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Total 406 documents matching your query.

201. Re: [Amps] THE SKINNY ON MY AL-82 (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Thu, 18 Dec 2014 17:10:53 +0200
What are the symptoms of an 'event'? On 18 Dec 2014 16:49, Bill and Liz wrote: I recently tracked down the ham who had done work on my AL-82 as well as a second one purchased at the same time by anot
/archives//html/Amps/2014-12/msg00065.html (8,570 bytes)

202. Re: [Amps] THE SKINNY ON MY AL-82 (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Sat, 20 Dec 2014 07:53:46 +0200
Nobody ever said that the object of a parasitic suppressor wasn't to lower the Q of the parasitic 'tank circuit'! But there's no advantage to reducing the Q of the coil in the suppressor, which was w
/archives//html/Amps/2014-12/msg00073.html (8,697 bytes)

203. Re: [Amps] AL-1200 (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Wed, 24 Dec 2014 20:23:09 +0200
Make sure the primary of the plate transformer is correctly wired for the line voltage. For example, if the transformer is wired for 220 and the line voltage is 250 (not uncommon), a nominal 3200V DC
/archives//html/Amps/2014-12/msg00092.html (8,444 bytes)

204. Re: [Amps] L4B biasing (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Thu, 25 Dec 2014 07:41:40 +0200
According to the 3-500z data sheet, this should be fine. The 200 ma seems a little low, but I guess it depends on the tubes. You should make sure that you can get rid of the heat. Vic K2VCO /4X6GP __
/archives//html/Amps/2014-12/msg00099.html (7,647 bytes)

205. Re: [Amps] The genius of ham radio (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Tue, 13 Jan 2015 07:11:56 +0200
Because it stores energy during the portion of the cycle that the tube is cut off. Vic K2VCO /4X6GP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.
/archives//html/Amps/2015-01/msg00069.html (15,926 bytes)

206. Re: [Amps] Vendor For Transformer Rewind (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Sat, 24 Jan 2015 18:31:35 +0200
But he should have them add a tap for 240, too. Vic K2VCO /4X6GP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amp
/archives//html/Amps/2015-01/msg00249.html (9,471 bytes)

207. Re: [Amps] Vendor For Transformer Rewind (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Sat, 24 Jan 2015 20:26:32 +0200
I see. I didn't understand. I thought you meant ONLY 208 and 220. My old QTH in Fresno was usually quite close to 240. Is there anywhere in the US that still has 120/240 volt power? 73, Martin W2RWJ
/archives//html/Amps/2015-01/msg00254.html (9,556 bytes)

208. Re: [Amps] push pull or parallel ? (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Tue, 27 Jan 2015 05:45:11 +0200
I think the plate impedance is higher for push-pull than parallel operation with the same voltage and average plate current (no time now to look it up), because the tubes conduct over different parts
/archives//html/Amps/2015-01/msg00315.html (12,006 bytes)

209. Re: [Amps] {Collins} Understanding Screen Current in a Tetrode (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Wed, 28 Jan 2015 08:29:45 +0200
Carl is correct. In the 4CX1000a the spec sheet calls for 35 ma screen current in typical AB1 service. The screen dissipation is 12w, and at the rated 325v, that would be 36 ma! Of course the duty cy
/archives//html/Amps/2015-01/msg00330.html (18,582 bytes)

210. Re: [Amps] {Collins} Understanding Screen Current in a Tetrode (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Wed, 28 Jan 2015 11:27:04 +0200
I don't know about 'knowledgeable', but screen current goes negative when more electrons are emitted from the screen than are captured by it. They go the plate. In a pentode, the interposed grounded
/archives//html/Amps/2015-01/msg00335.html (9,497 bytes)

211. Re: [Amps] Biasing a Class C modulated final (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Wed, 18 Feb 2015 11:09:42 +0200
I'm not sure what a 'pseudo zener' is, but it would need to dissipate about 45 W when transmitting to produce the portion of bias equal to cutoff, which is usually what the fixed bias supply does. An
/archives//html/Amps/2015-02/msg00107.html (10,723 bytes)

212. Re: [Amps] New Amplifier Problem (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Mon, 30 Mar 2015 10:56:46 +0300
An insect in the tuning capacitor? Used to fry mice regularly in the phaser at the AM BC station I worked at. Hi I just bought a new to me amplifier (Alpha 89) that I have run into a problem. I was t
/archives//html/Amps/2015-03/msg00081.html (8,462 bytes)

213. Re: [Amps] Yaesu FL2000B amp and input tuning problems (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Mon, 06 Apr 2015 12:59:12 +0300
I don't see why it shouldn't work, as long as you know the correct value of input impedance. It depends on the class of operation. The tubes must be in place when you do it, because the grid-cathode
/archives//html/Amps/2015-04/msg00044.html (11,331 bytes)

214. Re: [Amps] Tetrode calcs (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Mon, 27 Apr 2015 08:12:42 +0300
The Eimac datasheet has 500v on the screen for voltages between 2500 and 4000 in AB2. Maximum screen v is 600, so be careful. Vic 4X6GP/K2VCO _______________________________________________ Amps mail
/archives//html/Amps/2015-04/msg00168.html (7,245 bytes)

215. Re: [Amps] Time for New Power Meter (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Mon, 04 May 2015 20:14:13 +0300
When they suspected someone of cheating, they would park their van outside his house and measure field strength. Then they would go inside and measure plate voltage and current (I presume with their
/archives//html/Amps/2015-05/msg00056.html (10,800 bytes)

216. Re: [Amps] [Bulk] Re: Time for New Power Meter (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Mon, 04 May 2015 20:42:38 +0300
Here's some: <http://p1k.arrl.org/pubs_archive/56090> K6EVR had his license suspended for 'superpower'. QST Feb. 1969, p.63 <http://p1k.arrl.org/pubs_archive/53896> W6VSS suspended for "power in exce
/archives//html/Amps/2015-05/msg00058.html (13,398 bytes)

217. Re: [Amps] tetrode push-pull amp schematics (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Thu, 18 Jun 2015 09:45:24 +0300
The 4CX1500b is designed to be exceptionally clean in class AB1. I don't know if anything significant is to be gained by operating class A as a previous poster suggested. Unless you need a shack heat
/archives//html/Amps/2015-06/msg00055.html (12,851 bytes)

218. Re: [Amps] boost transformer (score: 1)
Author: Vic Rosenthal 4X6GP/K2VCO <k2vco.vic@gmail.com>
Date: Sat, 04 Jul 2015 09:31:42 +0300
It's kind of a stretch. I have done this, but never increased the line voltage more than 10% (on the grounds that most components have at least a 10% safety factor built in). But keep in mind that yo
/archives//html/Amps/2015-07/msg00011.html (7,950 bytes)

219. Re: [Amps] Another 50MHz oscillator (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Mon, 20 Jul 2015 18:30:00 +0300
It looks like a grid-driven push-pull amplifier. I don't see any evidence of a neutralization circuit, which certainly could explain the oscillations. It should be easy to add a traditional cross-neu
/archives//html/Amps/2015-07/msg00070.html (10,804 bytes)

220. Re: [Amps] Follow-up...re: Time to ask for help. (score: 1)
Author: Vic Rosenthal <k2vco.vic@gmail.com>
Date: Sun, 26 Jul 2015 22:31:16 +0300
Sounds like you are adding POSITIVE feedback, not negative! Look up 'bridge neutralization' in an ARRL or Bill Orr handbook. The grid side of the neutralizing capacitor goes to the bottom of the grid
/archives//html/Amps/2015-07/msg00145.html (9,760 bytes)


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