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Total 1396 documents matching your query.

241. [Amps] Any experiences with "powergridtube"? (YC156 hunt) (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 30 Sep 2010 23:39:17 -0700
Date: Thu, 30 Sep 2010 21:35:07 -0400 From: "Kevin Adam" <n9iww@msn.com> Subject: Re: [Amps] Any experiences with "powergridtube"? (YC156 hunt) To: <dezrat1242@yahoo.com>, "AMPS" <amps@contesting.com
/archives//html/Amps/2010-09/msg00377.html (10,927 bytes)

242. [Amps] Switching Supplies for High Current Filaments (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Tue, 5 Oct 2010 21:00:46 -0700
Are there any sensibly priced switching supplies (even surplus) that are small and light, that could power some of the QRO tubes with high current filaments? Would, say, a 5v, 30A switcher which cou
/archives//html/Amps/2010-10/msg00039.html (10,150 bytes)

243. [Amps] 833 plate cathode capacitance (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 6 Oct 2010 04:21:53 -0700
Finally got around to it and measured the plate to cathode capacitance. I was quite surprised. It was as high as stated in specs. I got about 20pF but that includes a few pF from setup wiring. I thou
/archives//html/Amps/2010-10/msg00043.html (7,803 bytes)

244. [Amps] Skin depth: silver plating of tank circuit coil (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 6 Oct 2010 04:56:34 -0700
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/msg00044.html (9,159 bytes)

245. Re: [Amps] Switching Supplies for High Current Filaments (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 6 Oct 2010 21:26:00 -0700
On tubes, it's even worse, typ 12%. On the few switcher's we experimented with.. all had a built in ramp up feature on start up. IE: with no load on the switcher's output, the output Vdc would ramp
/archives//html/Amps/2010-10/msg00071.html (16,023 bytes)

246. Re: [Amps] Switching Supplies for High Current Filaments (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 7 Oct 2010 03:00:00 -0700
a directly heated [thoriated tungsten] GG triode. However, ur scheme would work with directly heated tetrodes.... like a 4CX-5000. Jim VE7RF _______________________________________________ Amps maili
/archives//html/Amps/2010-10/msg00075.html (9,740 bytes)

247. [Amps] Switching Supplies for High Current Filaments (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 7 Oct 2010 05:41:05 -0700
_______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2010-10/msg00081.html (12,426 bytes)

248. [Amps] GRIPE! (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 8 Oct 2010 06:40:19 -0700
I wont look anymore,at least you see things like this stateside,they are like hens teeth and mega bucks here. And we all hear the stories of "picked one up at a rally" for like cheap. Regards Jon for
/archives//html/Amps/2010-10/msg00123.html (7,995 bytes)

249. [Amps] Autotuner for Amp Input (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 8 Oct 2010 08:35:59 -0700
You should be able to pick up a 23rd edition on Amazon.com. 73 Jim W7RY Most of em are typo's and stuff, so be careful. Some of it is silly stuff, like calling it C1 and C1, when they meant C1 and C2
/archives//html/Amps/2010-10/msg00125.html (12,278 bytes)

250. [Amps] Which LDG Autotuner for Amp Input? (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Sat, 9 Oct 2010 07:52:51 -0700
This isn't in any of the Handbooks I happen to own. I tried looking on LDG's web site but found no autotuner without a box. Maybe it is a special order item? Does anyone have more info on this? 2008
/archives//html/Amps/2010-10/msg00144.html (7,925 bytes)

251. [Amps] TUNER (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Mon, 11 Oct 2010 06:43:12 -0700
If you put the tuner at the back of the Amp..Why not just use the tuner in the Radio? Bob C2 cap of any PI tuned input. Those pulses are typ 3 times the plate current for AB-2... and 4 times the plat
/archives//html/Amps/2010-10/msg00177.html (8,401 bytes)

252. [Amps] TUNER (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Tue, 12 Oct 2010 23:19:25 -0700
I wonder how one of these tuners, or input boards would work with a passive grid input on a Tetrode. 73 Roger (K8RI) passive grid R or a 200 ohm resistor.....and a 4:1 un-un. On the big boy tubes [ha
/archives//html/Amps/2010-10/msg00215.html (7,825 bytes)

253. [Amps] cathode driven 4CX tubes. (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 13 Oct 2010 00:28:16 -0700
I was just looking at Bill Orr's article about super cathode driven tube amps in the July 67 QST. He has a example of a 4CX300A (control grid connected to cathode) cathode driven amplifier. It only h
/archives//html/Amps/2010-10/msg00216.html (8,317 bytes)

254. [Amps] 6146 via 572b's (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 13 Oct 2010 00:38:48 -0700
ORIGINAL MESSAGE: REPLY: Best idea yet. :-) 73, Bill W6WRT tough slog. I gave up on these 100w xcvr's yrs ago. My FT-1000-D does 300 w pep put, without breaking a sweat. I tried 10 watts QRP cw yrs a
/archives//html/Amps/2010-10/msg00217.html (8,292 bytes)

255. [Amps] TUNER (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 14 Oct 2010 02:30:33 -0700
EXCEPT when you get to the higher bands. (10 and 15. And sometimes 20). You need a way to cancel out the reactance. At least you do on a pair of 4CX800 Russian tetrodes. 73 Jim W7RY parallel with the
/archives//html/Amps/2010-10/msg00231.html (8,993 bytes)

256. [Amps] New 2 PA design (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Sun, 17 Oct 2010 00:42:15 -0700
I'm drifting off topic a little but is it not preferable for heat transfer purposes to run several lower power transistors in parallel to reduce hot spots? There is also the opportunity to have redun
/archives//html/Amps/2010-10/msg00270.html (9,870 bytes)

257. [Amps] diode junction temps and thermal resistance (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 20 Oct 2010 07:52:29 -0700
with 10 w zeners back in the 70's is..they are the 1st component to short out come glitch time. The problem with both a 10 w and a 50 w zener's is they won't handle a surge worth a damn. If you use a
/archives//html/Amps/2010-10/msg00328.html (13,489 bytes)

258. [Amps] Tubes , sockets, etc, for sale (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 21 Oct 2010 03:03:18 -0700
A fellow here in town has a bunch of tubes/sockets etc for sale, that he asked me to list for him. Contact me directly, if you are interested. - 5 x Eimac new and used 5CX-1500B -1 x used socket for
/archives//html/Amps/2010-10/msg00336.html (6,977 bytes)

259. [Amps] Fw: diode junction temps and thermal resistance (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 20 Oct 2010 13:41:41 -0700
Jim, in using the string of diodes for bias, do you notice any drift in the idle current as they warm up? Purchased in quantity these big diodes are way less expensive than a big zener diode and woul
/archives//html/Amps/2010-10/msg00337.html (15,214 bytes)

260. [Amps] Tubes , sockets, etc, for sale (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 21 Oct 2010 21:32:27 -0700
A fellow here in town has a bunch of tubes/sockets etc for sale, that he asked me to list for him. Contact me directly, if you are interested. - 5 x Eimac new and used 5CX-1500B -1 x used socket for
/archives//html/Amps/2010-10/msg00347.html (8,067 bytes)

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