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Total 523 documents matching your query.

1. Re: [Amps] Tetrodes (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 12 Jul 2005 15:44:37 +0100
Additionally, some tubes (the old 35T comes to mind) have tantalum anodes. Tantalum has the property of absorbing gas when it gets hot, unlike most materials. So tantalum anodes are designed to run h
/archives//html/Amps/2005-07/msg00115.html (8,601 bytes)

2. Re: [Amps] 572B heater voltage? (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 14 Jul 2005 15:37:17 +0200 (CEST)
6.3volts, 4.0.amps 73 Peter G3RZP == Message date : Jul 13 2005, 08:58 PM To : amps@contesting.com Copy to : Subject : [Amps] 572B heater voltage? Anybody know what is the filament voltage/Amperes fo
/archives//html/Amps/2005-07/msg00153.html (7,167 bytes)

3. Re: [Amps] solder vs. High temp. (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 26 Jul 2005 01:46:31 +0200 (CEST)
I use a hand held propane/butane torch to get up to around 700 deg C for silver soldering with what we call Easiflo 2- about 620 deg C melting point. That's about red heat. 73 Peter W6/G3RZP -- Whate
/archives//html/Amps/2005-07/msg00309.html (7,685 bytes)

4. Re: [Amps] Bend allowance (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 4 Aug 2005 10:42:52 +0200 (CEST)
Ian asked: As Will said, use a softer aluminium. Or heat treat what you have. Problem is that that heat treating aluminium is a pretty specialist subject needing good heat control. However, I have su
/archives//html/Amps/2005-08/msg00083.html (8,159 bytes)

5. Re: [Amps] Bend allowance (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 4 Aug 2005 17:39:31 +0200 (CEST)
W0UN commented on aluminium characteristics changing with age. Very true. Generally, I find a bit of the heat treatment works anyway. 73 Peter GW3RZP/P _______________________________________________
/archives//html/Amps/2005-08/msg00097.html (7,552 bytes)

6. Re: [Amps] Amps Digest, Vol 32, Issue 12: Metric system (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 4 Aug 2005 17:43:04 +0200 (CEST)
Georg, A pint is not a pound everywhere. In UK measure, a pint is 20 fluid ounces, not the measly US 16. A most important differenece in buying beer! Personally, I find it easier to handle thousandth
/archives//html/Amps/2005-08/msg00098.html (7,372 bytes)

7. Re: [Amps] Metric system (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 4 Aug 2005 20:09:24 +0200 (CEST)
Personally, I find working to 0.001 inch easier than working to 4 microns. This is because I'm working to a single unit, rather than a number of them. Beer is far better in 20ounce pints than 16 ounc
/archives//html/Amps/2005-08/msg00111.html (7,759 bytes)

8. Re: [Amps] Conversion Nightmare (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 5 Aug 2005 10:07:18 +0200 (CEST)
Getting back to something to do with amplifier building, to my mind, one of the abominations of the metric system is the ISO metric thread. Even the ISO metric coarse is far too fine a thread for man
/archives//html/Amps/2005-08/msg00150.html (8,585 bytes)

9. Re: [Amps] Testing filament xfmr (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 10 Aug 2005 13:31:05 +0200 (CEST)
Simpler is to connect an ampmeter across the secondary, feed the primary from a Variac and wind up the Variac until trhe desired filament current flows. then leave it for a time and see how hot it ge
/archives//html/Amps/2005-08/msg00368.html (7,001 bytes)

10. Re: [Amps] TV sweep tubes and 6146s (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 10 Aug 2005 13:44:01 +0200 (CEST)
Back when I had almost limitless supplies of 6146Bs, I ran a pair at 1200 volts on the plates. They lasted well, provided you didn't run steady carrier, and gave about 180watts PEP out with 3rd order
/archives//html/Amps/2005-08/msg00370.html (8,532 bytes)

11. Re: [Amps] TV sweep tubes and 6146s (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Wed, 10 Aug 2005 16:40:31 +0200 (CEST)
For 400 watts, I think you might get it with 4 6146Bs, with 1400 on the plates. You would need lots of cooling, no speech processing, a pulser for tuning, a big box of spares and no SSTV or RTTY. The
/archives//html/Amps/2005-08/msg00378.html (10,416 bytes)

12. Re: [Amps] Testing filament xfmr (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 11 Aug 2005 14:53:17 +0200 (CEST)
If it doesn't get too hot on open circuit, the iron losses aren't too high. If it doesn't get too hot on short circuit, the copper losses aren't too high. Probability is that it won't get too hot in
/archives//html/Amps/2005-08/msg00406.html (9,471 bytes)

13. Re: [Amps] Step-Starts (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 13 Aug 2005 18:22:53 +0100
I choose a capacitor for the delay on what looks reasonable and leave it to sort itself out.........The delay on the present amp is about 5 seconds: the series resistor is a 50 ohm 200 watt vitreous
/archives//html/Amps/2005-08/msg00466.html (7,525 bytes)

14. Re: [Amps] Silver plating tank hardware (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 19 Aug 2005 08:05:32 +0100
lacquered, it will turn black. You might as well polish the copper (easier is a dip in dilute nitric acid, or even boil in vinegar!), wash well, and then lacquer. If you don't care about the looks,
/archives//html/Amps/2005-08/msg00601.html (7,671 bytes)

15. Re: [Amps] Xmtr output impedance? (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 5 Sep 2005 18:20:21 +0100
I take it that you mean 'optimum load impedance', not actual 'output impedance'? 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.cont
/archives//html/Amps/2005-09/msg00059.html (7,021 bytes)

16. Re: [Amps] 3rd Order IMD (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 22 Sep 2005 20:03:46 +0200 (CEST)
Caveat: Well designed 6146 amps use NFB. Not all of them do..... 73 Peter W6/G3RZP (San Diego this week). _______________________________________________ Amps mailing list Amps@contesting.com http://
/archives//html/Amps/2005-09/msg00293.html (7,425 bytes)

17. Re: [Amps] 4CX1500B (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 22 Sep 2005 21:09:55 +0200 (CEST)
frequency, tune to the fundamental frequency, add attenuation as needed to give the same S-meter reading as before. The # of db of attenuation is how many db down the total IMD is.< Even this depend
/archives//html/Amps/2005-09/msg00296.html (8,408 bytes)

18. Re: [Amps] 4CX1500B (score: 1)
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Fri, 23 Sep 2005 20:07:48 +0200 (CEST)
You still have to set it to around 1.5% of full scale. found by a 2-tone IMD test. Agreed. I use a steady "ahhhhhhhhh". A 2 tone test is a convenient start, A 3 tone test with 2 of the tones very clo
/archives//html/Amps/2005-09/msg00312.html (8,412 bytes)

19. Re: [Amps] 4CX1500B (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 26 Sep 2005 18:44:41 +0100
meter to some level, perhaps c, half-scale. I note the average reading, move to the fundamental frequency, and add whatever attn is needed to achieve the same reading as before. The # of db on the at
/archives//html/Amps/2005-09/msg00325.html (8,133 bytes)

20. Re: [Amps] why not graphite anodes? (score: 1)
Author: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
Date: Thu, 29 Sep 2005 20:26:54 +0100
Electrically, this almost certainly true. But how about price and availability? 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.conte
/archives//html/Amps/2005-09/msg00376.html (7,515 bytes)

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