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References: [ +from:vic@rakefet.com: 418 ]

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281. Re: [Amps] High SWR (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 21 Nov 2008 11:33:25 -0800
You don't say what kind of Alpha it is, but as far as I know they all have tuned inputs which should provide a good match to the exciter unless something is wrong. You should not need a tuner or any
/archives//html/Amps/2008-11/msg00215.html (7,833 bytes)

282. Re: [Amps] Pi-Net tank bandswitch question (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Fri, 28 Nov 2008 06:33:18 -0800
Possibly a better way would be to put a small inductance between the plate and the pi-net. It won't have much effect on the lower bands but will form an L network to raise the impedance seen by the t
/archives//html/Amps/2008-11/msg00242.html (7,017 bytes)

283. Re: [Amps] Vacuum Relay Issues (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 01 Dec 2008 09:48:08 -0800
Hi Tom, They always seem to fail this way. You should (probably already have?) checked for hot-switching. Make sure the time between the amp-out signal from the exciters and the onset of RF is long e
/archives//html/Amps/2008-12/msg00011.html (8,521 bytes)

284. Re: [Amps] Plate choke resonanse and safe operation (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 07 Dec 2008 08:21:28 -0800
You didn't mention it, but I assume that you know that the choke must be *shorted* when you dip it. I am afraid that the symptoms are mostly that the choke burns out! -- 73, Vic, K2VCO Fresno CA http
/archives//html/Amps/2008-12/msg00142.html (9,566 bytes)

285. Re: [Amps] Plate choke resonanse and safe operation (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 07 Dec 2008 13:47:35 -0800
I mean that in order to check for series resonance in the choke -- that's the kind that's dangerous -- you need to short-circuit the choke with a length of wire before measuring with the dip meter. O
/archives//html/Amps/2008-12/msg00154.html (9,857 bytes)

286. [Amps] 3-500z ratings (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Mon, 19 Jan 2009 15:43:13 -0800
The Eimac data sheet for the 3-500z <http://home.c2i.net/clank/ham/pa/3-500z.html> says that maximum plate current is 400 MA. This implies that exceeding this would be bad for the tube. But...if the
/archives//html/Amps/2009-01/msg00176.html (6,720 bytes)

287. Re: [Amps] Crydom Solid State Relays (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Wed, 28 Jan 2009 18:54:01 -0800
I used a solid-state relay in the primary of an 800-watt amplifier. When I operated on 80/160 with an inverted L antenna that put a reasonable amount of RF into the shack, I found that the relays wer
/archives//html/Amps/2009-01/msg00338.html (7,927 bytes)

288. Re: [Amps] Plate Choke Values (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Thu, 05 Feb 2009 09:10:33 -0800
This is a good question which I would like to know the answer to as well. My SB1000 makes less power on 160 than 80 or 40 meters; I am wondering if the choke is adequate. Some years ago I had an olde
/archives//html/Amps/2009-02/msg00115.html (9,045 bytes)

289. Re: [Amps] Nichrome wire for suppressors (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 10 Feb 2009 20:15:16 -0800
Sure. The use of nichrome wire in VHF parasitic suppressors is controversial. A very good explanation of VHF stability in vacuum tube amplifiers which argues *against* the use of nichrome wire can be
/archives//html/Amps/2009-02/msg00296.html (8,887 bytes)

290. Re: [Amps] Nichrome wire for suppressors (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 10 Feb 2009 20:22:42 -0800
Not fair! You left out the disclaimer "personally, I think..." and the references. He should read them and make up his mind. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _____________________
/archives//html/Amps/2009-02/msg00298.html (8,219 bytes)

291. [Amps] Quieting SB-1000 (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Feb 2009 07:33:23 -0800
In my quest for a quiet SB-1000, I replaced the fan. The original is a Nidac TA450AC, which is rated at 68 cfm and operates on 120vac. I replaced it with an ADDA AD1212LB3GL-LF which I got from Mouse
/archives//html/Amps/2009-02/msg00470.html (7,597 bytes)

292. Re: [Amps] Quieting SB-1000 (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Feb 2009 08:34:40 -0800
Getting a good shot at the screws is hard, thanks to the filament and plate chokes. I think I had an easier time than you...the screws were not that tight to begin with so the old one came out easily
/archives//html/Amps/2009-02/msg00474.html (8,708 bytes)

293. Re: [Amps] MFJ Analyzer for adjusting matching network... (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 21 Feb 2009 07:46:23 -0800
Make sure they are *really* low-inductance. Many modern film-type resistors are made by cutting a spiral groove in a conductive film. Old-style carbon resistors are good, but they tend to change valu
/archives//html/Amps/2009-02/msg00610.html (7,297 bytes)

294. Re: [Amps] caps across rectifier diodes (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 03 Mar 2009 08:35:35 -0800
Here's the complete explanation in that thread from W8JI, who designed the AL80A and the SB-1000 (which I have and which has capacitors across 1N5408's): -- "1.) The diode is a non-linear component w
/archives//html/Amps/2009-03/msg00101.html (10,116 bytes)

295. Re: [Amps] Remote QSK (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Wed, 04 Mar 2009 17:32:45 -0800
I did this with the Rich Measures circuit. I put a vacuum relay in one small aluminum box and reed relay in another. A third box contained the power supply, transistor switch, etc. The relay boxes ca
/archives//html/Amps/2009-03/msg00121.html (7,593 bytes)

296. Re: [Amps] SB-1000 - 100ma minimum plate current. (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 10 Mar 2009 07:58:08 -0700
This refers to the plate current with ZERO drive, the STBY/OPR switch in the OPR position and the RELAY connector on the back shorted to ground. You can check this without an exciter connected. Proba
/archives//html/Amps/2009-03/msg00274.html (8,306 bytes)

297. Re: [Amps] SB-1000 (Tom Mandera (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 10 Mar 2009 12:29:43 -0700
The SB-1000 does not have this. The interlock cuts the power, but doesn't short the HV. One should be *very* careful to discharge filter caps when working on it! -- 73, Vic, K2VCO Fresno CA http://ww
/archives//html/Amps/2009-03/msg00296.html (7,392 bytes)

298. Re: [Amps] Filament transformer question (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Wed, 11 Mar 2009 16:40:29 -0700
The 813 requires 5-0-5. The 10v total is applied to the filaments and the CT goes to the bias. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Amp
/archives//html/Amps/2009-03/msg00330.html (7,100 bytes)

299. Re: [Amps] tank calculations - MFJ analizer - resistor (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Tue, 21 Apr 2009 09:01:15 -0700
Leave the tube in (no plate voltage, of course). Otherwise the output capacity, which becomes part of the tune c, isn't there. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___________________
/archives//html/Amps/2009-04/msg00179.html (7,954 bytes)

300. Re: [Amps] Sleeve Baluns FS (score: 1)
Author: Vic K2VCO <vic@rakefet.com>
Date: Sat, 25 Apr 2009 12:04:53 -0700
Jim, I think you missed the statement that the cores are 1-1/8" long. This makes them equivalent to several of the usual "lifesaver-shaped" ones. The effect is proportional to the total length, not t
/archives//html/Amps/2009-04/msg00351.html (7,981 bytes)

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