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1. Re: [Amps] Amplifier scenario question (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Thu, 17 Sep 2009 22:48:50 +0100; Depends a lot on the amp in question. A well designed one will shut down before any harm is done. Steve _______________________________________________ Amps mailing list Amps@contesting.com http://li; /archives//html/Amps/2009-09/msg00235.html (7,587 bytes)
2. [Amps] Vacuum variable hipot (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Fri, 18 Sep 2009 12:03:26 +0100; I have a Jennings UCSL1000 - 1000pF, 5kV cap. If I put 5kV dc across it and run it through its tuning range, the leakage current is sometimes zero but fluctuates and there are places where the curren; /archives//html/Amps/2009-09/msg00236.html (6,611 bytes)
3. Re: [Amps] Vacuum variable hipot (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Fri, 18 Sep 2009 15:35:25 +0100; If I remember correctly, the Jennings test procedure uses AC and they test by applying voltage for a period, during which arcing can happen and then getting no arcs for a subsequent period - can't re; /archives//html/Amps/2009-09/msg00239.html (10,481 bytes)
4. Re: [Amps] finding a good blower in Europe? (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Wed, 23 Sep 2009 07:38:17 +0100; Have a look at Comair Rotron products. Their ambassador and spinnaker fans will easily cope, for example. These are dc powered, so you can have variable speed to keep the noise down. Steve __________; /archives//html/Amps/2009-09/msg00268.html (7,927 bytes)
5. Re: [Amps] PEP Reading Wattmeter (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 05 Oct 2009 21:45:58 +0100; Don't trust the accuracy - into a real aerial it's very dependent on the directivity of the coupler used. The VHF/UHF one is all but useless (25dB typ.) and they spout a load of nonsense in section; /archives//html/Amps/2009-10/msg00107.html (8,809 bytes)
6. Re: [Amps] Conservation of Energy! (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 07 Dec 2009 23:04:41 +0000; The original discussion revolved around 120V costing twice as much. That's a lot of I^2R! Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.con; /archives//html/Amps/2009-12/msg00201.html (8,885 bytes)
7. Re: [Amps] FW: Decent HF directional coupler for RF power meas. (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 07 Dec 2009 23:16:06 +0000; Not quite. They can calibrate the couplers all they like. Unless the directivity is high the readings are erroneous in the real world. The claimed directivity of their V/UHF couplers is awful and the; /archives//html/Amps/2009-12/msg00205.html (7,370 bytes)
8. [Amps] Electricity costs (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Tue, 08 Dec 2009 10:09:31 +0000; I copied Colin's post about 110/220V operating to a couple of friends. One replied: "It reminds me of my Nan. She had this electric fire running 3 bars all day. We suggested that it might be costing; /archives//html/Amps/2009-12/msg00223.html (6,350 bytes)
9. Re: [Amps] GS-35B efficiency (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sat, 19 Dec 2009 08:35:23 +0000; There's nothing subtle about a GS35b. See www.qsl.net/g8gsq/gs35a.jpg and www.qsl.net/g8gsq/gs35g.jpg for pics of a dead one that I opened up. If the 8877 is a Ferrari, the GS35b is a sidevalve V8, o; /archives//html/Amps/2009-12/msg00495.html (8,085 bytes)
10. Re: [Amps] GS-35B efficiency (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Mon, 21 Dec 2009 15:04:08 +0000; I'm guessing it will be down to how the tube 'bottoms' at saturation - that's going to affect the maximum voltage swing on the plate. That might inherent in the structure and spacings in the GS35. S; /archives//html/Amps/2009-12/msg00521.html (7,614 bytes)
11. [Amps] 3-500Z grid short question (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Tue, 09 Feb 2010 16:14:38 +0000; I'm looking at a TL922 for a friend. One tube has a grid - filament short, the same tube has an overheated filament pin. The solder has obviously reflowed at some point but hasn't totally run out of; /archives//html/Amps/2010-02/msg00281.html (7,025 bytes)
12. Re: [Amps] L-4PS Transformer Buzz (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Tue, 16 Feb 2010 07:38:55 +0000; Monitoring the primary line current might indicate if it's mechanical or electrical in origin. Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists; /archives//html/Amps/2010-02/msg00430.html (7,323 bytes)
13. Re: [Amps] Mangian wire (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 01 Mar 2010 07:53:48 +0000; The GS35b has an indirectly heated cathode, tied to one side of the heater. The connection from your bias circuit needs to go to that point, not to the centre of the heater transformer. The way you d; /archives//html/Amps/2010-02/msg00767.html (7,899 bytes)
14. Re: [Amps] 100 Ohm 2W (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sat, 13 Mar 2010 22:59:57 +0000; For the few pennies they cost, it's worth thinking about getting 3W metal oxide resistors. They withstand overload and high operating temperatures much better than carbon. To be fair to Rich, that's; /archives//html/Amps/2010-03/msg00218.html (7,137 bytes)
15. Re: [Amps] 100 Ohm 2W (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sun, 14 Mar 2010 10:07:45 +0000; Are any brands or families particularly bad? Including a tiny bit of lead length, a variety I have here all have around a couple of ohms of reactance at 30MHz - about 10nH. Some bigger ones, 5W ratin; /archives//html/Amps/2010-03/msg00244.html (8,378 bytes)
16. Re: [Amps] Good engineering (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 29 Mar 2010 07:46:02 +0100; The metal does migrate, dependent on temperature and current density. Aluminium is much worse than gold (these are the two metals mostly used in rf semiconductors). Amongst others, TRW published som; /archives//html/Amps/2010-03/msg00741.html (8,249 bytes)
17. Re: [Amps] Good engineering (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Mon, 29 Mar 2010 10:04:49 +0100; I think it's this last bit that David and I were referring to - electromigration. There's references to it in the old Motorola app notes AN1024, AN1025 and AN1027 on the Freescale web site (I think t; /archives//html/Amps/2010-03/msg00746.html (9,787 bytes)
18. Re: [Amps] Good engineering (score: 1): Author: Steve <g8gsq@f2s.com>; Date: Mon, 29 Mar 2010 10:08:50 +0100; Yes - and prepare for its effects at a larger scale as lead free solder takes over. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/m; /archives//html/Amps/2010-03/msg00747.html (7,773 bytes)
19. [Amps] Indirectly heated cathodes (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Sun, 04 Apr 2010 22:33:09 +0100; To avoid confusuon, it's the oxide cathode rather than the fil(ament) that can suffer from too low a heater voltage in an indirectly heated tube. I'm not sure about the 'narrow window'. Most tubes I; /archives//html/Amps/2010-04/msg00081.html (7,181 bytes)
20. Re: [Amps] How to clean tube fins (score: 1): Author: Steve Thompson <g8gsq@f2s.com>; Date: Mon, 26 Apr 2010 08:01:49 +0100; How long did you have to wait for the right callsign to come round? Steve PS - for non-UK and newer UK licensees, until recently UK calls were issued strictly in alphabetical order, no personal choic; /archives//html/Amps/2010-04/msg00654.html (8,575 bytes)

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