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381. Re: [Amps] SB-1000 160 m power down (score: 1): Author: TexasRF@aol.com; Date: Fri, 16 Dec 2011 19:57:33 -0500 (EST); Hi Han, it seems something in the output circuit is changing value. The most likely part is in the plate loading circuit as that is where maximum rf current flows. Many amplifiers switch in extra cap; /archives//html/Amps/2011-12/msg00127.html (9,569 bytes)
382. Re: [Amps] Fwd: Linear Amplifier Tuning---PROPERLY! (score: 1): Author: TexasRF@aol.com; Date: Wed, 21 Dec 2011 20:12:18 -0500 (EST); Hi All, it makes no sense to not peak the tune C as the last step in a matching procedure. The tuning network is fully adjustable, allowing a match from your nominal 50 ohm load to what ever plate lo; /archives//html/Amps/2011-12/msg00185.html (10,061 bytes)
383. Re: [Amps] Is after-powerdown cooling desirable? (score: 1): Author: TexasRF@aol.com; Date: Wed, 21 Dec 2011 20:20:43 -0500 (EST); Hi Charlie, I am in your corner and will continue running the amplifier cooling blower for a couple of minutes after removing plate and filament/heater voltage. This is not illegal or immoral so no t; /archives//html/Amps/2011-12/msg00186.html (12,815 bytes)
384. [Amps] 3CX800 source (score: 1): Author: TexasRF@aol.com; Date: Tue, 3 Jan 2012 21:55:56 -0500 (EST); A friend is looking for a good 3CX800A7. Any recommendations for a source for new or good pulls? 73, Gerald K5GW _______________________________________________ Amps mailing list Amps@contesting.com; /archives//html/Amps/2012-01/msg00037.html (6,614 bytes)
385. Re: [Amps] Stripline design (score: 1): Author: TexasRF@aol.com; Date: Thu, 5 Jan 2012 21:24:32 -0500 (EST); Hi Paul, K1FO has done the work already. Why not use his dimensions for the stripline? Is there a space problem? Adding 3/8" to the short end of the line will have very little effect on the resonant; /archives//html/Amps/2012-01/msg00073.html (10,294 bytes)
386. Re: [Amps] Stripline design (score: 1): Author: TexasRF@aol.com; Date: Thu, 5 Jan 2012 21:41:11 -0500 (EST); Hi Paul, the single tube design has less capacitance at the tube than the dual tube design. The lower the capacitance at the tube anode, the more inductance required to resonate. More inductance equa; /archives//html/Amps/2012-01/msg00075.html (10,520 bytes)
387. Re: [Amps] Stripline design (score: 1): Author: TexasRF@aol.com; Date: Thu, 5 Jan 2012 22:08:10 -0500 (EST); Paul, adding some C at the short end of the stripline will also lower the resonant frequency by simulating a higher tube anode capacitance. This can be done by adding a small piece of stripline mater; /archives//html/Amps/2012-01/msg00078.html (12,237 bytes)
388. Re: [Amps] 432 MHz stripline (score: 1): Author: TexasRF@aol.com; Date: Mon, 23 Jan 2012 22:08:10 -0500 (EST); Hi All, not to be discouraging, but, using a GDO at UHF is going to be an exercise in frustration. When the cavity cover is removed, the frequency of the resonator will change drastically and have no; /archives//html/Amps/2012-01/msg00173.html (10,738 bytes)
389. Re: [Amps] 3cx800a7 Grid Current Problem (score: 1): Author: TexasRF@aol.com; Date: Wed, 25 Jan 2012 21:40:22 -0500 (EST); About a month ago, JE1BMJ reported a similar problem with his SB1000. In his case, the problem was found to be inadequate bypassing of the plate rf choke. Apparently enough rf was reaching the bypass; /archives//html/Amps/2012-01/msg00196.html (9,101 bytes)
390. Re: [Amps] SB-200 (score: 1): Author: TexasRF@aol.com; Date: Thu, 9 Feb 2012 20:37:04 -0500 (EST); This wouldn't be a case of the input switch wafer out of alignment with the output wafer would it? 73, Gerald K5GW In a message dated 2/8/2012 8:33:15 P.M. Central Standard Time, w7why@frontier.com w; /archives//html/Amps/2012-02/msg00082.html (7,873 bytes)
