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Total 257 documents matching your query.

1. Re: [Amps] Trimming the transmission line (score: 1)
Author: "Saandy Eban" <>
Date: Fri, 12 Oct 2007 18:29:11 +0200
/archives//html/Amps/2007-10/msg00160.html (9,051 bytes)

2. Re: [Amps] PEP Wattmeters (score: 1)
Author: "Saandy Eban" <>
Date: Fri, 19 Oct 2007 08:39:24 +0200
NOOO, IT'S NOT!!!! At least Heathkit had on the market a dual function wattmeter (published also in QST)and MFJ has also at least one model- not a tuner with SWR/Wattmeter included- but a stand alone
/archives//html/Amps/2007-10/msg00224.html (9,487 bytes)

3. Re: [Amps] 8877 Filament choke (score: 1)
Author: "Saandy Eban" <>
Date: Fri, 16 Nov 2007 08:44:55 +0200
...for the most part, these amplifiers operate the 8877 in grounded grid configuration. As such, the input circuit is supposed to be above ground RFwise. Now, the capacitance between the cathode and
/archives//html/Amps/2007-11/msg00219.html (13,154 bytes)

4. Re: [Amps] Vacuum Variable Fatigue Failures (score: 1)
Author: "Saandy Eban" <>
Date: Sun, 17 Feb 2008 08:07:38 +0200
.all I can tell you is that, in 40 years in the profession, I never saw one with cracked bellows The only fault I ever saw was drying up of the tuning screw, with an attendant screech of the worst ki
/archives//html/Amps/2008-02/msg00110.html (9,034 bytes)

5. Re: [Amps] Transceiver Output Impedance (score: 1)
Author: "Saandy Eban" <>
Date: Sun, 9 Mar 2008 11:01:03 +0200
.....this is definitely not so! The load impedance of the final transistors is defined by Ohm's law so that for a defined high power the load they expect to see can be a few ohms only. Here is where
/archives//html/Amps/2008-03/msg00088.html (9,191 bytes)

6. Re: [Amps] Relays (score: 1)
Author: "Alex" <>
Date: Wed, 2 Apr 2008 09:41:04 +0300
Hi guys: It so happens that during the last 2 years or so I worked on high power amplifiers in the kilowatt range . PIN diodes are made by very few manufacturers, coming and going all the time. They
/archives//html/Amps/2008-04/msg00028.html (9,470 bytes)

7. Re: [Amps] Relays (score: 1)
Author: "Alex" <>
Date: Wed, 2 Apr 2008 12:59:30 +0300
OH, YEAH! Back in the sixties the radio Bible carried for years a T/R switch based on a triode. It was based on the principle of grid leak bias i.e. the RF developed bias for the tube to cut it of an
/archives//html/Amps/2008-04/msg00030.html (9,229 bytes)

8. Re: [Amps] Relays (score: 1)
Author: "Alex" <>
Date: Wed, 2 Apr 2008 22:19:57 +0300
.... I'll explain that noise point: In order to reduce the intrinsic resistance of the PIN diode, you have - especially with the BIG high power ones- to pass about 200mA or more through the receive d
/archives//html/Amps/2008-04/msg00045.html (14,471 bytes)

9. Re: [Amps] Relays (score: 1)
Author: "Alex" <>
Date: Wed, 2 Apr 2008 22:30:32 +0300
They DO have a reliability problem. Don't forget that the OFF diode has to be back biased by at least 3 times the RF voltage at the relevant power level: that means approximately 800V at the 1kW leve
/archives//html/Amps/2008-04/msg00047.html (10,410 bytes)

10. Re: [Amps] Fabrication & part placement (score: 1)
Author: "Alex" <>
Date: Fri, 18 Apr 2008 19:37:40 +0300
...well done! I would like only to add a small warning: there are tubes, like the 4-1000, which don't like to operate horizontally! They even stress it quite energetically on the data sheet. Soooo, i
/archives//html/Amps/2008-04/msg00241.html (9,209 bytes)

