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161. Re: [Amps] 8877 filament. (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Thu, 4 May 2017 18:34:34 -0400
That scheme was tried in TV's and consumer radios in the 60's and 70's and called an instant on feature. The series string filaments were run through a diode when the set was "off" and the diode sho
/archives//html/Amps/2017-05/msg00057.html (8,227 bytes)

162. Re: [Amps] PL172 (8295) (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 6 May 2017 10:57:17 -0400
For the last 37 years my Hallicrafter HT33A has been sitting on the floor in the garage with an 8295A (Ceramic) fitted. I have a pair of 'new in the box' PL172s one of whose boxes is still sealed. P
/archives//html/Amps/2017-05/msg00082.html (8,072 bytes)

163. Re: [Amps] HV MOSFETs for RF (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 8 May 2017 07:14:48 -0400
Does anyone outside of ham radio care about modulation modes that require excellent linearity? 73, Cathy N5WVR AM and TV broadcasting, (analog and digital) except for the studio to transmitter link a
/archives//html/Amps/2017-05/msg00094.html (9,096 bytes)

164. Re: [Amps] Why a voltage doubler ? (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 13 May 2017 17:00:58 -0400
Why did early amplifiers use voltage doublers rather than twice the secondary turns and a full wave bridge? I think it is for two reasons, to control the impedance of the power supply and to limit th
/archives//html/Amps/2017-05/msg00129.html (8,625 bytes)

165. Re: [Amps] new amp race (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sun, 21 May 2017 19:20:13 -0400
It's an old adage but true: Most man made noise is vertically polarized because of the "shorting" effect of the earth. As a result if one is having trouble with man made noise, going to a horizontal
/archives//html/Amps/2017-05/msg00228.html (9,842 bytes)

166. Re: [Amps] Henry 3 KD Premier with 8877 (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 22 May 2017 17:50:52 -0400
Does anyone have any first hand experience with this amplifier? Im particularly interested in the 10 meter performance (Eb, Ib, Pi, Po). Maximum power output at .9A of Ib is only 1200 watts with eff
/archives//html/Amps/2017-05/msg00250.html (8,922 bytes)

167. Re: [Amps] LDMOS availability (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 10 Jun 2017 07:54:03 -0400
/* snip */ out in QST, its function was to cut off idle current between dots and dashes for qsk cw. /* snip */ I did this in 1973, I had to because of the electron noise from the two 6146s in my Heat
/archives//html/Amps/2017-06/msg00133.html (9,054 bytes)

168. Re: [Amps] About LP100A (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 19 Jun 2017 21:10:56 -0400
/* snip */ No digital scope is needed. I have other 'scopes for lab work. The LP500/LP700 has all the capability needed (and then some) for a monitor 'scope. The list of features is long, and geared
/archives//html/Amps/2017-06/msg00238.html (9,579 bytes)

169. Re: [Amps] About LP100A (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 19 Jun 2017 23:03:03 -0400
-- ORIGINAL MESSAGE --(may be snipped) Now that digital scopes are common, nothing else seem to exist. It looks like the lessons of history will be lost on this next generation. REPLY: Are you sayin
/archives//html/Amps/2017-06/msg00240.html (9,721 bytes)

170. Re: [Amps] About LP100A (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Tue, 20 Jun 2017 18:53:13 -0400
-- ORIGINAL MESSAGE --(may be snipped) Can a digital scope do Lissajous figures? REPLY: You might have me there, although with the built in measurement capabilities, Lissajous figures are no longer
/archives//html/Amps/2017-06/msg00250.html (9,453 bytes)

171. [Amps] I am just wondering ... (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Tue, 27 Jun 2017 10:34:40 -0400
Hi all: Have you ever hear of a HAM amplifier that feeds the reverse power (reflected power) value back to the exciter through the ALC signal to lower the drive under high reverse power conditions li
/archives//html/Amps/2017-06/msg00286.html (6,718 bytes)

172. [Amps] I am just wondering ... (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Tue, 27 Jun 2017 16:19:32 -0400
Hi all: Have you ever heard of a HAM amplifier that feeds the reverse power (reflected power) value back to the exciter through the ALC signal to lower the drive under high reverse power conditions l
/archives//html/Amps/2017-06/msg00289.html (7,968 bytes)

173. Re: [Amps] SB220 step start blows fuses (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Tue, 4 Jul 2017 17:51:02 -0400
Thank you for the replies. I had some time to circle back to this today and checked a few things. - With the tubes removed, it looks like they have no shorts but the grids measure ~0 ohms (maybe its
/archives//html/Amps/2017-07/msg00001.html (10,979 bytes)

174. Re: [Amps] Solder in pins for fabrication of A 3CX800A7 socket (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Wed, 5 Jul 2017 10:23:48 -0400
I On it's way to me from a faraway land is a PCB that is designed to be part of a socket for a 3CX800. It has 2.5mm clearance plated through holes. I need some solder in pins to make it into a workin
/archives//html/Amps/2017-07/msg00011.html (8,668 bytes)

175. Re: [Amps] SB220 step start blows fuses (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 10 Jul 2017 10:49:34 -0400
If you were to use this light bulb current limiter safety thing, but on a 220 variac, I assume you would have to put a light into each leg true? No, not at all, being a 220 Volt device neutral is unk
/archives//html/Amps/2017-07/msg00048.html (9,489 bytes)

176. Re: [Amps] TL922 problem (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sun, 3 Sep 2017 18:23:15 -0400
I have a TL922 that has a severe distortion problem - ONLY on the 80m band. At full power into a perfectly matched antenna, transmission starts off quite normal but quickly gets a raspy edge on it a
/archives//html/Amps/2017-09/msg00004.html (8,867 bytes)

177. Re: [Amps] Apparent Arcing (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Mon, 4 Sep 2017 18:27:50 -0400
I recently 'completed' a new amplifier. Everything seemed fine and I was quite happy. But I was only checking the transmit functions. However: I now find that when I power on the HV I get rf noise i
/archives//html/Amps/2017-09/msg00013.html (10,477 bytes)

178. Re: [Amps] SB200 on 30 M (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Fri, 6 Oct 2017 11:43:01 -0400
I don't know the rules in Canada, but 30 meters is a shared allocation and in the U.S. the power limit is 200 watts PEP. 300 watts on 30 meters is illegal in the U.S. Check your local regulations. T
/archives//html/Amps/2017-10/msg00077.html (7,693 bytes)

179. Re: [Amps] Pole pigs removed from oil ?? (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sat, 4 Nov 2017 11:48:43 -0400
I'm a little concerned about people just dumping the oil. Transformer oil is a famous source of PCB's. How old does a pole pig have to be before you can safely say there are no PCB's in the oil? 197
/archives//html/Amps/2017-11/msg00015.html (8,850 bytes)

180. Re: [Amps] Pole pigs removed from oil ?? (score: 1)
Author: Ron Youvan <ka4inm@gmail.com>
Date: Sun, 5 Nov 2017 22:58:41 -0500
If it smells like oil, it is oil!  If it doesn't, then it's probably PCB, except for some of the really new stuff and you are unlikely to run across any of that in retired pole pigs. It has been a ve
/archives//html/Amps/2017-11/msg00025.html (10,276 bytes)

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