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References: [ +from:Jim.thom@telus.net: 1396 ]

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381. [Amps] Silver plated Cu strap sources? (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Wed, 7 Dec 2011 22:07:13 -0800; Surplus Sales of Nebraska McMaster Carr Check with Georgia Copper ... they may be able to outsource the plating, or tell you where to go (well, to get the copper plated that is!). 73 Rick NM3G [franc; /archives//html/Amps/2011-12/msg00071.html (9,248 bytes)
382. Re: [Amps] 2 x 3-500Z filament choke + 30/60/80A fil chokes (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Thu, 8 Dec 2011 03:18:49 -0800; tiny little things, just .25" diam x 40mm long, and not made from type 33. Amidon sells .5" x 7.5" rods in only type 61 and type 33. [$20.00] I got the 8" long type 43 rods from SSON several years ag; /archives//html/Amps/2011-12/msg00072.html (11,539 bytes)
383. [Amps] Warm up and on time question... (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 13 Dec 2011 18:44:35 -0800; Hello, I have an AL-82, my habit is to turn it on, allow it to warm for about 5 minutes prior to use, use the amp, then turn it back off. Sometimes I find that I will be using the amp again within 10; /archives//html/Amps/2011-12/msg00107.html (8,971 bytes)
384. [Amps] Is after-powerdown cooling desirable? (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Mon, 19 Dec 2011 21:25:48 -0800; I'm very surprised to hear this. Here's a counterargument: since the internal filament, cathode, and grid structures of an external anode tube dissipate very little heat, compared to the anode itself; /archives//html/Amps/2011-12/msg00151.html (10,196 bytes)
385. [Amps] Linear amplifier tuning (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Wed, 21 Dec 2011 08:52:04 -0800; The discussion about tuning would not happen if we all still used o'scopes with a trapezoid pattern. On such a pattern you can clearly see "flat topping" when the output loading cap is too tight, a s; /archives//html/Amps/2011-12/msg00176.html (11,627 bytes)
386. [Amps] DX-3 PRICE REDUCED FOR CHRISTMAS (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Sun, 25 Dec 2011 16:06:39 -0800; Emtron DX-3 is being offered to those who appreciate the extra headroom of real QRO. This will create band openings or let you dominate a frequency with ease. This is the one that many of the big gun; /archives//html/Amps/2011-12/msg00215.html (7,919 bytes)
387. [Amps] Fwd: Linear Amplifier Tuning---PROPERLY! (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 27 Dec 2011 08:27:33 -0800; I fail to see how having spurious sidebands at -20, -30, -40?or whatever makes the?????????????? Signal wider.? The sidebands are still there regardless of final?suppression level. IMD is caused by n; /archives//html/Amps/2011-12/msg00224.html (10,779 bytes)
388. [Amps] Fwd: Linear Amplifier Tuning---PROPERLY! (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 27 Dec 2011 08:47:07 -0800; Here's more about IMD than you may want to know... I used to work with very low IMD amplifiers for the cellular industry and spent a lot of time studying IMD sources and means of control. I learned t; /archives//html/Amps/2011-12/msg00225.html (16,755 bytes)
389. [Amps] Fwd: Linear Amplifier Tuning---PROPERLY! (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Thu, 29 Dec 2011 22:21:46 -0800; Just think what the bands would sound like if we were still using SSB rigs from the 60's<:-)) Even the Collins and Hallicrafters were not all that great. There were exceptions, but not many. Tx's....; /archives//html/Amps/2011-12/msg00279.html (10,115 bytes)
390. [Amps] Length of coax from xcvr to amp affecting input swr. (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Sat, 31 Dec 2011 04:40:50 -0800; With short length's of coax, [no more than aprx 3'], the input swr between either my FT-1000-D or my FT-1000-MK-V... and the input to my Drake L4B is dead flat. Once the coax is lengthened to aprx 6'; /archives//html/Amps/2011-12/msg00288.html (7,609 bytes)
391. [Amps] L4B Plate choke (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Fri, 6 Jan 2012 14:46:41 -0800; Carl: I pretty much reached the same conclusion. I ordered the Ameritron choke from MFJ. I understand that it is a bit too long physically and needs to be shortened a bit (the form - not the coils).; /archives//html/Amps/2012-01/msg00096.html (7,810 bytes)
392. [Amps] IMD (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Fri, 6 Jan 2012 23:02:43 -0800; If and only if, the bandwidth of the baseband signal fed to the modulator is band limited to the width of the main channel (Unless there is a RF BPF further up the chain limiting the transmitted band; /archives//html/Amps/2012-01/msg00098.html (13,930 bytes)
393. [Amps] Safety choke question (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 10 Jan 2012 20:15:16 -0800; So what do you all think about using an RF Parts RFC-3 (225 uh 1.5A 4KV) plate choke as the safety choke for a large HF amp? The supply is 4KV at up to 2A, bridge rectifier with 32uf of filter. Altho; /archives//html/Amps/2012-01/msg00128.html (9,405 bytes)
394. [Amps] Safety choke question (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Thu, 12 Jan 2012 14:38:20 -0800; Hi Jim, I suppose you would like to put that choke across the (50Ohm) output terminal ? Think 225uH is not needed at all to have negligible effect at 160mtrs. I would go for a reasonable sized toroid; /archives//html/Amps/2012-01/msg00136.html (8,304 bytes)
395. [Amps] 15 uh chokes (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Thu, 12 Jan 2012 14:31:36 -0800; Hi all, Alpha shows 15uh chokes in several places in the 78 and after the plate choke in the 76. The choke in my 76 is about 1/4" dia and 3/8"long and has at most 30 turns. It appears to be a simple; /archives//html/Amps/2012-01/msg00137.html (7,695 bytes)
396. [Amps] Safety choke question (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Fri, 13 Jan 2012 20:34:42 -0800; A 1MH 300ma piewound choke should be just fine in normal operation and still give the amps fuse time to react. Just don't use some slow clunky breaker. Carl KM1H a plate block cap let go.... and the; /archives//html/Amps/2012-01/msg00143.html (8,769 bytes)
397. [Amps] Different amp recommendations (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Tue, 7 Feb 2012 22:29:23 -0800; I have doubts about the AL82 doing 1500 watts 100% duty cycle for very long. Knowing the p.s. in that amp you'll be right at its limit, right at the Ip limit of the tubes, right at or a bit above the; /archives//html/Amps/2012-02/msg00056.html (9,763 bytes)
398. [Amps] Different amp recommendations (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Thu, 9 Feb 2012 07:23:41 -0800; Check Palstar and QRO, dont know what their specs are but a 3 holer "export" model should do it. Carl KM1H. it uses the same HV supply ! It will do 3.5 kw out, but the xfmr is maxed to the peg, and t; /archives//html/Amps/2012-02/msg00073.html (9,432 bytes)
399. [Amps] Source for plate xfrmer (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Wed, 15 Feb 2012 06:15:28 -0800; Hello all, Where do you look for a new HV plate transformer these days? I understand Peter Dahl is no longer around. I'm looking for 3000 VAC secondary @ 1+ amp CCS. TIA 73 de Steve, NR4M A 3 kva CCS; /archives//html/Amps/2012-02/msg00170.html (9,427 bytes)
400. [Amps] Bleeders (score: 1): Author: "Jim Thomson" <jim.thom@telus.net>; Date: Fri, 2 Mar 2012 12:42:02 -0800; Why not skip the bleeder entirely, and make a current discharge circuitry when the session is over. If the anode voltage is very high then stack some thyristors and fire them with opto couplers. So w; /archives//html/Amps/2012-03/msg00038.html (8,605 bytes)

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