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101. Re: [Amps] Amps and ROHS (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sun, 21 May 2006 12:14:35 +0100; The "lead-free" regulations will only apply to new production that is placed on the market AFTER the cutoff date. That term "placed on the market" has a very specific legal meaning - roughly speaking; /archives//html/Amps/2006-05/msg00262.html (12,448 bytes)
102. Re: [Amps] Alpha 91b fan/blower motor (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Wed, 24 May 2006 07:25:49 +0100; Pressure can be tricky to measure at low levels. It is like trying to measure voltage with an insensitive meter, and no clear idea where you should apply the two probes. You can measure "something"..; /archives//html/Amps/2006-05/msg00312.html (11,381 bytes)
103. Re: [Amps] 813's (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sun, 28 May 2006 08:54:14 +0100; WARNING: Do not operate 6ft rack on its side. -- 73 from Ian GM3SEK _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/; /archives//html/Amps/2006-05/msg00440.html (8,864 bytes)
104. Re: [Amps] More LK500 (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Mon, 29 May 2006 11:18:39 +0100; It looks like your low B+ problem is because the step start relay is not pulling in. This means that the resistor is permanently in series with the mains... and will be having a very hard time. Don't; /archives//html/Amps/2006-05/msg00476.html (8,225 bytes)
105. Re: [Amps] teeny copper strap (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Wed, 7 Jun 2006 14:10:09 +0100; It's certainly thick enough to carry the RF current. Thanks to the skin effect, even very thin copper foil in a 5mm (3/16in) width will carry 1500W at HF without getting warm (that's 5.5A into 50 ohm; /archives//html/Amps/2006-06/msg00195.html (8,432 bytes)
106. Re: [Amps] teeny copper strap (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Wed, 7 Jun 2006 17:55:31 +0100; Most amps have enough space to mount two long resistors in a "V" configuration, so the two ends are a short distance apart while the mid-point is tucked away somewhere safe. The SB-220 has a separate; /archives//html/Amps/2006-06/msg00206.html (10,825 bytes)
107. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Wed, 12 Jul 2006 22:57:41 +0100; That is too simple a question, because the answer depends on the application as well as the frequency. In locations where the RF+DC voltage gradient or the RF current density are high, you need a bet; /archives//html/Amps/2006-07/msg00354.html (10,579 bytes)
108. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 13 Jul 2006 08:01:17 +0100; Sorry, I don't keep any magazines as old as that... so what does the photograph show? -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek __________________; /archives//html/Amps/2006-07/msg00360.html (9,050 bytes)
109. Re: [Amps] Mica cap substitute \ alternative (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 13 Jul 2006 12:21:41 +0100; The things that limit RF power handling are: * voltage breakdown * temperature rise within the dielectric material. Temperature rise is important because it may lead to other indirect effects, eg mel; /archives//html/Amps/2006-07/msg00363.html (9,766 bytes)
110. Re: [Amps] Switching Power Supplies (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sat, 15 Jul 2006 00:00:23 +0100; In Field Day use, with more than one station hooked up to the same generator, there can be violent swings in the line voltage as stations switch unpredictably between transmit and receive. A regulate; /archives//html/Amps/2006-07/msg00399.html (8,848 bytes)
111. Re: [Amps] Switching Power Supplies (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sat, 15 Jul 2006 11:22:43 +0100; Indirectly heated cathodes do have some thermal inertia which tends to keep the temperature more constant... but the scenarios I've experienced have involved sags in line voltage that were a lot more; /archives//html/Amps/2006-07/msg00415.html (10,929 bytes)
112. Re: [Amps] QRO membership revoked (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Mon, 17 Jul 2006 19:21:50 +0100; No problem - there isn't any way to enter "0.026", so it won't appear on your permanent record. -- 73 from Ian GM3SEK _______________________________________________ Amps mailing list Amps@contesting; /archives//html/Amps/2006-07/msg00541.html (8,184 bytes)
113. Re: [Amps] crowbar TSPA (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 20 Jul 2006 23:02:37 +0100; The opto-triggered crowbar by OE5JFL has been copied by several UHF amplifier builders with very valuable tubes to protect, and works well. Since that article was written, 1200V thyristors have becom; /archives//html/Amps/2006-07/msg00695.html (10,988 bytes)
114. Re: [Amps] Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 20 Jul 2006 23:07:28 +0100; But despite repeated requests, you have never provided a detailed explanation for this bending force, in terms of the familiar "left-hand law" that makes an electric motor work; or identified what is; /archives//html/Amps/2006-07/msg00696.html (10,731 bytes)
115. Re: [Amps] Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 20 Jul 2006 23:40:45 +0100; I don't know of any electronic protection circuit that actually works that way. Despite requests in the past, Rich has never shown an example of what he claims. Contrary to earlier assertions, many h; /archives//html/Amps/2006-07/msg00697.html (12,953 bytes)
116. Re: [Amps] AMPS (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Thu, 20 Jul 2006 23:50:16 +0100; Despite requests in the past, you have never provided a specific example of a circuit that needs a "grid protect transistor rated at >50A". The schematic of my grid-protection circuit is in the Triod; /archives//html/Amps/2006-07/msg00699.html (8,901 bytes)
117. Re: [Amps] Grid fuses (was: Life and gain of 3-500Z) (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Fri, 21 Jul 2006 08:44:23 +0100; We're discussing the same question twice over. I have responded in the other thread of the discussion, so please let's close off this one. -- 73 from Ian GM3SEK http://www.ifwtech.co.uk/g3sek _______; /archives//html/Amps/2006-07/msg00713.html (11,358 bytes)
118. Re: [Amps] AMPS (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Fri, 21 Jul 2006 08:44:09 +0100; Yesterday ended with two almost identical exchanges in different threads of the debate. I am pulling both back together here. I had replied: The question is about the control circuit, not the type of; /archives//html/Amps/2006-07/msg00714.html (11,332 bytes)
119. Re: [Amps] AMPS (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sat, 22 Jul 2006 09:29:22 +0100; Q1 is part of an 'electronic zener' circuit that provides cathode bias. In normal operation it carries cathode current, and also <normal> levels of grid current. The current paths for normal anode an; /archives//html/Amps/2006-07/msg00842.html (10,832 bytes)
120. Re: [Amps] AMPS (score: 1): Author: Ian White GM3SEK <gm3sek@ifwtech.co.uk>; Date: Sat, 22 Jul 2006 10:09:17 +0100; Sorry, my previous posting was an intermediate draft. What I meant to post was this version, so please ignore the previous one. There is nothing technically different below, but I tried to make the e; /archives//html/Amps/2006-07/msg00843.html (13,467 bytes)

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