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361. [AMPS] Re: Grounding question (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sun, 24 Aug 1997 10:57:28 +0100; See my web pages for design details of a good active bias circuit. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) www.ifwtech.demon.co.uk/g3sek -- FAQ on WW; /archives//html/Amps/1997-08/msg00176.html (7,099 bytes)
362. [AMPS] parasitics in VHF amplifiers (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 27 Aug 1997 13:25:21 +0100; I'd agree with the suggestion to use a pi-output. With link coupling and a series-tuning C, the loading tends to peak in the middle of the capacitor's range, so it's always rather uncertain whether y; /archives//html/Amps/1997-08/msg00208.html (8,640 bytes)
363. [AMPS] Grid capacitors (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Fri, 11 Jul 1997 12:52:15 +0100; Removal of gas can occur by several physical and chemical 'scavenging' processes that may take place on timescales of seconds to hours. A sudden, small release of gas could cause an arc because the s; /archives//html/Amps/1997-07/msg00050.html (9,758 bytes)
364. [AMPS] Grid capacitors (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 12 Jul 1997 13:28:37 +0100; Rich Measures asked: The scavenging process is a chemical reaction. It doesn't need electric power. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) www.ifwte; /archives//html/Amps/1997-07/msg00058.html (8,961 bytes)
365. [AMPS] Grid capacitors (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 12 Jul 1997 21:05:36 +0100; Fair point! Thank you. Back to the original question, then: exactly what produced the mechanical force that made the filaments move? (BTW, Rich, this "Rauchian" word of yours is getting bloody irrita; /archives//html/Amps/1997-07/msg00064.html (9,940 bytes)
366. [AMPS] Grid capacitors (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sun, 13 Jul 1997 09:28:42 +0100; I'm still using the neutral term "during the event". Now can you take it down to the next level of detail, please: what currents flow in which wires, in which directions, and how do they produce the; /archives//html/Amps/1997-07/msg00066.html (10,206 bytes)
367. [AMPS] Re: Bent filaments (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Mon, 14 Jul 1997 07:39:55 +0100; That certainly has to be true - aided by bad design that fails to limit the maximum surge current, fails to protect the meters with diodes (BIG diodes) and then forgets to turn off the mains supply t; /archives//html/Amps/1997-07/msg00090.html (10,190 bytes)
368. [AMPS] Grid capacitors (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Mon, 14 Jul 1997 13:42:55 +0100; To further things come to mind. One was the message from Reid Brandon at Eimac, posted a few weeks ago by W0UN. Here's the currently relevant part: Someone else recalled in an e-mail (posted by permi; /archives//html/Amps/1997-07/msg00093.html (11,815 bytes)
369. [AMPS] Hello from a new member (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 16 Jul 1997 07:39:48 +0100; That sounds like a logical interlock sequence. The worst-case event for the HV supply is an internal or external arc which almost short-circuits the anode to chassis. Follow Eimac's advice and use a; /archives//html/Amps/1997-07/msg00107.html (10,293 bytes)
370. [AMPS] screen voltage supply (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Fri, 18 Jul 1997 12:50:55 +0100; Yes, it's a common technique - it can be very power-hungry (work out the wattage of the dropper resistor) but it does have the advantage that screen voltage is automatically removed if the B+ fails.; /archives//html/Amps/1997-07/msg00136.html (8,456 bytes)
371. [AMPS] re:4-250A (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 19 Jul 1997 18:56:18 +0100; Rich Measures wrote in reply to G3RZP, who is away from his e-mail for most/all of next week: These curves apply whether grid current flows or not. The x axis is Vg(max)/Vbias, and across most of the; /archives//html/Amps/1997-07/msg00148.html (9,398 bytes)
372. [AMPS] re:4-250A (AB2 in grid-driven amplifiers) (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Tue, 22 Jul 1997 20:54:31 +0100; On the contrary, Mike, thank you for posting this. [snip] Thank you Mike - that's exactly the point! Power amplifier design and performance is far too complex a subject for absolute statements using; /archives//html/Amps/1997-07/msg00165.html (9,763 bytes)
373. [AMPS] Re: 2m legal limit amps (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White); Date: Tue, 22 Jul 1997 23:02:22 +0100; Hello Carl I'm not trying to evade your question, Carl. Give me time to talk this though with GW4FRX and I *will* come back to you and the group this time. (It may take a few days, depending on what; /archives//html/Amps/1997-07/msg00167.html (9,639 bytes)
374. [AMPS] Re: 2m legal limit amps (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White); Date: Wed, 23 Jul 1997 07:32:38 +0100; Barry, K8SD asked: Yes, a ZL has tried it and it does work, though the benefits are not as great as for 2C39s. I think that's basically because the 2C39 cross-flow air cooler is rather ineffective, l; /archives//html/Amps/1997-07/msg00177.html (9,000 bytes)
375. [AMPS] Water cooled external anodes (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Wed, 23 Jul 1997 17:11:01 +0100; That's pretty much the idea. The N6CA article seems to have tied down all the problems in the water circuit. Great for CW, maybe, but it doesn't add a single watt to the available *linear* output - w; /archives//html/Amps/1997-07/msg00185.html (7,772 bytes)
376. [AMPS] Re: 2m legal limit amps (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White); Date: Fri, 25 Jul 1997 18:26:59 +0100; It looks like GW4FRX can make some more measurements of IMD to answer your question more specifically, Carl. What he proposes to do is: 1. Set up 2*4CX250R with Va 1500V, Vg2 350V and adjust Vg2 to; /archives//html/Amps/1997-07/msg00216.html (14,203 bytes)
377. [AMPS] Re: 2m legal limit amps (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White); Date: Sat, 26 Jul 1997 00:29:18 +0100; Carl (>) wrote in reply to me (>>): Whoops, sorry, t6ping error on my part - I meant to type "adjust Vg1". Vg2 will be set to EIMAC's datasheet value and left there. A great deal of the rest of your; /archives//html/Amps/1997-07/msg00226.html (14,818 bytes)
378. [AMPS] Tetrode Amp articles needed (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Thu, 5 Jun 1997 07:24:43 +0100; Very true - but how much of this is due to the tube characteristics, and how much to the power supply? Many power supplies designed for AB1 have very high output impedances (several K or more), so th; /archives//html/Amps/1997-06/msg00014.html (9,845 bytes)
379. [AMPS] Tetrode Amp articles needed (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Fri, 6 Jun 1997 17:27:42 +0100; With the correct drive levels and power supplies, 4CX250, 4CX350 and probably 4CX400 amplifiers can give excellent-quality signals. A lot of work was done on this in Europe 10-15 years ago. At that t; /archives//html/Amps/1997-06/msg00059.html (10,986 bytes)
380. [AMPS] PA Recommendation Wanted (score: 1): Author: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK); Date: Sat, 7 Jun 1997 08:13:09 +0100; "Match" in the sense of "adjust to be compatible" - oops, sorry, wrong newsgroup! Carl is right on two points. It's the operators and the power supplies that are to blame, not the tubes themselves. T; /archives//html/Amps/1997-06/msg00088.html (10,232 bytes)

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