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141. [AMPS] Another Stupid Question (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Mon, 3 Dec 2001 09:11:25 +0000; Shouldn't that read: "the effect is to raise the load impedance presented to the tube"? As I'd understood it, the function of the pi-network is not to match the notional plate impedance of the tube,; /archives//html/Amps/2001-12/msg00015.html (9,527 bytes)
142. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 08:22:14 +0000; This is only relevant when the two capacitors are very *different*. You then get a parallel resonance, between the lower capacitance and the self-inductance of the higher-value one. For example, if y; /archives//html/Amps/2001-12/msg00091.html (9,427 bytes)
143. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 12:41:02 +0000; We're still waiting for a specific reference to the circuit that has this design flaw. -- 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.; /archives//html/Amps/2001-12/msg00096.html (9,131 bytes)
144. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 12:59:50 +0000; [...] Certainly it's real. When you connect the two capacitors together at each end, you make a series-resonant loop. Guessing at values, two 1000pF caps, in series with a total of 8nH lead inductanc; /archives//html/Amps/2001-12/msg00100.html (10,248 bytes)
145. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 13:27:13 +0000; I know of no grid current monitoring circuits that behave as you describe - that's my point. This ball has been in your court for some months, Rich. If there are "several" such circuits, you'll have; /archives//html/Amps/2001-12/msg00110.html (9,238 bytes)
146. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 16:05:01 +0000; I had written: Not unless the current capacity is more than two times greater than each of the two paralleled caps. Since I don't know exactly what you mean, I wouldn't care to comment. Not at all -; /archives//html/Amps/2001-12/msg00119.html (11,181 bytes)
147. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 22:34:24 +0000; That's not very specific... and what exactly do you mean by an "interrupt transistor"? So you do have difficulty in naming even one specific circuit, then? -- 73 from Ian G3SEK Editor, 'The VHF/UHF D; /archives//html/Amps/2001-12/msg00125.html (10,107 bytes)
148. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Wed, 5 Dec 2001 22:54:09 +0000; They do not develop a new parallel resonance due to being connected together. And later: Certainly - these are all *series* resonances with their self-inductance (plus the inductance of the wire you; /archives//html/Amps/2001-12/msg00138.html (10,210 bytes)
149. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Thu, 6 Dec 2001 12:47:50 +0000; Thanks for providing some concrete information, Paul. So the way it's normally meant to operate is that grid current flows down through R3, and when the voltage drop exceeds about 0.6V it turns on Q2; /archives//html/Amps/2001-12/msg00141.html (12,154 bytes)
150. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Thu, 6 Dec 2001 13:18:07 +0000; [...] Sorry - "R3" should be R20, everywhere. -- 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: http://www.conte; /archives//html/Amps/2001-12/msg00142.html (9,754 bytes)
151. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Thu, 6 Dec 2001 16:42:34 +0000; If anyone other than Rich feels that I have not explained clearly enough in pervious postings why this is *not* a parallel resonance, I will try again. -- 73 from Ian G3SEK Editor, 'The VHF/UHF DX Bo; /archives//html/Amps/2001-12/msg00150.html (9,264 bytes)
152. [AMPS] Re: 6m amp blocking caps (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Fri, 7 Dec 2001 07:28:06 +0000; I already did: connect a 50 ohm resistor in parallel, and sweep the SWR analyzer for the lowest SWR. Details are in the MFJ analyzer manuals, which are downloadable. -- 73 from Ian G3SEK Editor, 'The; /archives//html/Amps/2001-12/msg00165.html (8,656 bytes)
153. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Fri, 7 Dec 2001 11:06:06 +0000; Paul Christensen wrote (regarding the Alpha PA-77): After downloading the PA-77 manual and schematic (from the excellent "Boat Anchor Manuals" site, http://bama.sbc.edu) it seems that the circuit is; /archives//html/Amps/2001-12/msg00166.html (11,068 bytes)
154. [AMPS] AL1500 (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Fri, 7 Dec 2001 12:03:28 +0000; The break time of a fuse depends crucially on the size of the overload. Remember that a fuse operates in a very simple way, by heating up a piece of very thin wire until it melts. For the fastest bre; /archives//html/Amps/2001-12/msg00167.html (11,678 bytes)
155. [AMPS] Transformer Current ratings (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Sat, 15 Dec 2001 15:00:07 +0000; Only indirectly. Weight is a rough indication of core cross-section, which is important but still only one factor in the transformer's overall performance. The rule of thumb was "Size of a six-pack =; /archives//html/Amps/2001-12/msg00234.html (12,015 bytes)
156. [AMPS] Transformer Current ratings (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Sat, 15 Dec 2001 18:09:44 +0000; Me too! -- 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.com/g3sek -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@c; /archives//html/Amps/2001-12/msg00239.html (9,067 bytes)
157. [AMPS] Transformer Current ratings (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Mon, 17 Dec 2001 13:28:07 +0000; The *effective* secondary resistance - including the contribution from the primary - is the value that should be used in calculations. If the primary resistance is too low to measure accurately (whic; /archives//html/Amps/2001-12/msg00295.html (9,607 bytes)
158. [AMPS] Inductors (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Tue, 18 Dec 2001 08:25:29 +0000; It works fine in 50MHz amplifiers, with no noticeable heating in the shorted turn if it is made from continuous copper (eg a slice from a seamless tube, or a disk with a hole punched out). The shorte; /archives//html/Amps/2001-12/msg00321.html (8,782 bytes)
159. FW: [AMPS] Bypassing Screen of 4cx800a for 50 MHz (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Thu, 20 Dec 2001 19:37:42 +0000; That's how you find out that the Varistor wasn't substantial enough. The choice between a Varistor and a spark-gap protector isn't always so clear-cut. The Varistor can start to conduct and provide p; /archives//html/Amps/2001-12/msg00400.html (11,757 bytes)
160. [AMPS] another myth on EMF (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK); Date: Mon, 5 Nov 2001 21:16:37 +0000; The methodology is to stick a pin in the map and draw a circle round it. Then you count the number of cancers inside that circle and compare with the national average. If you draw a circle big enough; /archives//html/Amps/2001-11/msg00059.html (10,547 bytes)

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