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21. [Amps] 5CX1500A (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Thu, 06 May 2010 09:55:42 +0100; A local radio club has one to sell - NOS, boxed, Eimac. It's come from spares stock at a physics research place. Anyone here interested? Equally, I'd welcome suggestions as to value. Thanks, Steve __; /archives//html/Amps/2010-05/msg00066.html (6,204 bytes)
22. Re: [Amps] More parasitic choke questions (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Tue, 27 Jul 2010 07:35:45 +0100; What is preferred about carbon comp? Given the heat and the need for long term stability in value they're the least suitable component you could choose. Some years ago I measured some different supp; /archives//html/Amps/2010-07/msg00246.html (7,716 bytes)
23. Re: [Amps] More parasitic choke questions (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Tue, 27 Jul 2010 17:23:14 +0100; Maybe we have different ways of visualising what the suppressor is doing and how it does it. With regard to stability, I wasn't meaning the few % of tolerance or temperature drift, but the factor of; /archives//html/Amps/2010-07/msg00251.html (10,907 bytes)
24. Re: [Amps] More parasitic choke questions (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Wed, 28 Jul 2010 07:47:38 +0100; Here's the one from 30/8/06, which details measurements on some suppressors, plus a brief explanation of how I think suppressors should be analysed. http://lists.contesting.com/archives//html/Amps/20; /archives//html/Amps/2010-07/msg00278.html (8,418 bytes)
25. Re: [Amps] for 2KL (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sat, 07 Aug 2010 07:21:33 +0100; 2SC2652 runs off 48 or 50V, the same as MRF150. Toshiba stopped making them a while ago which might have prompted the end of the product. Steve _______________________________________________ Amps ma; /archives//html/Amps/2010-08/msg00075.html (6,755 bytes)
26. Re: [Amps] Can I cool too much the tubes? (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Tue, 24 Aug 2010 08:15:28 +0100; I've observed this across a wide range of class AB linear amplifiers - device dissipation is very roughly constant between 10 and 100% output. With a tube amp you can adjust the tuning to get higher; /archives//html/Amps/2010-08/msg00359.html (9,075 bytes)
27. Re: [Amps] Amps Digest, Vol 93, Issue 11 (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Fri, 10 Sep 2010 23:16:22 +0100; I've always known it as 'back to back'. A 35A bridge can be had for a dollar or three - cross wire the connections and you get 70A worth of diodes in both directions and you'll have a fixing hole to; /archives//html/Amps/2010-09/msg00073.html (8,295 bytes)
28. [Amps] Re WTB RG-393 (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sun, 12 Sep 2010 22:24:50 +0100; If you can't find RG393, RG142 is similar but solid inner so not so flexible and RG400 is multi strand inner but single screen. Good quality RG400 has enough braid in the screen that double screen do; /archives//html/Amps/2010-09/msg00132.html (6,651 bytes)
29. Re: [Amps] RG-393 source (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Tue, 14 Sep 2010 07:36:31 +0100; Apologies for the confusion - the data I glanced at is laid out oddly and appears to group RG393 with RG142 sizes unless you look closely. There's a lesson there.... Steve ___________________________; /archives//html/Amps/2010-09/msg00160.html (6,883 bytes)
30. Re: [Amps] SHV / proper cable for DC energy transfer (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Thu, 16 Sep 2010 08:58:19 +0100; I haven't tried to find exact details of anyone's test process but I suspect that the cable manufacturers specify the breakdown voltage with a flat cut end on the cable, or with the cable prepared as; /archives//html/Amps/2010-09/msg00202.html (7,301 bytes)
31. Re: [Amps] Skin depth: silver plating of tank circuit coil feasible with (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 04 Oct 2010 21:50:40 +0100; I recall an article in RF Design magazine which suggested that the rf current moves away from high resistivity, I think there was some maths supporting the analysis. If the outer surface of a (e.g. c; /archives//html/Amps/2010-10/msg00011.html (13,819 bytes)
32. Re: [Amps] Skin depth: silver plating of tank circuit coil feasible with (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Tue, 05 Oct 2010 08:18:37 +0100; Yes and no appears to be the answer - rf current doesn't take the lowest possible resistance path, it crowds on the outside surface of a conductor. Once there it appears to look for the lowest resist; /archives//html/Amps/2010-10/msg00024.html (7,977 bytes)
33. [Amps] Transformers (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Fri, 29 Oct 2010 10:57:48 +0100; Mainly for UK readers - I've just received a flyer from Pennine Radio Ltd with some indicative transformer prices: 1kVA - Ł70 2kVA - Ł110 5kVA - Ł220 Expect some surcharge for non standard voltages a; /archives//html/Amps/2010-10/msg00425.html (6,371 bytes)
34. Re: [Amps] HV rectifier strings - to bypass or not? (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sun, 31 Oct 2010 07:37:12 +0000; If there's a problem with spikes on the line, isn't it better to get rid of them with filtering at the line input so they don't reach the transformer in the first place? Steve bridge? _______________; /archives//html/Amps/2010-10/msg00475.html (9,245 bytes)
35. Re: [Amps] 3CX1000A7 and larger (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Wed, 17 Nov 2010 08:57:35 +0000; I work at John's (pre-) driver levels, but have just completed 20kW pulse amps for 214MHz. The output stage is 24 x Freescale MOSFETs, each running 4W in, just under 1kW out, which is pretty remarkab; /archives//html/Amps/2010-11/msg00292.html (8,464 bytes)
36. Re: [Amps] Fan for SB220 (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Fri, 17 Dec 2010 21:07:26 +0000; It's not surprising that the sides facing each other should get hotter than the rest - but a metal screen won't help by shielding heat. If it's shiny it just reflects the heat back and if it's black; /archives//html/Amps/2010-12/msg00193.html (8,259 bytes)
37. [Amps] Meter protection (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 20 Dec 2010 10:40:59 +0000; If you're trying to protect a 'bare' meter, where FSD is likely to be well below 0.7V, it's worth considering big Schottky diodes as the voltage drop is somewhat lower. Prices aren't high but if you'; /archives//html/Amps/2010-12/msg00281.html (7,640 bytes)
38. Re: [Amps] GS35B Needed (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Wed, 29 Dec 2010 23:11:17 +0000; Keep a look out for GS31B - I think it's the same tube with a different cooler and is often lower price. If the cooler from your GS35 survived, you could swap it over. Steve _________________________; /archives//html/Amps/2010-12/msg00407.html (6,827 bytes)
39. Re: [Amps] BVT problem (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 10 Jan 2011 09:19:49 +0000; And what does the primary current do? How does it behave with a load of 2-3Mohms (say 10 x 270k 1W or 20 x 150k 0.5W in series) on the secondary? Steve _______________________________________________; /archives//html/Amps/2011-01/msg00117.html (6,479 bytes)
40. Re: [Amps] 'heat spreader' sizing ?? (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sat, 05 Feb 2011 16:36:44 +0000; A potential problem with soldering a transistor down is ensuring there aren't any voids. Where transistors have a carrier and flange soldered together it's normal to do it in a reflow oven with an in; /archives//html/Amps/2011-02/msg00032.html (8,715 bytes)

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