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21. Re: [Amps] Real power from GU74b? (score: 1): Author: "jeff millar" <wa1hco@adelphia.net>; Date: Sun, 16 Nov 2003 11:16:29 -0500; Did you see... http://gref.cfn.ist.utl.pt/cupido/gu74amp.html http://nd2x.net/lz2us-3.html http://www.svetlana.com/docs/TechBulletins/technoteNo42.html These show about 1200W outs of a single tube in; /archives//html/Amps/2003-11/msg00216.html (9,731 bytes)
22. Re: [Amps] 3.5 kV 2A REGULATED Power Supply: Schematic ? (score: 1): Author: "jeff millar" <wa1hco@adelphia.net>; Date: Sun, 28 Dec 2003 17:46:19 -0500; There's really not much need for regulation on the plate supply on a PA. Look at the characteristic curves as shown at http://www.nd2x.net/gu84b.html Particularly the "Averaged Anode Characteristic C; /archives//html/Amps/2003-12/msg00435.html (11,466 bytes)
23. Re: [Amps] 3.5 kV 2A REGULATED Power Supply: Schematic ? (score: 1): Author: "jeff millar" <wa1hco@adelphia.net>; Date: Mon, 29 Dec 2003 23:35:02 -0500; Technically, the statement below is only partly true, and not enough to worry about in any case. Case 1: The extra signal added to the grid is something like hum or or voltage variation that's not re; /archives//html/Amps/2003-12/msg00465.html (12,646 bytes)
24. Re: [Amps] 3.5 kV 2A REGULATED Power Supply: Schematic ? (score: 1): Author: "jeff millar" <wa1hco@adelphia.net>; Date: Tue, 30 Dec 2003 18:20:18 -0500; Make sure to distinguish between grid bias supplies with truly regulated output (with feedback) and bias supplies with low output impedance. It's a lot simpler to make a stiff supply by resistively l; /archives//html/Amps/2003-12/msg00471.html (10,516 bytes)
25. Re: [Amps] Switch-mode HV power supply (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sun, 14 Mar 2004 08:43:43 -0500; Oleg... Can you provide a URL? Google could not find the site you mention. jeff, wa1hco Oleg Skydan wrote: Hi, All ! The reason for this inquiry is that I'm preparing a talk on power amps for the GM; /archives//html/Amps/2004-03/msg00148.html (8,826 bytes)
26. Re: [Amps] filament supply options (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sat, 24 Apr 2004 13:51:21 -0400; Things to think about - Cold resistance much lower than hot, PS may fold back on overcurrent and never light up the tube - Add some series resistance to limit surge current when cold...For example, a; /archives//html/Amps/2004-04/msg00176.html (9,571 bytes)
27. Re: [Amps] filament supply options (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sun, 25 Apr 2004 23:36:52 -0400; If Voltage across the filament caused bias/linearity/gain variation problems, then all amplifiers with AC on their filaments would have hum on the transmitted signal. 60 Hz on the filament varies ver; /archives//html/Amps/2004-04/msg00206.html (8,617 bytes)
28. Re: [Amps] cooling a high power rf mosfet amp?? (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Mon, 03 May 2004 08:30:30 -0400; The use of copper in heat sinks is primarily to spread the head from the transistors to the metal better, since you transistors run cool, the problem is more in the heat sink to air interface. Fans w; /archives//html/Amps/2004-05/msg00027.html (8,619 bytes)
29. [Amps] 8877 Input network testing (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Thu, 15 Jul 2004 21:54:14 -0400; I'm restoring an 8877 on 2M and it needs a better match on the input network. I've designed several input network options and now need to test them. Here's some questions that I hope someone can answ; /archives//html/Amps/2004-07/msg00090.html (7,334 bytes)
30. Re: [Amps] GS 35B (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sun, 25 Jul 2004 01:46:04 -0400; Note the phrase "grid driven". None of the nd2x.net QRO GS-35B, including DL4MEA, amps uses grid driven. It would be an interesting choice with less drive power required. But probably a lot more than; /archives//html/Amps/2004-07/msg00178.html (8,889 bytes)
