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261. [Amps] Cool Amp Silver Plating (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 01 Mar 2014 13:57:44 -0700; We use it often at work. It's expensive. It doesn't do squat for improving the conductivity of surfaces like cavities and inductors for RF current, as Peter pointed out. That requires at least 3 to 5; /archives//html/Amps/2014-03/msg00010.html (8,518 bytes)
262. [Amps] Cool Amp Silver Plating Powder (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 02 Mar 2014 13:57:38 -0700; Correction to what I posted.... I use 0.0006" thick electroplated silver for 200 MHz cavity circuits, running about 2000 amperes RMS circulating current. My finger slipped a digit. 0.006 would be a r; /archives//html/Amps/2014-03/msg00011.html (7,620 bytes)
263. [Amps] new Freescale LDMOS part (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Wed, 12 Mar 2014 00:21:31 -0600; I wonder if anyone has had a chance to look at the new MMRF1006H part from Freescale. It appears tailored for 10-500 MHz, with 24 dB gain at the low frequencies, 50 VDC, 1 kW CW. Might be costly thou; /archives//html/Amps/2014-03/msg00045.html (6,635 bytes)
264. [Amps] tetrodes operating VHF, common grid (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 18 Mar 2014 23:17:32 -0600; 4CX5000A isn't a great VHF tube, Eimac 4CX3500A is better due to lower cathode lead inductance and shorter height. I did a comparison of the 4CX3500A in grounded grid (with bias) and grounded cathode; /archives//html/Amps/2014-03/msg00112.html (8,804 bytes)
265. [Amps] 4CX1600B options (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 05 Apr 2014 17:24:31 -0600; I have a Ten Tec Titan II model 416 with a supposedly bad tube, according to the factory. I haven't high potted it yet, and with an ohmmeter I measured clear between elements except there is 1.2 Meg; /archives//html/Amps/2014-04/msg00059.html (9,042 bytes)
266. [Amps] antenna analyzer (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 05 Apr 2014 22:00:17 -0600; The method described below, of placing the design resistance across the tube or socket, is correct when determining if your matching and tuning are in the ballpark. It is difficult with a cavity or t; /archives//html/Amps/2014-04/msg00063.html (9,974 bytes)
267. [Amps] dual cavity (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 08 Apr 2014 22:46:53 -0600; Yes, you can. Tune them into 50 ohm load individually. I prefer using 90 deg combiner like a branch (ring), or coupled line hybrid. Since you are dealing with a narrow band amp, these are fine, and y; /archives//html/Amps/2014-04/msg00103.html (7,962 bytes)
268. [Amps] Filament Voltage Question (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Fri, 25 Apr 2014 23:39:25 -0600; When direct heated filaments of thoriated tungsten (usually 1-2% thoria) have a lot of hours of operation (thousands), they become brittle and easy to break. Older tubes are much more prone to shippi; /archives//html/Amps/2014-04/msg00223.html (10,918 bytes)
269. [Amps] Filament Growth Question (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 26 Apr 2014 22:19:01 -0600; Matt You are likely correct that grain refinement is leading to brittleness in old filaments. I don't understand the metallurgy. 20 years ago I heard from RCA that high anode dissipation led to grain; /archives//html/Amps/2014-04/msg00227.html (8,781 bytes)
270. Re: [Amps] low pass filter fail (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Tue, 29 Apr 2014 23:08:36 -0600; Built a lambda/4 stub out of 9 inch diameter EIA hard line, for the big amps at work. It was build primarily to pass a tuning shaft through the output line to the variable capacitor paddle for output; /archives//html/Amps/2014-04/msg00257.html (10,132 bytes)
271. [Amps] 3CX800A7 Spares - cook them periodically? (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Mon, 14 Jul 2014 23:13:40 -0600; The 3CX800A7s shouldn't leak sitting on the shelf. Keep them stored away from extreme temperatures (freezing and hot) and Rip Van Winkle tubes should be ready to use after a 30-60 minute wait after t; /archives//html/Amps/2014-07/msg00049.html (10,787 bytes)
272. [Amps] Ion Pump (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 19 Jul 2014 13:29:08 -0600; Ion Pumps are worthy of a wikipedia check. They are used in high vacuum systems, once the vacuum is established with a roughing pump such as a Roots blower style or mechanical chug-chug recipocating.; /archives//html/Amps/2014-07/msg00076.html (8,014 bytes)
273. [Amps] 3CX800A7 Spares - cook them periodically? (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 19 Jul 2014 13:41:53 -0600; Damping resistances is a more general term for the more specific types like parasitic suppressors (which are slightly tuned to damp only higher frequency - VHF - spurious energy). Over the big pond t; /archives//html/Amps/2014-07/msg00077.html (9,661 bytes)
274. [Amps] Ion Pump (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 20 Jul 2014 13:12:30 -0600; Although this doesn't have much to do with the building of amplifiers, it does shed insight into some of the complications of making good tubes and how the technology there has impacted other industr; /archives//html/Amps/2014-07/msg00084.html (9,253 bytes)
275. [Amps] Experience with Heart Pacemakers? (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sat, 02 Aug 2014 16:45:22 -0600; At work the industrial hygenists have decided to post little warning stickers on every piece of RF producing equipment including my amplifiers. They warn people with implanted medical devices to avoi; /archives//html/Amps/2014-08/msg00014.html (7,177 bytes)
276. Re: [Amps] Experience with Heart Pacemakers? (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 03 Aug 2014 13:10:33 -0600; Being an old schooler myself, I tried to reason with a 'specialist'. I explained that some of the equipment they were labeling would emit far lower RF levels than their smartphone, comparable with ra; /archives//html/Amps/2014-08/msg00020.html (9,803 bytes)
277. [Amps] B&W L1000A power amp (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Sun, 17 Aug 2014 22:59:44 -0600; There is one nearby that needs a new home. Dual 813s, grounded grid amplifier, built in power supply. The components are hefty, and the amplifier is large. Includes manual. Pick up near Santa Fe, NM.; /archives//html/Amps/2014-08/msg00046.html (6,631 bytes)
278. [Amps] recent QRO amplifier installations (score: 1): Author: jtml@losalamos.com; Date: Thu, 11 Sep 2014 18:48:18 -0600; For a look (and a paper download) at some large RF power amplifiers in scientific installations you can download the PDFs of papers, from this link: https://oraweb.cern.ch/pls/linac2014/TOC.htm Then; /archives//html/Amps/2014-09/msg00012.html (6,825 bytes)
279. [Amps] HV diodes, now new PA's (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Fri, 17 Oct 2014 23:02:08 -0600; Now that Ten Tec is part of RF Concepts, I'd guess that the design of a new PA would come from them in Colorado, and TT might build it, or not. Hard to guess what is their long term plan. TT made qui; /archives//html/Amps/2014-10/msg00153.html (9,347 bytes)
280. [Amps] SOTA Solid State amplifiers (score: 1): Author: John Lyles <jtml@losalamos.com>; Date: Mon, 20 Oct 2014 00:34:37 -0600; Manfred Mornhinweg, Warren Pratt and others have added some healthy and interesting topics to this discussion on amplifiers. Whereas most of the chatter is usually particulars of various brands of mo; /archives//html/Amps/2014-10/msg00207.html (7,062 bytes)

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