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361. Re: [Amps] "Booster help" (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Sat, 11 Nov 2006 22:36:05 -0500
An easy to step the power up to a useable amount would be to build a very simple grounded grid amplifier. Oddly enough a grounded grid 6AG7 with 500 to 600 volts on the plate would give you a power g
/archives//html/Amps/2006-11/msg00153.html (9,246 bytes)

362. Re: [Amps] Class A for AM (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Wed, 15 Nov 2006 01:16:37 -0500
I have wondered about that. There may be some improvement. During the time that the single ended amplifier is approaching cutoff there is considerable non-linearity. In a AB push-pull amplifier both
/archives//html/Amps/2006-11/msg00189.html (10,282 bytes)

363. Re: [Amps] Class A for AM (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Wed, 15 Nov 2006 02:15:10 -0500
"We were chatting about a circa 1970 screen-modulated AM rig. Those things are also "efficiency-modulated" and so operate at about the same efficiency as a pure linear amplifier." Control grid modula
/archives//html/Amps/2006-11/msg00190.html (9,547 bytes)

364. [Amps] Screen grid modulation (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Wed, 15 Nov 2006 18:01:10 -0500
Just got home and turned on the computer. See lots of emails and have not gotten around to looking at them yet. But it occurred to me this morning that I had made an error. The screen grid modulated
/archives//html/Amps/2006-11/msg00207.html (8,337 bytes)

365. Re: [Amps] Russian power L-coupler (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 17 Nov 2006 12:21:35 -0500
I wonder how bad the varicouplers really are. The they often don't have a rolling or rubbing contact like roller inductors because a piece of very flexible wire can be used. Also, you can go from max
/archives//html/Amps/2006-11/msg00219.html (8,890 bytes)

366. Re: [Amps] Russian power L-coupler (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 17 Nov 2006 15:32:28 -0500
Sorry I meant 180 degrees. The point is if it is used in an application where a high Q is not needed there would be no problem because the circulating currents would not be high. Often they were used
/archives//html/Amps/2006-11/msg00224.html (10,883 bytes)

367. Re: [Amps] Russian power L-coupler (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 17 Nov 2006 17:08:39 -0500
You are assuming the Varicoupler is supposed to cover say .5uH to 80uH. Which is not its usual application. It is often use to fill in the gaps between taps on larger coils. Also, as I said in a L-Ne
/archives//html/Amps/2006-11/msg00227.html (8,719 bytes)

368. [Amps] QST (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Mon, 18 Dec 2006 11:42:40 -0500
I am becoming more and more disgusted with the lack of technical knowledge QST authors. A fine example is the article about reviving old linear amplifiers in the most recent QST. There is a schematic
/archives//html/Amps/2006-12/msg00136.html (7,206 bytes)

369. Re: [Amps] swr (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Thu, 04 Jan 2007 17:05:49 -0500
Many people just see the capacitance per unit length but don't realize it also has inductance per unit length. And the square root of the inductance divided by the capacitance per unit length is the
/archives//html/Amps/2007-01/msg00061.html (8,710 bytes)

370. Re: [Amps] schamatis 160 meter amp using 3cx3000a7 (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 12 Jan 2007 15:59:13 -0500
Sounds like CB jargon to me. In my 45 years I never heard hams use terms like that. I guess I have a three-by-two hundred sitting in my basement. 73 Bill wa4lav ______________________________________
/archives//html/Amps/2007-01/msg00096.html (11,344 bytes)

371. Re: [Amps] 3CV1500A7 (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Tue, 06 Feb 2007 10:47:39 -0500
Somewhere I have a very unusual 8877. It has no fins. It came in a surplus pulsed RF amplifier used in a MRI system. The anode fit directly into the tuned plate line (pipe) and some air was blown dow
/archives//html/Amps/2007-02/msg00076.html (10,300 bytes)

372. Re: [Amps] Thoriated tungsten lifetime when idling tspa (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 09 Feb 2007 16:32:27 -0500
There may be some truth to this because the filament emission loss is related to the filament temperature and the amount of time that it is hot, with or with out anode voltage. Running the filament c
/archives//html/Amps/2007-02/msg00169.html (7,606 bytes)

373. Re: [Amps] Getting rid of blower noise (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Tue, 20 Feb 2007 13:29:45 -0500
Unlike the situation where you are trying to null out the noise in a small confined environment such as a ear phone, the noise sources in the amplifier and the possible locations of reception of the
/archives//html/Amps/2007-02/msg00317.html (9,344 bytes)

374. Re: [Amps] Info On 4-1000A Availability...? (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Wed, 21 Feb 2007 13:35:05 -0500
I think Amperex (Covimag) is the only manufacturer that is now making 4-1000A tubes. Eimac sold that line off to Triton but they could get them right and quit making them. However, there are some gas
/archives//html/Amps/2007-02/msg00348.html (8,815 bytes)

375. Re: [Amps] B&W FC-30 Filament Choke: EPILOGUE (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Mon, 05 Mar 2007 10:39:23 -0500
I have some OLD FC-30 chokes in metal boxes with 4 terminals on each end. One had a bad internal connection so I pried open the box and found that it was made of ferrite or powdered iron toroids not
/archives//html/Amps/2007-03/msg00066.html (11,444 bytes)

376. Re: [Amps] GG Push-pull Amplifier (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 23 Mar 2007 10:32:46 -0400
That was 3 months ago. One problem with the multi-band tuner is that you have to make sure that when you are tuned to one of the lower frequency bands the high frequency components are also not produ
/archives//html/Amps/2007-03/msg00317.html (8,000 bytes)

377. [Amps] 30S1 Collins amplifier (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Sun, 08 Apr 2007 14:25:54 -0400
Now that I am the proud owner of a 30S1 I need some help from those that have had extensive experience working on them. Particularly how to get to nearly inaccessable parts on the "shelf". Is there a
/archives//html/Amps/2007-04/msg00034.html (6,672 bytes)

378. [Amps] 30S1 (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Wed, 11 Apr 2007 08:48:49 -0400
I recently acquired a Collins 30S1 amplifier. I am very impressed by its design and performance. It exceeded my expectations due to the fact that the only information I had was the spec sheets which
/archives//html/Amps/2007-04/msg00078.html (7,208 bytes)

379. Re: [Amps] 30S1 (score: 1)
Author: "Bill L. Fuqua" <wlfuqu00@uky.edu>
Date: Wed, 11 Apr 2007 23:30:36 -0400
I only got one response about the 30S1 amplifier. I was very lucky to get one at an university auction for a very low price. What in particular about some commercially produced amplifiers do some of
/archives//html/Amps/2007-04/msg00084.html (9,344 bytes)

380. Re: [Amps] My 813GG amp works (score: 1)
Author: Bill Fuqua <wlfuqu00@uky.edu>
Date: Mon, 30 Apr 2007 16:07:29 -0400
My first QRO amplifier was a pair of 813's that I built as a teenager. I got a transmitter at HS electronics in Miami. It came with a lot of spare tubes and loads of parts. Also had a 811 modulator a
/archives//html/Amps/2007-04/msg00382.html (10,195 bytes)


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