- 241. [AMPS] Sucking instead of Blowing (was - This guy is gotta be kidding!) (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 28 May 2001 12:56:14 +0100
- I do indeed trust you, Phil - that's exactly why I was asking about this. Yes, I've seen Rich's article, and there's absolutely no doubt that (a) the SB-220 cooling system was very carefully thought
- /archives//html/Amps/2001-05/msg00478.html (10,634 bytes)
- 242. [AMPS] Sucking instead of Blowing (was - This guy is gotta be kidding!) (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 28 May 2001 09:11:24 +0100
- All practical cooling fans create turbulence. It's easy to check with a streamer of smoke. Thank you - that's the information I was asking for. Can you confirm that the ink is on the opposite side fr
- /archives//html/Amps/2001-05/msg00479.html (10,365 bytes)
- 243. [AMPS] Sucking instead of Blowing (was - This guy is gotta be kidding!) (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 28 May 2001 22:28:24 +0100
- And that is because...? 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submis
- /archives//html/Amps/2001-05/msg00482.html (9,135 bytes)
- 244. [AMPS] Floating Ground (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 4 Apr 2001 13:22:34 +0100
- Although the article is associated with a specific commercial product, the general points are valid for all triode amplifiers. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist
- /archives//html/Amps/2001-04/msg00067.html (7,687 bytes)
- 245. [AMPS] ALPHA 77SX on 50Hz (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 6 Apr 2001 07:54:29 +0100
- Interesting figures... so the total weight of the transformer increases as something like the square of the core cross-sectional area. Seems about right. And then the capacity of a blower with an AC
- /archives//html/Amps/2001-04/msg00132.html (9,312 bytes)
- 246. [AMPS] ALPHA 77SX on 50Hz (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 6 Apr 2001 16:35:08 +0100
- My "seems about right" was based on the notion that although the core cross-section would only need to be 20% larger, a core built from standard off-the-shelf laminations would probably be larger in
- /archives//html/Amps/2001-04/msg00145.html (9,850 bytes)
- 247. [AMPS] MLA2500 and screen voltage for 4CX800. (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Wed, 11 Apr 2001 16:10:41 +0100
- John did the measurements and faxed me the screen dumps. I prepared the bar charts and the web page on my site. A few additional points: 1. The "need" for good screen regulation will depend on the ty
- /archives//html/Amps/2001-04/msg00254.html (12,671 bytes)
- 248. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 13 Apr 2001 08:46:21 +0100
- [...] You can't generalize either way on the basis of complexity alone. Complex circuits can offer design opportunities that don't exist in simple circuits; but they also have more to go wrong. In th
- /archives//html/Amps/2001-04/msg00300.html (12,570 bytes)
- 249. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Fri, 13 Apr 2001 19:53:54 +0100
- My, you must have led a sheltered life... 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: http://www.contesting.c
- /archives//html/Amps/2001-04/msg00302.html (9,145 bytes)
- 250. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sat, 14 Apr 2001 14:43:49 +0100
- The MOV or gas tube at the screen terminal is actually the *first* line of defense because that is where the arc hits. Tom correctly identifies that the screen bypass capacitor in the socket is at le
- /archives//html/Amps/2001-04/msg00324.html (11,731 bytes)
- 251. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sat, 14 Apr 2001 22:10:42 +0100
- Not true, on two counts. 1. Sometimes the arc is due to an RF problem external to the tube, such as a high SWR. 2. Sometimes the arc isn't any kind of RF problem at all. Many of mine have been due to
- /archives//html/Amps/2001-04/msg00343.html (10,852 bytes)
- 252. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 16 Apr 2001 10:01:13 +0100
- We are talking about power supplies, and the power supply doesn't care where the arc is. Only after you have provided a cathode bypass capacitor and re-wired the entire power supply. Although DC grou
- /archives//html/Amps/2001-04/msg00361.html (11,383 bytes)
- 253. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 16 Apr 2001 09:42:24 +0100
- I see what you mean now. Oh, that one... sure, you always need that. I thought you meant another impedance between the screen and the screen supply, which would help to protect the supply. That may w
- /archives//html/Amps/2001-04/msg00362.html (11,010 bytes)
- 254. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Mon, 16 Apr 2001 15:12:45 +0100
- Enough of these non-standard units! The last time I used the arc method to measure the length of the gap on a 4CX250, it was 1.0 earwig. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice'
- /archives//html/Amps/2001-04/msg00369.html (9,906 bytes)
- 255. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 17 Apr 2001 11:23:22 +0100
- Assuming that the arc strikes extremely rapidly, the rise time is going to be of the order of RC, where R is the glitch resistor and C is the bypass capacitance. That comes out to a few tens of nanos
- /archives//html/Amps/2001-04/msg00387.html (10,190 bytes)
- 256. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 17 Apr 2001 14:31:55 +0100
- Never tried to measure it. Whole earwigs can crawl past the edge of the blower wheel, but craneflies are reduced to decimal fractions. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' co
- /archives//html/Amps/2001-04/msg00392.html (9,272 bytes)
- 257. [AMPS] Zener screen supplies (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Tue, 17 Apr 2001 21:16:48 +0100
- She's a softie. The other 55 million of us can do much worse than her... if sufficiently provoked. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www
- /archives//html/Amps/2001-04/msg00403.html (9,437 bytes)
- 258. [AMPS] RF deck cooling (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sat, 21 Apr 2001 16:45:49 +0100
- Blowing into the output compartment is standard practice on many VHF/UHF cavity amps that use "external anode" tubes - but not quite in the way you were thinking of doing it. If you can totally seal
- /archives//html/Amps/2001-04/msg00453.html (9,088 bytes)
- 259. [AMPS] (no subject) (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sat, 10 Mar 2001 00:09:15 +0000
- The power output capabilities are actually very similar - as you'd expect because they are both 1.5kW dissipation tubes. The filament voltage, bias voltage, cathode impedance and drive requirements a
- /archives//html/Amps/2001-03/msg00063.html (8,128 bytes)
- 260. [AMPS] Meter Protection for Drake L7 (score: 147)
- Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
- Date: Sat, 10 Mar 2001 21:17:50 +0000
- You're asking for two different things: protection against faults, and low errors due to current flowing through the diode in normal operation. Both depend on the voltage drops across the individual
- /archives//html/Amps/2001-03/msg00074.html (9,088 bytes)
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