391. Re: [Amps] Grid current protection HELP (score: 1): Author: TexasRF@aol.com; Date: Mon, 13 Feb 2012 21:30:35 -0500 (EST); Rick, that address: members.cruzio.com/~k6xx/radio/76a_prot.pdf does not work for me. Is something missing? 73, Gerals K5GW In a message dated 2/13/2012 6:59:20 P.M. Central Standard Time, n6pe@yahoo; /archives//html/Amps/2012-02/msg00134.html (8,525 bytes)
392. Re: [Amps] Source for plate xfrmer (score: 1): Author: TexasRF@aol.com; Date: Tue, 14 Feb 2012 08:33:26 -0500 (EST); Hi Ian, a third requirement for good regulation is a stiff ac power service. In rural areas this can be a bit of a problem with C filter designs. Can also be a problem in older homes with less than r; /archives//html/Amps/2012-02/msg00147.html (9,344 bytes)
393. Re: [Amps] Source for plate xfrmer (score: 1): Author: TexasRF@aol.com; Date: Tue, 14 Feb 2012 10:54:42 -0500 (EST); I guess there is some electrical code that forbids connecting the 120vac blower between one side of the 240ac line and neutral? I hope this doesn't start another round of ground vs neutral wiring sin; /archives//html/Amps/2012-02/msg00154.html (10,771 bytes)
394. Re: [Amps] Current thinking on HV supply bleeder current? (score: 1): Author: TexasRF@aol.com; Date: Tue, 28 Feb 2012 17:04:16 -0500 (EST); Jim, T=RC is the equation to discharge 65% of the energy. T is seconds, R is ohms and C is farads. Those big wirewound resistors have a voltage rating that should be followed. An over voltage will le; /archives//html/Amps/2012-02/msg00325.html (11,358 bytes)
395. Re: [Amps] Cell phones, digital cameras and RF (score: 1): Author: TexasRF@aol.com; Date: Tue, 6 Mar 2012 08:35:13 -0500 (EST); Hi All, if the phone/camera has issues with rf you have to wonder about long term effects on the operator. One would think that brain tissue is less robust than a cell phone. Scary stuff! 73, Gerald; /archives//html/Amps/2012-03/msg00065.html (10,235 bytes)
396. Re: [Amps] How to know when filter caps begin to fail (score: 1): Author: TexasRF@aol.com; Date: Wed, 28 Mar 2012 22:12:03 -0400 (EDT); Hi Carl, as you know, there are only eight of those filter C's in the Ameritron amps. When AC line voltage gets up around 245vac or so, the unloaded plate voltage gets close to 3600vdc. That leaves v; /archives//html/Amps/2012-03/msg00335.html (11,444 bytes)
397. Re: [Amps] WTB Supplemental Question: E.F. Johnson socket#124-311-100 for Co... (score: 1): Author: TexasRF@aol.com; Date: Tue, 3 Apr 2012 11:35:21 -0400 (EDT); Hi All, correct me if this wrong: The Johnson socket has the same pin out as a compactron socket. An Ebay search for Compactron Socket turns up many of them priced from a couple of $$ up. Seems like; /archives//html/Amps/2012-04/msg00034.html (11,514 bytes)
398. Re: [Amps] Filter Capacitors (score: 1): Author: TexasRF@aol.com; Date: Thu, 12 Apr 2012 23:42:58 -0400 (EDT); Roger, the transformer only delivers current during the time the transformer voltage is greater than the plate voltage. The rectifiers disconnect the transformer when it's voltage falls below the pla; /archives//html/Amps/2012-04/msg00119.html (12,607 bytes)
399. Re: [Amps] Filter Capacitors (score: 1): Author: TexasRF@aol.com; Date: Thu, 12 Apr 2012 23:47:58 -0400 (EDT); Oops, make the connected/disconnected 33 degrees connected and 57 + 90 = 147 degrees disconnected during the half cycle. 73/K5GW In a message dated 4/12/2012 10:43:16 P.M. Central Daylight Time, Texa; /archives//html/Amps/2012-04/msg00120.html (12,768 bytes)
400. Re: [Amps] Filter Capacitors (score: 1): Author: TexasRF@aol.com; Date: Fri, 13 Apr 2012 06:18:29 -0400 (EDT); Yup, connected 66 degrees, disconnected 294 degrees over a full cycle. Same 5.45 ratio for the example given. 73, Gerald K5GW In a message dated 4/12/2012 11:27:21 P.M. Central Daylight Time, k8ri@ro; /archives//html/Amps/2012-04/msg00124.html (8,426 bytes)

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