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121. [AMPS] Silver Plating question (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 22 Sep 1999 18:46:43 +0100; [That's what was in the back of my mind... ] I distinctly remember Mr Fowler himself posting messages on one of the newsgroups or lists, but couldn't find any of them on DejaNews by searching on "sil; /archives//html/Amps/1999-09/msg00222.html (13,243 bytes)
122. [AMPS] Re: (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Mon, 2 Aug 1999 07:49:01 +0100; Most peak-reading circuits do attempt to create this dual time constant. The two problems are the charging rate of the capacitors, and excessively long discharge times. First, the modulation peak tha; /archives//html/Amps/1999-08/msg00022.html (9,591 bytes)
123. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 4 Aug 1999 23:23:16 +0100; Even then, they may not be close enough to distinguish between tank "resonances". The test of accuracy of the design formula is to analyse the resulting network with the load present, and back-calcul; /archives//html/Amps/1999-08/msg00096.html (9,835 bytes)
124. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 5 Aug 1999 09:49:19 +0100; Evidently - like to tell us your definition? The definition I'm using is Q = XL/Rs, where Rs is the transformed effect of all resistive components, when made to appear in a series loop with L. [ For; /archives//html/Amps/1999-08/msg00103.html (11,778 bytes)
125. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 5 Aug 1999 23:12:46 +0100; I can't believe I'm reading this. If you truly believe that the definition of a quantity like Q is something that can change according to whose pi-network formulae you use, then - I'm sorry, but it h; /archives//html/Amps/1999-08/msg00120.html (9,877 bytes)
126. [AMPS] Front Panel Labeling ??? (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 7 Aug 1999 08:43:59 +0100; Any precision drawing package will be OK, especially if it has facilities for laying out lines at specified angles to each other. I've regularly used AutoSketch for re-scaling meters, including multi; /archives//html/Amps/1999-08/msg00147.html (9,097 bytes)
127. [AMPS] Front Panel Labeling ??? (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sun, 8 Aug 1999 09:39:32 +0100; Thanks, Terry! 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.demon.co.uk/g3sek -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Sub; /archives//html/Amps/1999-08/msg00158.html (8,526 bytes)
128. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 11 Aug 1999 08:39:47 +0100; Hard to guess remotely, but here are a few thoughts... When there are no terminating resistors, it's easy to calculate the resonant frequency. But when there is one or more terminating resistor, you; /archives//html/Amps/1999-08/msg00197.html (10,480 bytes)
129. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 12 Aug 1999 17:43:33 +0100; Bob, you may be referring to the "old" ARRL method, which has all the faults you describe. This was superseded by a much more exact method, which after some years appeared in the 1995 Handbook and al; /archives//html/Amps/1999-08/msg00245.html (9,646 bytes)
130. [AMPS] Pi-Net math (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Fri, 13 Aug 1999 18:12:38 +0100; Unfortunately not... Your method gives the correct resonance when both input and output are unloaded, but when the output is loaded with 50 ohms, the resonance moves down to about 6.68MHz. I think we; /archives//html/Amps/1999-08/msg00250.html (11,140 bytes)
131. [AMPS] RE: 4cx10000 (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 10 Jul 1999 13:21:07 +0100; I accept that heavier loading leads to better linearity, but please can you explain why this is true? 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://; /archives//html/Amps/1999-07/msg00183.html (8,581 bytes)
132. [AMPS] Bias question (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Mon, 12 Jul 1999 18:35:36 +0100; Tom is right- bipolar power transistors do need a constant-voltage base bias supply (leaving aside the point about temperature compensation). When RF drive is applied, it creates both AC and DC curre; /archives//html/Amps/1999-07/msg00221.html (8,778 bytes)
133. [AMPS] The DAF Amp (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Tue, 13 Jul 1999 23:06:42 +0100; If it's cathode-driven, it isn't a G2DAF - it's somebody else's even weirder creation. I can see why someone might want to try the G2DAF idea to modify a typical cathode-driven "triode-connected tetr; /archives//html/Amps/1999-07/msg00270.html (10,096 bytes)
134. [AMPS] The DAF Amp (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 14 Jul 1999 18:15:35 +0100; I don't know anything at all about the offshoots. The original circuit was <apply visual imagination here>: * 300 ohm grid resistor * 0.005uF coupling cap to the junction between two 6U4GT's connecte; /archives//html/Amps/1999-07/msg00290.html (9,583 bytes)
135. [AMPS] G2DAF (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 15 Jul 1999 06:57:06 +0100; 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.demon.co.uk/g3sek -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@c; /archives//html/Amps/1999-07/msg00293.html (8,328 bytes)
136. [AMPS] Impedance of amplifiers (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 17 Jul 1999 23:39:52 +0100; If we're talking about the same formulae, they were approximations that assumed a high loaded Q. They were probably good enough for designing output tank circuits, but gave major errors in Q values f; /archives//html/Amps/1999-07/msg00340.html (10,326 bytes)
137. [AMPS] DAF Amp & others of similiar ilk. (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 22 Jul 1999 22:44:11 +0100; It's a derivative, because it generates the screen voltage by rectifying the RF drive, but: * The screen rectifier arrangement is different * It uses sweep tubes * It uses cathode bias ...a bit like,; /archives//html/Amps/1999-07/msg00414.html (8,022 bytes)
138. [AMPS] Re: (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Tue, 27 Jul 1999 08:18:51 +0100; Not against a 'scope, but ultimately against a terminating thermal wattmeter which is the only system that is absolute and verifiably broadband. Scopes and all kinds of "through-line" wattmeters don'; /archives//html/Amps/1999-07/msg00514.html (11,395 bytes)
139. [AMPS] Re: (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Tue, 27 Jul 1999 20:12:34 +0100; One doesn't. As I said, one calibrates the power measuring device on CW, and then one tackles the *separate* question of grabbing the true peak of the modulation. It isn't so much a question of which; /archives//html/Amps/1999-07/msg00542.html (13,011 bytes)
140. [AMPS] Tube question (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Fri, 30 Jul 1999 12:12:36 +0100; Microwave oven fuses are now readily available at very reasonable cost, rated for HV and at currents up to 1A. (I know, I know, 1A is no good for tubes with handles...) 73 from Ian G3SEK Editor, 'The; /archives//html/Amps/1999-07/msg00639.html (7,799 bytes)

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