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341. Re: [Amps] "10 Meter Ban" to be lifted ... (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 15 Oct 2006 05:17:15 -0400; OK, I see your point. Good point Gary and one that almost everyone misses. Conventional thought is the peak to average power ratio is only about 2:1. While that may be true for processed speech (eve; /archives//html/Amps/2006-10/msg00134.html (10,244 bytes)
342. [Amps] PEP power.. (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 15 Oct 2006 21:42:17 -0400; Lou, You probably know this but it is worth saying again. PEP is the peak of the RF envelope, or the short term peak "RMS" or work power. It isn't a one RF cycle peak, and it certainly isn't the pea; /archives//html/Amps/2006-10/msg00153.html (9,066 bytes)
343. Re: [Amps] PEP power.. (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 16 Oct 2006 05:00:08 -0400; peak envelope power (of a radio transmitter): The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope tak; /archives//html/Amps/2006-10/msg00161.html (8,850 bytes)
344. Re: [Amps] PEP power.. (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Mon, 16 Oct 2006 14:02:24 -0400; ALL the power is the effective heating or work power, and since the RF cycle is a sine wave it is derived from the RMS voltage and/or current. If we take the peak voltage of the RF sinewave (it is a; /archives//html/Amps/2006-10/msg00181.html (10,574 bytes)
345. Re: [Amps] Fixed Transmitting Capacitors: REVISITED (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 17 Oct 2006 19:32:32 -0400; The reason ceramic transmitting doorknobs have such high negative temperture coefficient is the expansion of the ceramic, not the design. They would like to have a NP0 or temperature stable type ava; /archives//html/Amps/2006-10/msg00191.html (10,390 bytes)
346. Re: [Amps] Testing amp with no air flow (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 19 Oct 2006 13:30:39 -0400; Tubes can overheat with just filament power although it takes a while. A few minutes probably won't hurt but I'd sure keep my eye on the seal temperature. 73 Tom ____________________________________; /archives//html/Amps/2006-10/msg00201.html (8,014 bytes)
347. Re: [Amps] More information for "What NOT to buy".. (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 24 Oct 2006 12:30:53 -0400; People look at this the wrong way. When we look at a collection of components and think they have a power limit we often misjudge it. There are two limits to a tank circuit, current (heat) and volta; /archives//html/Amps/2006-10/msg00275.html (10,616 bytes)
348. Re: [Amps] More information for "What NOT to buy".. (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 24 Oct 2006 12:39:00 -0400; The switch in the SB220 is exactly the same wafer style and manufacturer as in many Dentrons and Amp Supply amps of similar operating HV. That switch is good for normal mistuning at about 3000 volts; /archives//html/Amps/2006-10/msg00276.html (10,422 bytes)
349. Re: [Amps] 3CX3000 tuned input calibration (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 24 Oct 2006 19:43:34 -0400; would be necessary. I merely hooked up the 50 resistor to the output of the tuned circuit and fed power to the input and watched the SWR as I adjusted the trimmers(one on each side of the toroid indu; /archives//html/Amps/2006-10/msg00280.html (6,935 bytes)
350. Re: [Amps] 3CX3000 Tuned Input Calibration (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 26 Oct 2006 13:34:14 -0400; Don't let anyone tell you slapping a resistor from the output of the network to ground simulates the load by the tube. It doesn't. You initially got lucky Bob. It fell apart on 160 because of the fi; /archives//html/Amps/2006-10/msg00286.html (8,904 bytes)
351. Re: [Amps] High Temp Silicon Rubber -- Where to buy? (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 31 Oct 2006 05:20:03 -0500; Someone else already gave the answer, but I'll repeat it. McMaster Carr sells the exact material he was looking for. http://www.mcmaster.com/ 73 Tom _______________________________________________ Am; /archives//html/Amps/2006-10/msg00321.html (7,738 bytes)
352. Re: [Amps] Henry 3K trouble (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Wed, 1 Nov 2006 08:17:41 -0500; Brian, That is almost always a short from the negative rail of the HV to ground at the filter capacitor side of the metering circuit. What that will do is place the grid meter in parallel with the p; /archives//html/Amps/2006-11/msg00004.html (8,236 bytes)
353. Re: [Amps] DIN Connector (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Wed, 1 Nov 2006 18:31:45 -0500; Unless you are running 10kW plus on high duty cycle modes or you just want to impress people, I'd suggest you just use a good quality UHF connector. A good quality UHF connector will handle 10kW and; /archives//html/Amps/2006-11/msg00019.html (7,458 bytes)
354. Re: [Amps] Henry 3K trouble (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Wed, 1 Nov 2006 18:34:32 -0500; The fault current only goes one direction. The negative rail can only elevate more and more negative if the HV faults. I never protect meters or rails for the other direction because I never turn my; /archives//html/Amps/2006-11/msg00020.html (8,583 bytes)
355. Re: [Amps] 4CX1500 class AB1 vs. AB2 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Wed, 1 Nov 2006 22:30:03 -0500; What particular 4CX1500 do you have? The A or the B? There is a huge difference. The 1500B generally should be used at zero or very near zero grid current. You better not run the 4CX1000A anything b; /archives//html/Amps/2006-11/msg00029.html (7,840 bytes)
356. Re: [Amps] 4CX1500 class AB1 vs. AB2 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 2 Nov 2006 11:04:23 -0500; Ian GM3SEK Why would that be a disaster Gary? It is a disaster when people have a loose grid supply and use them in what they think is AB1. Virtually every exciter on market today has severe oversho; /archives//html/Amps/2006-11/msg00037.html (8,787 bytes)
357. Re: [Amps] 4CX1500 class AB1 vs. AB2 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 2 Nov 2006 12:16:55 -0500; A grid driven tetrode has the most severe problems with IM perfromanc. Although they could be designed with controlled negative feedback, most are not. That being the case many or most are already p; /archives//html/Amps/2006-11/msg00039.html (9,442 bytes)
358. Re: [Amps] 4CX1500 class AB1 vs. AB2 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 2 Nov 2006 19:27:44 -0500; A sharp transient is quickly gone and has little average power. Until we clip it. The worse thing we can do is turn that sharp transient into a long period of non-linerarity as the grid voltage pump; /archives//html/Amps/2006-11/msg00044.html (9,850 bytes)
359. Re: [Amps] Class C amp for RTTY contesting... (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 2 Nov 2006 19:39:02 -0500; I have a few questions about this idea: What would be needed to convert a "traditional" linear (AL-1200, AL-1500, L-4B, TL-922, etc) to strictly Class C Too much work. Is there a specific tube (or tu; /archives//html/Amps/2006-11/msg00045.html (8,558 bytes)
360. Re: [Amps] 4CX1500 class AB1 vs. AB2 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 3 Nov 2006 02:40:32 -0500; The rig had severe overshoot into a dummy load, antenna, amplifier, or anything else placed on the output. I'm not alone in seeing that problem with 775's, and many (if not most) rigs have that prob; /archives//html/Amps/2006-11/msg00051.html (9,091 bytes)

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