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References: [ +from:Peter.Chadwick@zarlink.com: 335 ]

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201. [AMPS] Choke input PS question (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Mon, 22 Oct 2001 16:39:19 +0100; I'm not sure if that happens with a tuned choke (I don't like calling it 'resonant' because we've seen it had better not be!) but those spikes are why you need a good big capacitor on the output to k; /archives//html/Amps/2001-10/msg00439.html (9,142 bytes)
202. [AMPS] resonant choke PS (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 23 Oct 2001 16:13:34 +0100; What happens to the PIV on the rectifiers? One would expect the high voltage caused by the resonance to push them hard. Puzzled 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submis; /archives//html/Amps/2001-10/msg00447.html (6,845 bytes)
203. [AMPS] Henry 1KD5 Rectifier question (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 30 Oct 2001 09:58:12 -0000; project one I've heard this too. One story is some form of electrolysis. I think that a more likely problem would be caused by metal migration. Metal migration in ICs halves for every 12 degree decre; /archives//html/Amps/2001-10/msg00498.html (10,412 bytes)
204. [AMPS] Henry 1KD5 Rectifier question (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Wed, 31 Oct 2001 11:00:03 -0000; flow I suppose it would have some effect, but as the cathode current (as opposed to the filament current) is so much less, I doubt it would make much difference. Reversing the polarity of the filamen; /archives//html/Amps/2001-10/msg00500.html (9,185 bytes)
205. [AMPS] Henry 1KD5 Rectifier question (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Wed, 31 Oct 2001 11:33:25 -0000; they still need to draw a lot of current if they're not to introduce cathode bias! 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative req; /archives//html/Amps/2001-10/msg00502.html (8,534 bytes)
206. [AMPS] Henry 1KD5 Rectifier question (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Wed, 31 Oct 2001 13:39:28 -0000; I suspect more failures are caused by the stresses when you first switch on and the current is many times normal. Thus the high leakage reactance power transformer is useful. Interestingly, even indi; /archives//html/Amps/2001-10/msg00504.html (8,738 bytes)
207. [AMPS] 4CX800 Idle Current a bit high (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Wed, 31 Oct 2001 13:49:20 -0000; Whatever it takes. The exact voltage will depend on the gm of that particular tube: I'd expect somewhere around the -60 to -68 volt range. You adjust the bias to get it right - unless you've a number; /archives//html/Amps/2001-10/msg00506.html (7,480 bytes)
208. [AMPS] test - plse ignore (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Fri, 14 Sep 2001 14:28:19 +0100; -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com; /archives//html/Amps/2001-09/msg00244.html (6,477 bytes)
209. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Mon, 17 Sep 2001 17:40:01 +0100; There's a complication in that you have to compare apples with apples, and not potatoes. Plus the fact that the grounded cathode tetrode with NFB can do as well as the triode. Like all these things,; /archives//html/Amps/2001-09/msg00286.html (7,774 bytes)
210. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 07:58:19 +0100; As evidenced by the published test figures on, for example, the TS2000. Interesting, since modern MOSFET PA's are supposedly very linear. However, is not that (amplifier IMD less than transceiver IMD; /archives//html/Amps/2001-09/msg00295.html (10,414 bytes)
211. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 10:46:45 +0100; Is it, I wonder, the result of the shortage of RF engineers that we hear so much about? Although the reality is not so much a shortage of engineers, but a shortage of ones prepared to work for the sa; /archives//html/Amps/2001-09/msg00297.html (8,729 bytes)
212. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 12:38:17 +0100; Any exciter where that is the case requires adjustment - preferably with a 14 pound sledgehammer, followed by a can of petrol and a lighted match. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.; /archives//html/Amps/2001-09/msg00300.html (8,597 bytes)
213. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 13:05:59 +0100; I think Maurie and Jon have hit it: these days, RF is a 'carrier' for the digital stuff, and the competent engineers go elsewhere - or retire. Last week I was on a CAD course. Naturally, I argued whe; /archives//html/Amps/2001-09/msg00303.html (8,857 bytes)
214. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 13:28:44 +0100; get out of If you take a 3/2 power curve for your 'perfect' triode, and do the analysis, you see the 3rd order products dipping and then getting worse as power increases. Eimac did this in 'care and; /archives//html/Amps/2001-09/msg00306.html (9,713 bytes)
215. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 13:53:21 +0100; According to Pappenfus, a test with very closely spaced tones (<50Hz) will do it - but you need a spectrum analyser with very good resolution. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com; /archives//html/Amps/2001-09/msg00308.html (8,591 bytes)
216. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 14:34:37 +0100; The idea of the FCC rules is to prevent the manufacture and use of amplifiers on CB. So any amateur can build one amplifier per year for bands below 144MHz without getting type acceptance. To get typ; /archives//html/Amps/2001-09/msg00310.html (9,205 bytes)
217. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 15:32:56 +0100; Quite a good test is to use wide band noise, too. A notch in the frequency response of the noise allows the IMD to be measured under relatively realistic conditions. This technique used to be used on; /archives//html/Amps/2001-09/msg00315.html (8,818 bytes)
218. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 15:59:18 +0100; Quite possibly! You know as well as I do that given the ghost of a chance, a spectrum analyser will lie like a personnel manager (and they make politicians look honest!) A DSP based spectrum analyser; /archives//html/Amps/2001-09/msg00319.html (8,791 bytes)
219. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Tue, 18 Sep 2001 16:07:39 +0100; Alternatively, if it's just non-coherency you want, they tell me 75m SSB in the US or 80m over here is just the thing. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: am; /archives//html/Amps/2001-09/msg00320.html (8,563 bytes)
220. [AMPS] IMD (score: 1): Author: Peter.Chadwick@zarlink.com (Peter Chadwick); Date: Wed, 19 Sep 2001 07:47:35 +0100; That means that your wideband noise doesn't have a low frequency component, so isn't the required 'noise'. An appreciable LF component is required. The illusion on 40dB may be there that it is 'in ch; /archives//html/Amps/2001-09/msg00340.html (10,639 bytes)

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