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241. [AMPS] FT100D driving Alpha 87a (score: 1)
Author: Peter.Chadwick@zarlink.com (Peter Chadwick)
Date: Fri, 27 Jul 2001 14:55:35 +0100
I suppose very occasionally it might be....it comes down to how well engineered the ALC is, and how much range it's supposed to have. As Rich says, too much mic gain can really lead to problems. I've
/archives//html/Amps/2001-07/msg00328.html (8,883 bytes)

242. Re: [Amps] X-TRA TUBE DAYS (score: 1)
Author: peter.chadwick@zarlink.com
Date: Fri, 12 Sep 2003 08:17:30 +0100
I don't disagree with David here at all, but I don't see the the problem being merely restricted to amateurs. It's getting much harder for the professional lab to prototype anything, too. OK, so we s
/archives//html/Amps/2003-09/msg00105.html (8,563 bytes)

243. Re: [Amps] Using surface-mount devices (score: 1)
Author: peter.chadwick@zarlink.com
Date: Mon, 15 Sep 2003 10:43:37 +0200
They're nothing - just wait until you get WSP (Wafer Scale Packaging). In that, you take the IC chip and put a layer of insulation over the top, with via holes to the pads. Then you metalise through
/archives//html/Amps/2003-09/msg00127.html (7,757 bytes)

244. Re: [Amps] Using surface-mount devices (score: 1)
Author: peter.chadwick@zarlink.com
Date: Mon, 15 Sep 2003 11:01:16 +0200
David said about RSGB Radcom down for being too technical. It's always been a bit of a problem with Radcom, and I guess, QST. Most hams these days aren't that interested in technical matters, while l
/archives//html/Amps/2003-09/msg00128.html (7,647 bytes)

245. Re: [Amps] Tufnol rod (score: 1)
Author: peter.chadwick@zarlink.com
Date: Mon, 15 Sep 2003 15:17:45 +0200
Tufnol is, as Steve says, a proprietary brand of SRBF (Synthetic Resin Bonded Fibre). However, it's also available in thin sheet form (1/32 and 1/64 inch thick) which I suspect is a somewhat differen
/archives//html/Amps/2003-09/msg00131.html (8,251 bytes)

246. Re: [Amps] Re: Using Surface-Mount Devices (score: 1)
Author: peter.chadwick@zarlink.com
Date: Tue, 16 Sep 2003 17:26:28 +0200
We're using 10 mil (.25mm) spacing on a 40 'pin' WSP package. Not my choice, but there..... I'm beginning to think that moving to octal tube sockets was pushing it a bit far! 73 Peter G3RZP _________
/archives//html/Amps/2003-09/msg00141.html (7,179 bytes)

247. [Amps] Old tubes (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 15 Oct 2003 11:28:12 +0200
I still see a fair number of older tubes of the 826,829, 832 variety being sold, as well as 5894s and so on. Previous experience with the 826, 829 832 is that most of them are getting pretty old and
/archives//html/Amps/2003-10/msg00140.html (6,547 bytes)

248. Re: [Amps] Zener Diode needed (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Tue, 21 Oct 2003 14:15:20 +0100
By choosing the right voltage zeners, an almost zero temperature coefficient can be obtained, which cannot be done with diodes. 73 Peter G3RZP _______________________________________________ Amps mai
/archives//html/Amps/2003-10/msg00206.html (7,352 bytes)

249. Re: [Amps] Ameritron AL-572B (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Tue, 21 Oct 2003 14:25:39 +0100
against it. I've not found them very fragile, but I have found them prone to VHF parasitics because they have very long grid leads, and as a result, by the time you've cured the parasitics, they're n
/archives//html/Amps/2003-10/msg00207.html (8,009 bytes)

250. Re: [Amps] About single 4CX250b output power (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 5 Nov 2003 08:07:45 +0000
I feel that we should remember that the 'grandfather' of this series was the 4X150, which was a 1945/6 design, intended for Class C service, and the 4X250 followed a few years later. (My 1946 ARRL ha
/archives//html/Amps/2003-11/msg00057.html (8,875 bytes)

251. [Amps] Re:SB220 (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 5 Nov 2003 08:52:26 +0000
A bit off topic, but would anyone care to guess at how much it would cost to produce a SB220 kit now? Looking back through old magazines, I'm convinced that ham radio ahs never been as cheap as it is
/archives//html/Amps/2003-11/msg00058.html (6,460 bytes)

252. Re: [Amps] 4CX1600B (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Tue, 11 Nov 2003 13:31:45 +0000
the contest season. As Rich Measures says, Murphy wins! It will ONLY fail during the contest - or the really big pile up for the DX country you need - especially if it's not been on for ten years and
/archives//html/Amps/2003-11/msg00149.html (7,184 bytes)

253. Re: [Amps] L-7 Failure, HV fuses (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 17 Nov 2003 08:54:34 +0000
30 gauge might be a bit on the thick side. I successfully use 40 SWG. 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/
/archives//html/Amps/2003-11/msg00226.html (7,380 bytes)

254. RE: [Amps] Benefits of 3-phase power? (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 17 Nov 2003 09:18:17 +0000
It's not usual to provide 3 phase mains in the UK to domestic premises. Some country areas have 2 phase - that's what I have. There's an 11kV 3 phase line to a transformer near the house, and the out
/archives//html/Amps/2003-11/msg00227.html (8,165 bytes)

255. Re: [Amps] Benefits of 3-phase power? (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 24 Nov 2003 08:44:33 +0000
As Roger must have found, they don't have very much real beer, either! 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com
/archives//html/Amps/2003-11/msg00341.html (8,006 bytes)

256. [Amps] Three phase (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 24 Nov 2003 08:50:06 +0000
Three phase is common industrially, although there are strict limitations where only one phase is being used as to how close you bring something run off another phase, in case of insulation failure.
/archives//html/Amps/2003-11/msg00342.html (6,918 bytes)

257. Re: [Amps] RE: High voltage D.C. transmission... (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 24 Nov 2003 09:03:00 +0000
I read that when the cross channel power link was first tried, it used AC, but the sea water led to large losses because of the dielectric's poor power factor - it apparently used two conductors. Thu
/archives//html/Amps/2003-11/msg00343.html (7,320 bytes)

258. Re: [Amps] AC or DC better for indirectly heated cathodes? (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Mon, 24 Nov 2003 09:12:07 +0000
This is my worry, too. In semiconductors, it's called 'metal migration', and it goes faster as the temperature goes up. For my 4CX1000, I'm using a constant current supply for the filament, set so th
/archives//html/Amps/2003-11/msg00344.html (8,822 bytes)

259. Re: [Amps] trouble with TT centurion (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Wed, 26 Nov 2003 10:26:34 +0000
Sounds a bit to me like there's RF getting back in somewhere. Common mode chokes on the coax and mains leads sound like a good start. 73 Peter G3RZP _______________________________________________ Am
/archives//html/Amps/2003-11/msg00369.html (7,071 bytes)

260. Re: [Amps] Really Big Solid State Power Amplifiers (score: 1)
Author: peter.chadwick@Zarlink.Com
Date: Fri, 19 Dec 2003 09:49:51 +0000
There can be major cost advantages to building tube amplifiers - it's easier to beg parts, as GW4DGU well knows - he gave me a vacuum variable and a 4CX1000! I still feel that a 4 tube 4CX250 HF amp
/archives//html/Amps/2003-12/msg00301.html (6,863 bytes)


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