11. Re: [Amps] current in primary of microwave oven transformer (score: 1)
Author: "Alex" <>
Date: Wed, 23 Apr 2008 17:19:39 +0300
...guys this is normal behavior for all transformers! It is the result of the existence of a magnetizing inductance, usually depicted as a parallel inductance across the primary and every transformer
/archives//html/Amps/2008-04/msg00269.html (10,327 bytes)

12. Re: [Amps] current in primary of microwave oven transformer (score: 1)
Author: "Alex" <>
Date: Thu, 24 Apr 2008 13:11:17 +0300
...that's right and that's what cosine is about. With real high power animals its not unusual to see reactance canceling capacitors across the primary theyre sometimes automatically adjusted too! Ale
/archives//html/Amps/2008-04/msg00289.html (12,687 bytes)

13. Re: [Amps] HV transformer issue (score: 1)
Author: "Alex" <>
Date: Sun, 4 May 2008 10:02:30 +0300
Hi guys: This is definitely an eddy currents issue. Don't forget this is a potentially a 6kVA transformer: it doesn't take much of losses to generate enough current for that kind of heating. Many man
/archives//html/Amps/2008-05/msg00025.html (18,005 bytes)

14. Re: [Amps] Painting xfmrs (score: 1)
Author: "Alex" <>
Date: Mon, 5 May 2008 23:14:10 +0300
Hi Jeff: Actually it won't matter. Just use some heat conducting paint, like what was called Barbeque Paint. It's true that there were all kinds of stories about its high lead content but, as long as
/archives//html/Amps/2008-05/msg00051.html (8,653 bytes)

15. Re: [Amps] Painting xfmrs (score: 1)
Author: "Alex" <>
Date: Mon, 5 May 2008 23:59:18 +0300 it was for thermal reasons: being close to the tubes meant a lot of radiated heat and the white paint was for reflecting the radiated heat away from the transformer. Alex 4Z5KS Hi Jeff, I belie
/archives//html/Amps/2008-05/msg00056.html (10,044 bytes)

16. Re: [Amps] transformer in series......... (score: 1)
Author: "Alex" <>
Date: Tue, 13 May 2008 07:45:00 +0300
Noooooo! The variable transformers are connected in autotransformer configuration and there is NO isolation between the primary and the secondary. This is first of all a safety issue and a major one!
/archives//html/Amps/2008-05/msg00092.html (8,593 bytes)

17. Re: [Amps] Filter caps Ameritron 203 0578 (score: 1)
Author: "Alex" <>
Date: Mon, 19 May 2008 17:23:55 +0300
... a little suggestion, if the esthetic point of view is secondary: get a pair of 200Vdc capacitors of the kind used in computer power supplies. You can find them up to 1000uF, possibly more. Wire 2
/archives//html/Amps/2008-05/msg00124.html (9,226 bytes)

18. Re: [Amps] How to safely clean an amplifier? (score: 1)
Author: "Alex" <>
Date: Sat, 31 May 2008 22:56:40 +0300
You can get the reader at: it's a highly compressive file technique , used by BAMA and the Russian sites quite a lot. Alex 4Z5KS --Original Message-- From: [
/archives//html/Amps/2008-05/msg00222.html (9,891 bytes)

19. Re: [Amps] Import twist lock can electrolytics (score: 1)
Author: "Alex" <>
Date: Tue, 17 Jun 2008 07:22:07 +0300 ....I'll try to find the other addresses that I have and send them to you. 73 and all the best: Alex 4Z5KS /06/2008 07:20 ____________________________________
/archives//html/Amps/2008-06/msg00121.html (6,766 bytes)

20. Re: [Amps] {SPAM} Kilovac H-18 (score: 1)
Author: "Alex" <>
Date: Sun, 22 Jun 2008 07:44:56 +0300
...from my experience with Kilovac relays: 1) They tend to be on the high side as far as current consumption goes: 200mA for a 12V DPDT isn't unusual. An SPDT 26.5V coil reads about 635 Ohms and this
/archives//html/Amps/2008-06/msg00165.html (11,049 bytes)

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