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Total 245 documents matching your query.

201. Re: [Amps] 3CX800 - a science experiment (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 1 Jun 2019 11:23:34 -0400
As I have previously mentioned, I have two Alpha 3CX800A7LG's that appear to have grid-cathode shorts that develop within a few minutes of applying filament voltage. After seeing VE5RA's posting abou
/archives//html/Amps/2019-06/msg00004.html (9,393 bytes)

202. Re: [Amps] Nylon in RF Tank Circuits (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sun, 9 Jun 2019 23:56:16 -0400
For decades Ive avoided using nylon hardware in the vicinity of an RF tank circuit because I believed nylon was prone to absorbing RF and burning. I dont know how or when I came to learn this inform
/archives//html/Amps/2019-06/msg00023.html (9,122 bytes)

203. Re: [Amps] Failure of a pair of FU728F (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sun, 15 Sep 2019 13:36:28 -0400
A friend asked to me why the pair of almost new FU728F tubes on its commercial PA goes south. It seems that, when tubes are warm, there is a short between Grid1 and Cathode on both tubes and, when th
/archives//html/Amps/2019-09/msg00023.html (8,358 bytes)

204. Re: [Amps] Failure of a pair of FU728F (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Fri, 20 Sep 2019 10:36:13 -0400
I believe that the tuning of a tetrode is different than a triode - correct?  Are they tetrodes less reliable or more finicky? Tetrodes, if operated properly are a rugged as a tetrode, but they are m
/archives//html/Amps/2019-09/msg00043.html (8,728 bytes)

205. Re: [Amps] Henry 3K-A choke failure...workaround? (score: 1)
Author: Ron <ka4inm@gmail.com>
Date: Thu, 26 Sep 2019 22:59:31 -0400
Hello wise ones... Bought a nice 3K-A at a flea market and made one SSB contact. On the second contact it tripped off on HV overcurrent. After some debugging, the Plate choke is leaky to ground at H
/archives//html/Amps/2019-09/msg00072.html (8,483 bytes)

206. Re: [Amps] Coolant for liquid-cooled solid-state amp (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Tue, 8 Oct 2019 16:37:24 -0400
Plain ol' distilled water will remove heat a lot better than diluting it with glycol, however the chemistry may dictate using it. De ionized water is much more corrosive than distilled even if it st
/archives//html/Amps/2019-10/msg00033.html (8,775 bytes)

207. Re: [Amps] shorted 3-500 (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 12 Oct 2019 14:16:33 -0400
Does anyone have a restoration technique to remove a grid cathode short on a 3-500Z? I have on just laying here--don't know why I keep it.  Filament still lights.  No plate to anything short. Can you
/archives//html/Amps/2019-10/msg00054.html (7,380 bytes)

208. Re: [Amps] SB-220 HV Transformer Wanted ; thread stolen for bias question (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Fri, 1 Nov 2019 06:45:49 -0400
First let's define classes of operation: Class A, plate current flows over 100% of the cycle of the input signal. Class B, plate current flows over exactly only 50% of the cycle of the input. ** Cla
/archives//html/Amps/2019-11/msg00002.html (10,904 bytes)

209. Re: [Amps] SB-220 HV Transformer Wanted ; thread stolen for (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Fri, 1 Nov 2019 14:04:59 -0400
RF linear amp....using tubes ?? I saw one when I was a kid, and it was not linear. 2 x tubes in P-P is a complex mess for RF HF freqs..esp multi band. They draw lots idle current. Same 2 x tubes in
/archives//html/Amps/2019-11/msg00010.html (10,599 bytes)

210. Re: [Amps] Quieting a Henry 2K Classic X (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Fri, 1 Nov 2019 14:34:11 -0400
I have acquired a Henry 2K Classic X (domestic model) amplifier. It uses a pair of 3-500Z's with chimneys. The very loud Dayton blower is driving me nuts. The Dayton blower is a model 2C915A, 3020 R
/archives//html/Amps/2019-11/msg00012.html (8,163 bytes)

