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Total 523 documents matching your query.

21. Re: [Amps] Ameritron AL-811H-- Again (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 1 Oct 2005 07:15:04 +0100
At the end of the day, the 572B isn't that good a tube for HF. OK, it 'gets by', but its structure isn't that good. As far as I can determine, it first appeared in the early 1950's as a zero bias aud
/archives//html/Amps/2005-10/msg00001.html (7,710 bytes)

22. Re: [Amps] Outgassing tubes. (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 5 Oct 2005 16:15:59 +0200 (CEST)
arc when they happen, but are often small enough to be removed by the chemical gettering action (which is built into most transmitting tubes even if you don't know it).> The tantalum anode (as used i
/archives//html/Amps/2005-10/msg00130.html (7,313 bytes)

23. Re: [Amps] Racal Dana 9028P (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 1 Nov 2005 02:46:20 +0100 (CET)
One of that series ( and I can't remember which) was fully synthesised and very quiet. Plus very heavy and not too small. 73 Peter W6/G3RZP _______________________________________________ Amps mailin
/archives//html/Amps/2005-10/msg00734.html (7,120 bytes)

24. Re: [Amps] Mobile high power (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 1 Nov 2005 03:08:04 +0100 (CET)
How do you keep within the ICNIRP limits with high power? They suggest a maximum field strength at HF where a piece of ungrounded metal could be touched of 30volts/metre maximum. 60 volts/meter maxim
/archives//html/Amps/2005-10/msg00735.html (8,738 bytes)

25. Re: [Amps] Aluminum alloys for panels? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 16 Nov 2005 10:37:47 +0100 (CET)
With unknown or hard alloys, you can have trouble with the stuff cracking if you want to bend it. Heat treatment is a specialist job, but for rough and ready work at home, I find that smearing the ba
/archives//html/Amps/2005-11/msg00227.html (8,069 bytes)

26. Re: [Amps] Question about RCD aka GFI (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 16 Nov 2005 11:00:00 +0100 (CET)
OK, not quite on the 4 wire safety topic. Do any of the European readers know a source of RF proof RCD (Residual Current Device - European name for a GFI)? I have found (the hard way) the products of
/archives//html/Amps/2005-11/msg00228.html (7,309 bytes)

27. Re: [Amps] 220V wiring: Was Question about safety ground connection (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 17 Nov 2005 09:45:34 +0100 (CET)
standards are often doing so on a voluntary basis.< I've been professionally involved with standards production in both the US and Europe over about the last 15 years, and would only say Jim is parti
/archives//html/Amps/2005-11/msg00262.html (9,585 bytes)

28. Re: [Amps] 220V wiring: Was Question about safety ground connection (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 17 Nov 2005 10:08:43 +0100 (CET)
can not become a shock hazard if the safety-ground wire is severed by an anomaly.< But an open neutral in such a case leaves the enclosure at some undetermined voltage above ground. Depending on how
/archives//html/Amps/2005-11/msg00263.html (9,167 bytes)

29. Re: [Amps] 220V wiring: Was Question about safety ground connection (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 18 Nov 2005 13:51:03 +0100 (CET)
operating a disconnect device.< Unless it operates at a reasonably high field strength (at least 10v/m), not only radio amateurs but people living relatively close to an amateur or mobile radio base
/archives//html/Amps/2005-11/msg00294.html (9,972 bytes)

30. Re: [Amps] *** SPAM *** Re: 220V wiring: Was Question about safetyground connection (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 18 Nov 2005 17:29:13 +0100 (CET)
That is an argument for no electricity at all. Like the Amish - I doubt many of them get electrocuted. 73 Peter SM/G3RZP _______________________________________________ Amps mailing list Amps@contest
/archives//html/Amps/2005-11/msg00306.html (7,486 bytes)

31. Re: [Amps] *** SPAM *** Re: 220V wiring: Was Question about safetyground connection (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 19 Nov 2005 13:31:59 +0100 (CET)
Not quite. There were deaths reported from the 32 volts used in certain American country areas before WW2. Ouch! bad pun. 73 Peter G3RZP _______________________________________________ Amps mailing l
/archives//html/Amps/2005-11/msg00335.html (7,989 bytes)

32. [Amps] Better electrical safety? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 19 Nov 2005 13:43:24 +0100 (CET)
A problem with a 1kHz supply would be stopping it getting into audio systems in radio, TV etc, as well as phones. Then there's the problem of 'singing' motors and transformers and even flourescent li
/archives//html/Amps/2005-11/msg00336.html (6,695 bytes)

33. Re: [Amps] hit a wall on bi-directional couplers (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sun, 20 Nov 2005 12:30:15 +0100 (CET)
I found that an easier way to make a high power dual directional coupler is the old 'monimatch' SWR bridge approach. Here you have a mainline (which I did with a 50 track on PC board, and two adjacen
/archives//html/Amps/2005-11/msg00366.html (13,576 bytes)

34. Re: [Amps] 2 kW amp project (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sun, 20 Nov 2005 12:35:08 +0100 (CET)
There's an interesting article on a 1500 watt Class E amp in the latest QEX. Looking at it, the thing is that by the time you've got the mechanics done (including a fearsome output transformer with s
/archives//html/Amps/2005-11/msg00367.html (6,899 bytes)

35. Re: [Amps] 2 kW amp project (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 21 Nov 2005 09:36:30 +0100 (CET)
The article in QEX was not a simple multi band device, although I suppose it could eventually get to that. It uses a lot of cheap FETs, and goes up to 7 MHz. Going up to 28MHz with cheap FETs may not
/archives//html/Amps/2005-11/msg00394.html (10,425 bytes)

36. Re: [Amps] FL-21200B (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 6 Dec 2005 13:45:37 +0100 (CET)
right to 6 or 7 on the scale brought up a nice little purple arc between the plates of the loading cap.< Certainly sounds like parasitics to me. Have you checked the original parasitic suppression re
/archives//html/Amps/2005-12/msg00039.html (6,754 bytes)

37. Re: [Amps] help diagnosing a bad 8450a probe ? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 9 Dec 2005 13:34:13 +0100 (CET)
like wave. This probe actually works, however due to the fault it has a phase frequency error< Have you checked the four Schottky diodes in the sampler? I've had funny answers like yours when one of
/archives//html/Amps/2005-12/msg00102.html (7,210 bytes)

38. Re: [Amps] help diagnosing a bad 8450a probe ? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 9 Dec 2005 20:40:17 +0100 (CET)
As Steve says, getting diodes from the same batch will probably do it. It's just that matched diodes come from about the same place on the wafer: it is not uncommon to get a variation across a wafer
/archives//html/Amps/2005-12/msg00108.html (8,516 bytes)

39. Re: [Amps] Antenna traps (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 15 Dec 2005 09:16:18 +0100 (CET)
balanced L network tuner is that if it turns out that a reactance arcs or melts down, retrofitting a more capable L or C does not require bringing down the antenna.< However, the classic parallel or
/archives//html/Amps/2005-12/msg00178.html (8,515 bytes)

40. Re: [Amps] *** SPAM *** Re: Antenna traps (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 16 Dec 2005 09:38:51 +0100 (CET)
Rubbish. Do the math. The Q is the sq.rt of the impedance ratio -1. So the bigger the impedance transformation, the higher the working Q. In any two variable system, Qw is an uncontrolled variable. A
/archives//html/Amps/2005-12/msg00195.html (7,600 bytes)

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