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161. [Amps] Memorial Day weekend amplifier fun/work (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Mon, 30 May 2011 17:20:12 -0600
After a week of troubles with the plate water flow interlock, we changed technologies, and got no more trips. I started a long term heat run Saturday morning, for the TH628 VHF power amplifier that I
/archives//html/Amps/2011-05/msg00278.html (7,356 bytes)

162. Re: [Amps] Any designs for 4CX1000A on 2m (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 7 Jun 2011 17:12:26 -0600
That's impressive, I wonder how far they are derated the 4CX5000A at 220 MHz, in that amplifier. I tried using the 4CX5000A in a 5 kW FM broadcast amplifier in the early 1980s and found it difficult,
/archives//html/Amps/2011-06/msg00093.html (7,488 bytes)

163. [Amps] Any designs for 4CX1000A on 2m - RS2104 and 4CX5000A (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Wed, 8 Jun 2011 13:39:55 -0600
That last digest had a large amount of duplication and was hard to read through, but your comment on RS2014, Bill, indicates that the tubes were not Eimac but Seimens tubes, versions of the same 4CX5
/archives//html/Amps/2011-06/msg00107.html (7,426 bytes)

164. [Amps] KG7HF 70 cm amplifier on Facebook (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 11 Jun 2011 15:14:56 -0600
Fantastic. Want to see photos of the guts, the power amplifier box - inside! Which tube? 60% efficient. 73 John K5PRO -- My new 70 cm amp is almost done, time for some on the air testing during the c
/archives//html/Amps/2011-06/msg00148.html (6,984 bytes)

165. [Amps] K5PRO is OK from the fire at Los Alamos (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 28 Jun 2011 16:20:19 -0600
THANKS, Shane, no structures burned yet, and the fire fighters are incredible. I live down in the valley below the 'hill' so am watching it from here, just lots of smoke. My amplifiers are up there,
/archives//html/Amps/2011-06/msg00311.html (7,661 bytes)

166. [Amps] High Voltage Engineering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 04 Jul 2011 14:57:59 -0600
Was that the same company started by Robert Van Der Graff in the 1930s Carl? 73 John K5PRO _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contestin
/archives//html/Amps/2011-07/msg00032.html (7,064 bytes)

167. [Amps] Value, part 3 (final) (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 16 Jul 2011 16:30:47 -0600
Seeing what transpired, I can only say that those best offers weren't so far off the mark for used old tubes. The 4-1000A seems low-balled, as they are kind of rare now and there are a few HB or BCB
/archives//html/Amps/2011-07/msg00192.html (7,810 bytes)

168. [Amps] Any new tube research? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 16 Aug 2011 12:01:44 -0600
Ignoring more exotic tubes like gyrocons, gyrotrons, TWTs, relativistic electron devices, things that the Naval Research Lab is doing, there is still vacuum tube improvement being done in the industr
/archives//html/Amps/2011-08/msg00069.html (11,113 bytes)

169. [Amps] 2 ways of Gettering... (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 13 Sep 2011 13:40:18 -0600
Actually the getter is there all the time and what you are speaking about is how to reactivate the gettering process. By heating "some" metallic getters such as coated plates, they attract more ions
/archives//html/Amps/2011-09/msg00070.html (8,658 bytes)

170. [Amps] Getters (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Wed, 14 Sep 2011 08:18:09 -0600
Good enough. I did have a 3-500Z switch tube in my 314R1 broadcast transmitter go bright yellow on the plate when the clamp diode was shorted across it. The plate overload saved it but for a moment i
/archives//html/Amps/2011-09/msg00091.html (7,320 bytes)

171. [Amps] some more tetrode questions (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Wed, 14 Sep 2011 08:36:35 -0600
I agree with Carl (and Ed) about raising the grids DC off ground and still running GG for RF. Raising the plate V on a 4-1000 with zero bias will raise zero signal idling current and grid current. Th
/archives//html/Amps/2011-09/msg00094.html (9,578 bytes)

172. [Amps] Distilled water in dummy load (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 29 Nov 2011 13:37:12 -0700
Jim and all, I've spent a lot of time for the past two years with high power liquid-cooled loads. The globar resistor assembly sounds neat. The popular high power resistor loads that have water hose
/archives//html/Amps/2011-11/msg00175.html (11,671 bytes)

173. [Amps] Silver plated Cu strap sources? (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Tue, 6 Dec 2011 13:24:54 -0700
Contact Kintronic Labs for copper strap, also silver plated: http://www.kintronic.com/products/productInfo.aspx/Copper/ _______________________________________________ Amps mailing list Amps@contesti
/archives//html/Amps/2011-12/msg00049.html (7,372 bytes)

174. [Amps] Warm up and on time question... PWM ramping (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 17 Dec 2011 12:09:08 -0700
In a crude way, the SCR/Triac dimmers for lighting do this. Collins and later Continental Electronics had their HV and screen voltage soft started by a similar AC cycle chopping, using SCRs in the pr
/archives//html/Amps/2011-12/msg00134.html (8,415 bytes)

175. [Amps] Is after-powerdown cooling desirable? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 19 Dec 2011 21:59:30 -0700
All the large ceramic/metal tubes that I use require a cool-down period after the filament is completely extinguished, before fans blowing through the base of the tube, and anode water stop. I've des
/archives//html/Amps/2011-12/msg00148.html (9,402 bytes)

176. [Amps] Stripline design (score: 1)
Author: "John Lyles" <jtml@losalamos.com>
Date: Fri, 6 Jan 2012 09:05:18 -0700
Paul There are some pretty decent texts and articles that may help you grasp stripline and coaxial amplifier circuits, if you'd like to know more than just cutting and trying approach. The west coast
/archives//html/Amps/2012-01/msg00090.html (9,848 bytes)

177. Re: [Amps] strategies for storing spares for maximum life ?? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 22 Jan 2012 13:37:19 -0700
The best advice I have heard from one tube mfr, and follow at work, is to not store tubes out in containers or storage units where temperature extremes will be present. With tubes worth $30K-$300K e
/archives//html/Amps/2012-01/msg00170.html (9,304 bytes)

178. [Amps] tetrode reverse screen grid current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 28 Jan 2012 23:28:17 -0700
This characteristic is quite normal for many tetrodes, as others have suggested here. Sometimes it can be inferred from looking at the characteristic 'constant current' curves, when the screen curren
/archives//html/Amps/2012-01/msg00250.html (9,644 bytes)

179. Re: [Amps] tetrode reverse screen grid current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 29 Jan 2012 13:41:25 -0700
Problem is, most electronic regulators are not designed to be both source and sink capable. That's why it was suggested to add a heavy bleeder, that tames the regulator circuit by allowing it to deli
/archives//html/Amps/2012-01/msg00271.html (9,073 bytes)

180. Re: [Amps] tetrode reverse screen grid current (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 29 Jan 2012 13:44:04 -0700
I'm think you could work out an automatic circuit that sensed when to load the supply, when current is coming back into it. That is essentially a shunt regulator of sorts. Just more complexity than a
/archives//html/Amps/2012-01/msg00272.html (8,762 bytes)

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