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Total 327 documents matching your query.

181. [Amps] FS: Amplifier Manuals (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Fri, 31 Mar 2017 13:20:09 -0600
I'm thinning out some files and have a few original amplifier manuals I'd like to unload: Price is $15 each, including shipping, CONUS only. PayPal only. 1, Alpha 77D/77S. Original operating and tech
/archives//html/Amps/2017-03/msg00155.html (6,981 bytes)

182. [Amps] Re FS: Amplifier Manuals (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Sat, 1 Apr 2017 10:19:05 -0600
Items 1, 2 and 4, below, have been sold. Items 3 and 5 still for sale. Jim W8ZR --Original Message-- From: Jim Garland Sent: Friday, March 31, 2017 2:20 PM To: Amps group Subject: [Amps] FS: Amplifie
/archives//html/Amps/2017-04/msg00003.html (7,442 bytes)

183. Re: [Amps] Tubes, transistors, and 'abuse' (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 11 Apr 2017 07:14:45 -0600
Anti-static maps are always a good idea, when working with solid state devices. I buy mine on eBay, and prefer the ones made by the Velleman because they have a nice white surface. They are not expen
/archives//html/Amps/2017-04/msg00062.html (7,453 bytes)

184. Re: [Amps] Tubes, transistors, and 'abuse' (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 11 Apr 2017 12:42:29 -0600
Ah, Wise move on your part, Manfred. I wouldn't wear it either! Your former boss needed higher level Technical Support! Jim Sent from my iPhone _______________________________________________ Amps ma
/archives//html/Amps/2017-04/msg00067.html (11,528 bytes)

185. Re: [Amps] Tubes, transistors, and 'abuse' (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 11 Apr 2017 12:52:00 -0600
Speaking of high resistance mats, an interesting property is that the resistance between any two points on the map is the same, no matter the distance between the points. In other words, it doesn't m
/archives//html/Amps/2017-04/msg00069.html (12,311 bytes)

186. Re: [Amps] Tubes, transistors, and 'abuse' (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Tue, 11 Apr 2017 14:17:04 -0600
Doug, I agree that those numbers sound low for an ESD mat, but I'm not surprised that the values of the two measurements were about the same. The thickness of the mat complicates the results when the
/archives//html/Amps/2017-04/msg00079.html (16,518 bytes)

187. Re: [Amps] Tubes, transistors, and 'abuse' (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 12 Apr 2017 10:50:32 -0600
You're partly right, Don, but only because a real mat always has some thickness and isn't always very large compared to the probe spacing. But even in that case, the difference in measurements isn't
/archives//html/Amps/2017-04/msg00095.html (19,876 bytes)

188. Re: [Amps] Entry level license (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 26 Apr 2017 12:14:42 -0600
Very thoughtful and measured analysis, Chris. One of my issues is that so many, possibly a majority, of new hams have no real interest in in the hobby but merely want transmitting privileges in conne
/archives//html/Amps/2017-04/msg00307.html (11,761 bytes)

189. [Amps] 8877 filament. (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 4 May 2017 12:21:09 -0600
The 8877 is a fabulous tube, but there are times when the warmup delay seems like an eternity. I wonder how much the warmup delay would be shortened if the filament was run at, say, 3 V on a 24/7 ba
/archives//html/Amps/2017-05/msg00054.html (7,236 bytes)

190. Re: [Amps] 8877 filament (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Fri, 5 May 2017 10:52:14 -0600
What is the mechanism by which an indirectly heated cathode is "poisoned" if the filament is run at a reduced voltage, with no other voltage on the tube? I know the cathode can be ruined if the tube
/archives//html/Amps/2017-05/msg00067.html (9,618 bytes)

191. Re: [Amps] Why a voltage doubler ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 13 May 2017 11:37:47 -0400
Simpler, cheaper transformer (no CT required, fewer turns), two diodes instead of four. Normally requires series, electrolytic caps, instead of single oil cap. Sent from my iPhone ___________________
/archives//html/Amps/2017-05/msg00125.html (7,372 bytes)

192. Re: [Amps] Why a voltage doubler ? (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sat, 13 May 2017 18:22:43 -0400
Seems to me the fault current would be determined by the capacitor bank value, not the transformer and rectifier configuration. I use a voltage doubler circuit in one of my homebrew amps, and it supp
/archives//html/Amps/2017-05/msg00131.html (10,426 bytes)

193. Re: [Amps] Henry 3 KD Premier with 8877 (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 22 May 2017 15:53:24 -0600
I'm not familiar with that particular amplifier, but low 10m efficiency is a common problem with 8877 amplifiers. In one of my homebrew amplifiers, I had low efficiency in the 40% range until, follow
/archives//html/Amps/2017-05/msg00251.html (9,333 bytes)

194. Re: [Amps] Tube amps are not a thing of the past (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 5 Jun 2017 10:02:36 -0600
I've long wondered what the zero watt rating of the 4cx1000 grid actually means. I've assumed it means the tube is rated for class AB1 operation only, and that the rating doesn't reflect the actual p
/archives//html/Amps/2017-06/msg00045.html (8,271 bytes)

195. Re: [Amps] 3-500Z cool down time (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 5 Jun 2017 12:39:26 -0600
Well, the plate is in a vacuum so no heat is conducted to the glass envelope except for the small plate lead pin. All the air in the world isn't going to cool the plate down. I think that's not quite
/archives//html/Amps/2017-06/msg00058.html (8,634 bytes)

196. Re: [Amps] LDMOS availability (score: 1)
Author: Jim Garland <4cx250b@miamioh.edu>
Date: Fri, 9 Jun 2017 22:02:53 -0600
There are two issues, here, one being the definition of Class C, and the other being linearity. I'm inclined to agree with Bill on both. It's not hard to imagine modulating the bias, so that on voice
/archives//html/Amps/2017-06/msg00130.html (10,669 bytes)

197. Re: [Amps] About LP100A (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 18 Jun 2017 18:28:56 -0600
I have an LP100A wattmeter and like it very much. But how do any of you know how accurate it really is? The only way to know is with a calibration standard, and RF power is notoriously difficult to m
/archives//html/Amps/2017-06/msg00221.html (9,516 bytes)

198. Re: [Amps] About LP100A (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Mon, 19 Jun 2017 08:10:50 -0600
I used a Bird dummy load, rated to above 1 GHz. The Scope was a recently calibrated Tek 2465B. I'd estimate overall measurement accuracy to about 3%. 73, Jim w8zr Sent from my iPhone ________________
/archives//html/Amps/2017-06/msg00233.html (11,554 bytes)

199. Re: [Amps] About LP100A (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Tue, 20 Jun 2017 16:18:35 -0600
Manfred, my all-time favorite analog scope is the Tektronix 2465B, which has a 350 MHz BW. (other 2400 series scopes have the same features, but lower BW). To me, the 2465B represents the pinnacle of
/archives//html/Amps/2017-06/msg00247.html (9,367 bytes)

200. [Amps] Drake W4 meter (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Mon, 26 Jun 2017 11:26:50 -0600
My Drake W4 wattmeter fell off the table and broke the meter movement. The meter was made by Honeywell, with a 200uA movement. Anybody know where I can find one. I can reuse the case and scale, but n
/archives//html/Amps/2017-06/msg00277.html (6,323 bytes)

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