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 31 Jan 2010 13:00:12 -0700; Here is a link to Burle Industries app note TP122, on screen current and tetrode amplifiers. http://www.burle.com/moretube.htm Absolutely true! You can still tune and try and find the plate current d; /archives//html/Amps/2010-01/msg00590.html (7,076 bytes)
102. [Amps] 4CX3000A vs 5000A (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 16 Feb 2010 18:40:46 -0700; They have completely different sockets, better price that to see if you can afford it. The 5000 will play at 100 MHz, in the proper version of the socket. For what that's worth to you.... also, depen; /archives//html/Amps/2010-02/msg00456.html (8,019 bytes)
103. [Amps] kW dummy load resistors (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Thu, 18 Feb 2010 23:08:44 -0700; Two sources of non-inductive high power tubular resistors: Cesiwid, Kanthal-Globar or whatever they are called now (used to be Carborundum Co). They make resistors that are about 300 watts rating, th; /archives//html/Amps/2010-02/msg00550.html (7,404 bytes)
104. [Amps] Tuned choke input filter for PS (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 21 Feb 2010 17:29:01 -0700; Three phase power supplies can get away with smaller L and C, higher ripple frequency too. They are great for high power RF transmitters. But most hams and a lot of small broadcasters don't have thre; /archives//html/Amps/2010-02/msg00623.html (11,434 bytes)
105. [Amps] 120 Hz hum, LC filters (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 21 Feb 2010 18:42:32 -0700; There is some information here from the old GE Ham News, on power supply dynamic regulation, on the AM Window: http://www.amwindow.org/tech/htm/tutor.htm Also a paper by Wallace Walhgren of the forme; /archives//html/Amps/2010-02/msg00626.html (7,481 bytes)
106. [Amps] Tranformer construction webpages (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 23 Feb 2010 10:17:55 -0700; I agree with Steve, Manfred's treatise on transformer construction is first class. Loaded with very practical advice and it demonstrates that he has much experience in making transformers. I only mad; /archives//html/Amps/2010-02/msg00698.html (9,066 bytes)
107. [Amps] Teflon power capacitor (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 16 Mar 2010 00:16:47 -0600; PTFE, virgin white Teflon sheet, has relative dielectric constant of 2.1. Very stable even with temperature. And very low loss, so good that it is typically used for microwave insulators, next to pol; /archives//html/Amps/2010-03/msg00293.html (8,551 bytes)
108. [Amps] 833 amp (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 16 Mar 2010 23:44:06 -0600; The 833, while magnificant looking for a glass tube, sort of industrial 1940s look, was not a particularly high frequency tube. You would have troubles making it play at 10 meters, for instance. Neut; /archives//html/Amps/2010-03/msg00319.html (9,287 bytes)
109. [Amps] Teflon dielectric variable capacitor (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 16 Mar 2010 23:51:14 -0600; Carel I am pleased that you checked into this and did the calculations. As you see, the smaller the air gap, the worst off it can become. Its almost better to have a big air gap betwen a big slab of; /archives//html/Amps/2010-03/msg00320.html (8,245 bytes)
110. [Amps] B&W 800 RF choke (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 21 Mar 2010 10:43:27 -0600; I used one as a screen choke at 2800 KHz, in a 100 kW amplifier at work. It was fine there, but not sure about 1900. This was 12 years ago. I took data on a B&W 800 using a vector impedance meter and; /archives//html/Amps/2010-03/msg00442.html (6,750 bytes)
111. [Amps] big capacitor in HV PS (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Sun, 21 Mar 2010 21:33:57 -0700; The stored energy in that capacitance at 3.6 KVDC is 8.1 kilojoules. This is a tremendous amount to deal with for a power supply. Roughly equivalent to the mechanical force of a part of a stick of dy; /archives//html/Amps/2010-03/msg00456.html (8,460 bytes)
112. [Amps] When to stop - capacitors for power supplies (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 23 Mar 2010 10:52:46 -0700; Agreed. We are paid to do good but not ridiculous engineering. Leave that for Hollywood. Or Star Wars (the project, not the movie). For serious high power (3 kW to Terrawatts), three phase service i; /archives//html/Amps/2010-03/msg00499.html (7,294 bytes)
113. [Amps] building your own amplifier again (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Fri, 26 Mar 2010 10:41:22 -0600; VE7RF makes a pretty strong argument towards using bigger tubes like YU156, instead of trying to squeeze a kW or 2 out of an 8877 or pair of glass triodes. I think he is on to something as far as dol; /archives//html/Amps/2010-03/msg00648.html (11,236 bytes)
114. [Amps] coaxial stub on amplifier output (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Mon, 29 Mar 2010 21:28:24 -0600; Has anyone seen anything in print about using a lambda/4 (Quarter wavelength) stub on the output of an amplifier with a tube. Its a nice way to bring water, tuning mechanisms into an output circuit,; /archives//html/Amps/2010-03/msg00842.html (7,034 bytes)
115. [Amps] 1/4 wave shorted stubs on amp output (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 30 Mar 2010 11:39:07 -0700; It is for a cavity amplifier, with capacitive-coupled output paddle. Coax is 9 3/16 inch EIA, so I despise having to modify it. The stub is designed on paper and in machine shop, having an acme threa; /archives//html/Amps/2010-03/msg00887.html (12,300 bytes)
116. [Amps] gg feedthru power (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Tue, 30 Mar 2010 19:25:47 -0700; In Eimac Amateur Service Newsletter AS-33, also in QST in June of 1967, Bill Orr and Bill Sayer (both at Eimac) state this: "Strictly speaking, the extra output power is not 'free', as r.f. power is; /archives//html/Amps/2010-03/msg00919.html (8,144 bytes)
117. [Amps] TX site RFI and automobiles (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 31 Mar 2010 14:10:37 -0700; At the scenic overlook on Sandia Crest, over Albuquerque, there is a warning sign about the RFI levels affecting car alarms. In 2008, I drove my Jetta there with friends, and the keyfob was unable to; /archives//html/Amps/2010-03/msg00971.html (7,913 bytes)
118. Re: [Amps] Amps Digest, Vol 87, Issue 117 (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 31 Mar 2010 14:44:11 -0700; Carl, I didn't build the Tyler output modification, as the tube manufacturer in France doesn't recommend 'efficiency improvements' via plate current waveform modification. Although i did notice a cop; /archives//html/Amps/2010-03/msg00973.html (8,758 bytes)
119. [Amps] Class F PA circuit tricks to improve efficiency (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 31 Mar 2010 14:46:00 -0700; This time i added a subject line, sorry. Carl, I didn't build the Tyler output modification, as the tube manufacturer in France doesn't recommend 'efficiency improvements' via plate current waveform; /archives//html/Amps/2010-03/msg00974.html (8,478 bytes)
120. [Amps] real component measurements at RF (score: 1): Author: "John Lyles" <jtml@losalamos.com>; Date: Wed, 31 Mar 2010 15:18:25 -0700; W7IUV's recent posting makes sense as to the pitfalls of measuring L and C with the various commercial instruments. There is one other device that wasn't mentioned, but is a less expensive alternativ; /archives//html/Amps/2010-03/msg00976.html (9,523 bytes)

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