31. Re: [Amps] Website for QRO stuff (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Tue, 07 Sep 2004 19:35:00 -0400; All I see after trying a variety of variations on the URL is a bunch of 404 Not Founds and a CB Amp repair shop. ...just what we need, a deep discussion of sweep tube linears. Do you have a more spec; /archives//html/Amps/2004-09/msg00165.html (7,487 bytes)
32. Re: [Amps] 2m Linear Amp Enquiry (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Mon, 13 Sep 2004 23:14:33 -0400; Pi Net's don't work on 2M, but here's a site that shows how to use HF techniques for building 2M PA's http://nd2x.net/yu1aw-2m-easy.html Note he uses the Russian triodes like Jerry suggests. jeff, wa; /archives//html/Amps/2004-09/msg00258.html (8,945 bytes)
33. Re: [Amps] Line Sections As Plate Lines (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Thu, 23 Sep 2004 13:08:51 -0400; The plate lines are not 1/4 or 1/2 wave long because the resonance and matching has to include the effects of the tuning capacitor and output coupling capacitor. This effect shows up well on a smith; /archives//html/Amps/2004-09/msg00428.html (8,644 bytes)
34. Re: [Amps] Line Sections As Plate Lines (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Thu, 23 Sep 2004 19:15:22 -0400; I had a chance to look at the web sites. The PA3CSG design consists of a "1/2" wave line load at both ends, tube output C at one end and the tune and coupling C at the other end. The low impedance mi; /archives//html/Amps/2004-09/msg00434.html (8,983 bytes)
35. Re: [Amps] Line Sections As Plate Lines (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Thu, 23 Sep 2004 19:19:01 -0400; Any coincidence between 1/4 wave in free space and the actual length of the 1/2 wave line is purely an accident of the numbers. The line is best modeled as an inductor to with caps at each end that r; /archives//html/Amps/2004-09/msg00435.html (9,319 bytes)
36. Re: [Amps] Line Sections As Plate Lines (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Fri, 24 Sep 2004 19:30:17 -0400; The line is not physically 1/2 wave long because it's loaded at both ends by capacitance. I use the RF Dude's smith chart program (or the Linux one by Lapo Pieri, IK5NAX) and enter some starting valu; /archives//html/Amps/2004-09/msg00447.html (11,343 bytes)
37. Re: [Amps] Design for plate stripline for 144 MHZ (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Fri, 24 Sep 2004 19:51:40 -0400; Manny... Check out the response I just sent to the reflector and Jim N9RF. Do you have a preferred design style from http://nd2x.net or some other source? The basic decisions include W6PO style with; /archives//html/Amps/2004-09/msg00448.html (9,242 bytes)
38. Re: [Amps] Power Supply loaded DC output (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sat, 02 Oct 2004 09:34:10 -0400; just saying a 10% drop with load doesn't address all the factors * Output capacitance * Transformer winding resistance * Line resistance The ARRL handbook has a graph that shows the voltage can drop; /archives//html/Amps/2004-10/msg00012.html (9,193 bytes)
39. Re: [Amps] Plate tank for 144 MHz using 8877 (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Sat, 09 Oct 2004 00:23:09 -0400; Bill Check out the "easy build" amplifiers from this site http://nd2x.net/yu1aw-2m-easy.html The design shows a GS-31B or GS-35B, but the same output network will work for an 8877. I've also been wor; /archives//html/Amps/2004-10/msg00109.html (9,048 bytes)
40. Re: [Amps] GI-46B Question (score: 1): Author: jeff millar <wa1hco@adelphia.net>; Date: Fri, 15 Oct 2004 08:57:55 -0400; Bob the advertisement says the GI-46b is a variant on the GI-7b. But its interesting to read the description of the GI-6B, particularly the transfer capacitance (http://nd2x.net/gi6b.html). Lets comp; /archives//html/Amps/2004-10/msg00215.html (8,009 bytes)

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