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1. [Amps] Glitch resistors (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 4 Mar 2002 22:02:43 +0000
This question comes up regularly (and I remember foolishly volunteering to prepare a FAQ web page about it) so can we take this opportunity to pull together everything we've learned from one another?
/archives//html/Amps/2002-03/msg00054.html (10,442 bytes)

2. [Amps] Fans for 4cx1000/1500 question (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Tue, 5 Mar 2002 14:22:03 +0000
Agreed about the cardboard box mock-up, just to see if the blower is big enough. Broadening the answer, it is better to measure the cfm directly by letting the exhaust air blow up a thin plastic bag,
/archives//html/Amps/2002-03/msg00097.html (10,614 bytes)

3. [Amps] Fans for 4cx1000/1500 question (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Tue, 5 Mar 2002 22:49:38 +0000
These pressure figures only relate to the one particular method of blowing: upward through the socket, chimney and anode cooler in series. For other methods of blowing, the pressure drops will be dif
/archives//html/Amps/2002-03/msg00104.html (9,559 bytes)

4. [Amps] Fans for 4cx1000/1500 question (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Tue, 5 Mar 2002 22:43:20 +0000
Just as practical as it is on VHF and above, where it is the standard method. The only reason it isn't used so much on HF is because many people feel it's OK to let RF wander all around the insides o
/archives//html/Amps/2002-03/msg00105.html (9,492 bytes)

5. [Amps] Glitch resistors (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Fri, 8 Mar 2002 18:38:49 +0000
Do you mean: "Not needed with LC filter, only C filter. Right?" If so, the answer's No - wrong. They both have a C on the output, and there is more than enough energy stored in a typical C to damage
/archives//html/Amps/2002-03/msg00188.html (10,078 bytes)

6. [Amps] Triode and Tetrode Boards kits - UK and Europe only (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Wed, 13 Mar 2002 17:05:03 +0000
This is for the UK and Europe only (apologies to all others for the bandwidth). Normally I do not sell kits of components for my Triode Board and Tetrode Boards, because you can buy them from supplie
/archives//html/Amps/2002-03/msg00278.html (7,819 bytes)

7. [Amps] 10 Meters (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Thu, 14 Mar 2002 09:08:02 +0000
I remember having great difficulty getting a weak Spanish station to understand the phonetic "Sierra" in my callsign (in spite of it being a Spanish word) but the longer "Santiago" worked immediately
/archives//html/Amps/2002-03/msg00287.html (9,617 bytes)

8. [Amps] config cathode-drive Amp with a Tetrode? (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Fri, 15 Mar 2002 17:19:13 +0000
Option 1 will work with some tubes, but it is not what the original tube designer intended (g1 and g2 of a tetrode are supposed to be at different potentials). Some tubes will handle this type of ope
/archives//html/Amps/2002-03/msg00351.html (8,558 bytes)

9. [Amps] MOV's (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sat, 16 Mar 2002 00:59:29 +0000
That's certainly true in this case, where the switching surge and the energy to be absorbed are completely predictable. To choose the right MOV for this kind of protection you only need the good engi
/archives//html/Amps/2002-03/msg00364.html (8,479 bytes)

10. [AMPS] Alpha 76 and 78 tube conversions (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sat, 2 Feb 2002 15:13:43 +0000
Part of the problem with using a GI7 as a 3CX400 substitute in an existing amp is the massive sand-cast anode cooler, which takes up a lot of space and is really not very efficient - it only works be
/archives//html/Amps/2002-02/msg00023.html (11,672 bytes)

11. [AMPS] gs35 internals (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 18 Feb 2002 07:28:38 +0000
Yup, they're there. Love that tea-strainer grid - real agricultural engineering! In more detail, please can you confirm which (if any) of the arcs has either (a) holed the grid, (b) marked the cathod
/archives//html/Amps/2002-02/msg00179.html (7,854 bytes)

12. [AMPS] gs35 internals (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 18 Feb 2002 11:30:57 +0000
Thanks, Steve... very interesting. It confirms that arcs from anode to grid do affect the cathode underneath as well. Any idea how the tube went dud? Did it ever work, or might it have been soft on a
/archives//html/Amps/2002-02/msg00184.html (7,962 bytes)

13. [AMPS] mof resistors (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sat, 23 Feb 2002 23:52:22 +0000
In Europe, small resistors are available in both carbon film (cheaper, higher tolerance) and metal film (a little more expensive but also closer tolerance). Medium power (1-3W) are almost exclusively
/archives//html/Amps/2002-02/msg00252.html (10,885 bytes)

14. [AMPS] test (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sat, 12 Jan 2002 08:47:43 +0000
Maybe we all made a New Year's resolution to take the nice pink tablets every day? Don't worry - it won't last. -- 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (
/archives//html/Amps/2002-01/msg00086.html (7,363 bytes)

15. [AMPS] amplifier help (score: 1)
Author: Ian White <g3sek@ifwtech.com> (Ian White)
Date: Wed, 16 Jan 2002 13:23:43 +0000
Forwarded from Steve, G8GSQ: When I worked making rf power transistors, 'pill' was used to describe the piece of BeO when it wasn't attached to the mounting flange. Skipp's comments were pretty compr
/archives//html/Amps/2002-01/msg00111.html (8,096 bytes)

16. [AMPS] pills and rc feedback (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Tue, 22 Jan 2002 08:23:45 +0000
...in a subtle move to give anti-spam services a bad name? Well, it almost fits the facts. My ISP was another victim of this useless "service". SpamCop blocks mail from any ISP server that has been u
/archives//html/Amps/2002-01/msg00160.html (8,875 bytes)

17. [AMPS] Shunt regulated high voltage psu (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sun, 27 Jan 2002 09:43:47 +0000
There are several downloadable articles at: http://www.ifwtech.com/g3sek/boards/tetrode/tetrode-3.htm MOSFETs are better than bipolars for this application, because they don't suffer from second brea
/archives//html/Amps/2002-01/msg00195.html (9,278 bytes)

18. [AMPS] Shunt regulated high voltage psu (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Sun, 27 Jan 2002 18:58:31 +0000
Failures, you can never discount! It's very bad design to operate semiconductors from rail voltages that are above their breakdown voltage - even if they're never "supposed" to see that full voltage.
/archives//html/Amps/2002-01/msg00207.html (9,515 bytes)

19. [AMPS] Shunt regulated high voltage psu (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 28 Jan 2002 09:49:54 +0000
It doesn't make sense to spend money on a high-power, high-voltage zener (don't forget the heatsink) when you can uprate the shunt MOSFET for much less cost. The only exception would be if you insist
/archives//html/Amps/2002-01/msg00216.html (10,811 bytes)

20. [AMPS] Shunt regulated high voltage psu (score: 1)
Author: Ian White, G3SEK" <g3sek@ifwtech.com (Ian White, G3SEK)
Date: Mon, 28 Jan 2002 14:31:06 +0000
We're trying to solve two different problems here. One is transients, and all the methods Tom proposes are workable. For this particular application my own preference is Varistors, but it's no big de
/archives//html/Amps/2002-01/msg00229.html (11,495 bytes)


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