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141. Re: [Amps] making aluminum heat sinks black (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 22 Jul 2006 15:06:26 +0100; If you're going to blow air over it, black colour will contribute little, if anything. Anodising (not sure of the term used elsewhere) is the usual black treatment - with paint the thermal resistance; /archives//html/Amps/2006-07/msg00856.html (8,238 bytes)
142. Re: [Amps] making sinks black (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 22 Jul 2006 18:03:06 +0100; It will depend a lot on the situation - reasonable convection will dominate over radiation, so black won't make much difference where there's forced air, or vertical orientation with free airflow. Ma; /archives//html/Amps/2006-07/msg00879.html (8,442 bytes)
143. Re: [Amps] making sinks black (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 23 Jul 2006 08:08:41 +0100; If the fins are too close together, then the convection airflow between them can get choked with turbulence and, again, the heat loss ends up little better than a solid block. I tried an experiment; /archives//html/Amps/2006-07/msg00915.html (8,816 bytes)
144. Re: [Amps] The maximum amount of 811As and 572Bs in parallel (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 24 Jul 2006 07:40:19 +0100; Yes, but do you get the same useful output power from a distributed amplifier unless you have two antennas to feed? Doesn't half the output go into a terminating resistor? Steve _____________________; /archives//html/Amps/2006-07/msg01002.html (8,631 bytes)
145. Re: [Amps] Looking for info: SRF7053 device (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 24 Jul 2006 23:02:12 +0100; When Motorola pulled the plug on all but BTS devices, M/A Com took over the rf power lines, lower power stuff and linear devices went to Microsemi. I don't know what's happened since then, but severa; /archives//html/Amps/2006-07/msg01033.html (8,081 bytes)
146. Re: [Amps] Looking for info: SRF7053 device (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 24 Jul 2006 23:20:53 +0100; Tracing the circuit - especially any bias circuits - should help identify FET from bipolar. If the amp has a model number, you might be able to find marketing blurb which might say what device techno; /archives//html/Amps/2006-07/msg01042.html (7,802 bytes)
147. Re: [Amps] 3-500Z convertion (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Tue, 25 Jul 2006 16:51:44 +0100; If they're the ones I'm thinking of, the screen grid connection is a beast unless you have the proper socket. Steve _______________________________________________ Amps mailing list Amps@contesting.c; /archives//html/Amps/2006-07/msg01088.html (8,465 bytes)
148. Re: [Amps] Amps Digest, Vol 43, Issue 134 (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Tue, 25 Jul 2006 19:50:11 +0100; Far less than the effect of a local cell BTS.... Far less than the programme material.... I could use a pair - leakage to the earlobes might just keep the gray cells awake :-) Steve _________________; /archives//html/Amps/2006-07/msg01107.html (8,433 bytes)
149. Re: [Amps] MOSFET biasing (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Wed, 26 Jul 2006 07:34:44 +0100; Danny Pease wrote: Anyone have any experience with biasing MOSFET's for linear service, specifically the MRF174? I have a 144 MHz 600 watt amp that uses 3 boards of pairs in push-pull. The existing b; /archives//html/Amps/2006-07/msg01143.html (8,408 bytes)
150. Re: [Amps] Flash arcs (score: 1): Author: "Steve Thompson" <g8gsq@eltac.co.uk>; Date: Fri, 28 Jul 2006 07:40:33 +0100; Be careful - he might be a Scot (or Welshman or Irishman) living in England. It can be dangerous labelling them (or someone from Cornwall) as being English! Steve (nearly all English) _______________; /archives//html/Amps/2006-07/msg01229.html (8,216 bytes)
151. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sat, 29 Jul 2006 22:42:12 +0100; The major effect of ripple current is internal heating, so it's pretty much all about temperature in the end. It's interesting to work out the max. allowed internal temp from 85 (or 105C) + Iripple^2; /archives//html/Amps/2006-07/msg01326.html (9,072 bytes)
152. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 30 Jul 2006 20:10:08 +0100; Do you know when this was? I'd like to know which date codes to avoid. Thanks, Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/; /archives//html/Amps/2006-07/msg01400.html (9,034 bytes)
153. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Sun, 30 Jul 2006 22:03:05 +0100; Sorry, I think I didn't make myself clear. When did Eimac change their recipe? Thanks, Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contest; /archives//html/Amps/2006-07/msg01404.html (9,484 bytes)
154. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 09:01:26 +0100; Isn't that about 25 years before 3-500Z was introduced? In the 40s they were making lots of devices running high power at high VHF/low UHF so they must have had good enough glass. I think 3-500Z was; /archives//html/Amps/2006-07/msg01419.html (10,710 bytes)
155. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 09:26:13 +0100; Please ignore my previous post - just realised I misinterpreted Rich's reply. I still don't believe in glass that's ok at 30MHz but duff at 100odd though. Steve ______________________________________; /archives//html/Amps/2006-07/msg01420.html (8,652 bytes)
156. [Amps] GS35 anode cooler (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 18:08:18 +0100; Soldering to the anode cooler is easier if you remove the cooler and pre-heat it in the oven. steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.; /archives//html/Amps/2006-07/msg01440.html (7,471 bytes)
157. Re: [Amps] Glass melting, f, and D-factor (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 18:16:57 +0100; For clarity - what Rus reported happened to what model of tube made by who? Did Rus see it himself? Was it a one off or reliably repeatable? Thanks, Steve ____________________________________________; /archives//html/Amps/2006-07/msg01441.html (7,137 bytes)
158. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 18:38:47 +0100; Sounds very complicated. A bit of reactance in the load line is all that's needed to get dissipation up. Given that the circuit has to come up with 360deg of phase shift somewhere in order to oscilla; /archives//html/Amps/2006-07/msg01442.html (10,281 bytes)
159. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Mon, 31 Jul 2006 18:41:12 +0100; It's not whether it increases but by how much as a percentage and to what value in absolute terms. Steve _______________________________________________ Amps mailing list Amps@contesting.com http://l; /archives//html/Amps/2006-07/msg01443.html (9,863 bytes)
160. Re: [Amps] Ameritron Amps (score: 1): Author: Steve Thompson <g8gsq@eltac.co.uk>; Date: Tue, 01 Aug 2006 07:18:51 +0100; Is there any form of manufacturing defect, or damage, which could account for what happened? Rich, please clarify: Are we talking about an Eimac 3-500Z? Who witnessed this happen? Did it happen more; /archives//html/Amps/2006-08/msg00000.html (6,992 bytes)

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