211. Re: [Amps] 3CX3000A7 on 144 MHz (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Fri, 7 Feb 2020 15:45:54 -0500
Seems to me this problem may not be so troublesome. The dc resistance of the hot filament is 7.5V/51A=0.15 ohms. If the B- return is on one side of the filament, and if we assume the plate current i
/archives//html/Amps/2020-02/msg00073.html (9,068 bytes)

212. Re: [Amps] 3CX3000A7 on 144 MHz (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Fri, 7 Feb 2020 20:25:03 -0500
unbalanced CT,  but  have  forgotten  the tech  explanation.   Does anybody  remember ??? Yep, with directly heated cathodes it causes a change in K to G bias. -- Ron W4BIN - Understanding is much be
/archives//html/Amps/2020-02/msg00077.html (8,598 bytes)

213. Re: [Amps] Push pull amps (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Sat, 1 Aug 2020 21:08:22 -0400
I recently purchased some QST's from '47, 49, and 50. I notice a lot of transmitters and amps back then used 2 tubes in push-pull circuits, instead of parallel, like we mostly do now. What was the i
/archives//html/Amps/2020-08/msg00009.html (8,163 bytes)

214. [Amps] Really fancy Eimac tube (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Fri, 4 Dec 2020 07:27:45 -0500
Looks like a prototype for a 4-400A. For that kind of money a fellow could buy several 4-400As NOS that work. Ron W4BIN _______________________________________________ Amps mailing list Amps@contesti
/archives//html/Amps/2020-12/msg00002.html (6,574 bytes)

215. Re: [Amps] Looking for Alpha 87A expertise (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Sun, 14 Mar 2021 22:52:58 -0400
Doug ... How fast is a PIN diode?  How fast is a 1N4007 in an Alpha 87? If you have not measured their speed, how can you make that statement? It is my understanding that the 1N4007 (only) IS a PIN
/archives//html/Amps/2021-03/msg00010.html (8,371 bytes)

216. Re: [Amps] SB-220 (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Wed, 24 Mar 2021 14:10:44 -0400
I am assuming some of you here are also on the Heathkit HF Amps E -Mail list. So I won't go into the long drawn out story here unless asked to do so if needed. I re-built this old SB-220 practically
/archives//html/Amps/2021-03/msg00042.html (9,540 bytes)

217. Re: [Amps] Junk Connectors, Junk Coax (score: 1)
Author: W4BIN <ka4inm@gmail.com>
Date: Thu, 8 Apr 2021 21:01:30 -0400
same with stainless steel hardware!!! I'm working on HB AMP in garage and have magnet on work bench checking claimed SS washers / split washers are worst! very - very magnetic and junk as I see it (
/archives//html/Amps/2021-04/msg00035.html (9,337 bytes)

218. Re: [Amps] Alpha 87A Won't Transmit (score: 1)
Author: Ron W4BIN Youvan <ka4inm@gmail.com>
Date: Fri, 9 Apr 2021 11:19:12 -0400
about decade ago, read about method used at K3LR started doing it LR way Works! http://www.k3lr.com/engineering/pl259/ This method is the wrong method. As recommend by the ARRL and others, It is bes
/archives//html/Amps/2021-04/msg00048.html (10,944 bytes)

219. Re: [Amps] AL-811 Tube Swap (score: 1)
Author: W4BIN <ka4inm@gmail.com>
Date: Thu, 29 Apr 2021 12:19:09 -0400
Could the graphite plate of a 572B transform from a solid to a gas by sublimation? I know that carbon has three allotropes, but none are gaseous. If heat could cause carbon to become gaseous it woul
/archives//html/Amps/2021-04/msg00107.html (8,972 bytes)

220. Re: [Amps] HF 30 dB Coupler (score: 1)
Author: Ron W4BIN <ka4inm@gmail.com>
Date: Tue, 15 Jun 2021 11:05:34 -0400
Looking for an HF (3-30 MHz) Coupler for rf measurements. HB or commercial will do. Accuracy is not important but flatness would be a concern. 30dB port would do. Any suggestions ? With this kind of
/archives//html/Amps/2021-06/msg00004.html (8,389 bytes)

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