- 1. Re: [Amps] Centurion (Rob Atkinson) (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Fri, 29 May 2009 14:35:50 -0700
- Some time ago I researched the stock Centurion fan and a possible replacement. The stock is a Bisonic 4E-115B-25 115vac 21 watt. An exact physical replacement is Bisonic 4E-115B 115 vac 22 watt. I go
- /archives//html/Amps/2009-05/msg00261.html (7,931 bytes)
- 2. Re: [Amps] PTFE dielectricum variable cap (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Mon, 15 Mar 2010 17:08:44 -0700
- What I wonder about is having small air gaps at spots where the teflon sheet and the rotor/stator plates are bearing against the teflon. If the dielectric is uniform there is no problem but it seems
- /archives//html/Amps/2010-03/msg00287.html (12,690 bytes)
- 3. Re: [Amps] LCR meter & measuring components (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Wed, 31 Mar 2010 15:30:39 -0700
- FWIW - There is a pretty definitive method of measuring an inductor which will yield its low freq inductance , its self resonant frequency , and the distributed capacitance. It is normally done with
- /archives//html/Amps/2010-03/msg00977.html (9,868 bytes)
- 4. Re: [Amps] Centurion plate current issue (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Wed, 9 Jun 2010 17:53:42 -0700
- Gary - I agree with Carl - looking at the Eimac constant current curves - those tubes look fine. 175 ma at zero bias and about 3100 volts is what it ought to be. I still think you have a blown bias t
- /archives//html/Amps/2010-06/msg00102.html (10,019 bytes)
- 5. Re: [Amps] Tubes, made in the USA, in the olden days; Films? (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Mon, 30 Aug 2010 22:01:17 -0700
- I was asked to send this to the reflector so here 'tis. Maybe it will bring an old tube maker out of the woods to refresh my memory. Sometime in the late 50's or early 60's I was in a Ham club in Cin
- /archives//html/Amps/2010-08/msg00483.html (11,785 bytes)
- 6. Re: [Amps] Thp HL-2k (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Wed, 15 Sep 2010 13:37:10 -0700
- Are you sure the power peak is on 75 meters and not on 40 meters with the PA trying to double to 40 ? The plate tuning going to minimum capacitance is suspicious.(And I assume you really mean plate t
- /archives//html/Amps/2010-09/msg00193.html (9,455 bytes)
- 7. Re: [Amps] 4- 572's (score: 1)
- Author: pfizenmayer <pfizenmayer2@q.com>
- Date: Tue, 19 Oct 2010 22:18:19 -0700
- What is a rough number for resistive part of input of 4 GG 572'bs at 80- 40 meters ? Have a friend working on a 4 -572b amp that appears might have screwed up input networks and would like to look at
- /archives//html/Amps/2010-10/msg00319.html (7,048 bytes)
- 8. Re: [Amps] AL-572 Question (score: 1)
- Author: pfizenmayer <pfizenmayer2@q.com>
- Date: Sat, 23 Oct 2010 16:24:06 -0700
- Anyone know the Ameritron procedure for adjusting neutralization on an AL-572 - or for that matter any hints to check ? Have a friend with an AL872 that is pretty wild on 15 - will take off with cert
- /archives//html/Amps/2010-10/msg00359.html (7,904 bytes)
- 9. Re: [Amps] AL-572 Question (score: 1)
- Author: pfizenmayer <pfizenmayer2@q.com>
- Date: Sat, 23 Oct 2010 16:41:25 -0700
- I finally foud a note from Tom W8JI - I thought it could be done cold and he confirmed what I thought -Just wanted a second opinion besides mine ! Thanks anyhow -- Hank K7HP _________________________
- /archives//html/Amps/2010-10/msg00360.html (8,649 bytes)
- 10. Re: [Amps] Ameritron AL-572 (score: 1)
- Author: pfizenmayer <pfizenmayer2@q.com>
- Date: Sat, 6 Nov 2010 10:25:38 -0700
- I have been trying to help a fellow ham get an AL-572 tamed down via emails. He had a tube short/arc and blow one of the 50 ohms to ground grid resistors- the tubes were pretty old and tired anyhow s
- /archives//html/Amps/2010-11/msg00029.html (7,642 bytes)
- 11. Re: [Amps] brass or BNP hardware (score: 1)
- Author: pfizenmayer <pfizenmayer2@q.com>
- Date: Tue, 23 Nov 2010 10:01:15 -0700
- I can confirm what John K5PRO says - I worked at Gates Radio in the early 1960's in the AM broadcast section . If a piece of steel hardware got put in about anywhere in the RF areas of the 50 and 100
- /archives//html/Amps/2010-11/msg00394.html (14,012 bytes)
- 12. Re: [Amps] amp with push-pull output and magnetic coupling to theantenn (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Sat, 29 Jan 2011 16:13:23 -0700
- B&W actually had a swinging link version that had a 1/4 inch shaft connection to swing the link from the panel - and the swing arm also took a plug in link for various bands . The low freq link had t
- /archives//html/Amps/2011-01/msg00410.html (8,245 bytes)
- 13. Re: [Amps] 'heat spreader' sizing ?? (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Fri, 4 Feb 2011 19:00:29 -0700
- Like Roger , it has been years since I did this sort of work and even then there was a group that did most of our FEM for stuff like this and stress/strain analysis of composite structures. But one t
- /archives//html/Amps/2011-02/msg00024.html (9,778 bytes)
- 14. Re: [Amps] Al-82 Blowing fuses? (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Wed, 2 Mar 2011 14:00:21 -0700
- I would yield to the amp gurus - but I suspect the 10 to 25 ohm surge resistor between the filter cap bank and the tube will do more to protect the tube than any fuses . Hank K7HP ___________________
- /archives//html/Amps/2011-03/msg00027.html (9,219 bytes)
- 15. Re: [Amps] 4CX1500B project - swamped grid (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Thu, 9 Aug 2012 22:12:46 -0700
- I looked at 50 ohms shunted by 80 pfd -- 2 - 30 mhz - -- series L of 271 nhy and shunt C of 71.5 pfd at input gives better than 23 db return loss from 2 to 30 mhz. I was wondering why Alpha did not l
- /archives//html/Amps/2012-08/msg00162.html (11,457 bytes)
- 16. Re: [Amps] 4CX1500B project - swamped grid (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Fri, 10 Aug 2012 08:48:58 -0700
- Thought he was talking about no grid current - but even with grid current what other sort of input network would be any better over the swing with regard to match? I would think , without doing the d
- /archives//html/Amps/2012-08/msg00164.html (15,130 bytes)
- 17. Re: [Amps] 4CX1500B (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Fri, 10 Aug 2012 12:41:18 -0700
- Just for hell of it since I was set up -- I built that network in Genesys and let it optimize for what Rload and Cload was optimum 2 to 29.75 mHz. First looked at network using 50 ohms R load and let
- /archives//html/Amps/2012-08/msg00167.html (8,272 bytes)
- 18. [Amps] Blue Disc Ceramic caps ?? (score: 1)
- Author: "pfizenmayer" <pfizenmayer2@q.com>
- Date: Thu, 16 Aug 2012 13:38:00 -0700
- I see a proliferation of blue encased caps appearing to possibly be disc ceramics being used in RF applications. For instance the MFJ1500 watt autotuner , and Alpha is using them as padders . Does an
- /archives//html/Amps/2012-08/msg00257.html (6,515 bytes)
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