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21. R: [AMPS] Watt meters and PEP (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 14 Jan 2000 13:46:08 -0000; Not strictly true. There are some amateur meters that measure power directly by absorbing it in a load. I think SSB produce one and there are several home made designs. In case anyone is interested,; /archives//html/Amps/2000-01/msg00277.html (9,280 bytes)
22. R: [AMPS] Watt meters and PEP (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 14 Jan 2000 14:46:45 -0000; ? And what was the low freq. limit for the HP 431 thermistor mount? As I recall, it was c. 10MHz. It depends on the model. Below 10 MHz you might as well use a stopwatch. -- FAQ on WWW: http://www.co; /archives//html/Amps/2000-01/msg00282.html (7,900 bytes)
23. [AMPS] AL-80 Excessive Grid Current METER Shunt SCHEMATIC Solved (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 27 Jan 2000 09:09:52 -0000; What was that I said about making sure the reading was real? I have never come across that one before but it is always a good idea to check a meter as what is on the scale and what the current is ca; /archives//html/Amps/2000-01/msg00540.html (7,797 bytes)
24. [AMPS] Trouble shooting 8877 amp (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Wed, 1 Dec 1999 08:13:52 -0000; Maybe the HV has gone away after all. It could be that there is some high resistance in the circuit so as soon as you try and draw any EHT the volts fall rapidly. A burnt out secondary might achieve; /archives//html/Amps/1999-12/msg00000.html (7,170 bytes)
25. [AMPS] Tetrode Amp Help (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 10 Dec 1999 08:26:49 -0000; Do you really need a stabilized screen grid supply? If the g2 voltage follows relatively slowly the envelope of a SSB signal, you should get a only a slow gain variation in the tube??? You have then; /archives//html/Amps/1999-12/msg00081.html (9,130 bytes)
26. SV:SV:SV: [AMPS] Tetrode Amp Help (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Wed, 15 Dec 1999 08:07:38 -0000; then 4x250B's tubes, Down the road of better receivers with lower noise front ends that more easily detect intermods. -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Submissions: amps@contesti; /archives//html/Amps/1999-12/msg00171.html (9,510 bytes)
27. SV:SV:SV: [AMPS] Tetrode Amp Help (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 16 Dec 1999 08:24:13 -0000; Total twaddle. Do you not operate VHF SSB ? Probably not by the sound of this tirade. Maybe you are not in a popular area ? The VHF receive systems used nowadays certainly have lower noise figures t; /archives//html/Amps/1999-12/msg00189.html (9,183 bytes)
28. [AMPS] Max Ep for 3cx800A7? (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 17 Dec 1999 08:31:58 -0000; I think what matters most is what the voltage is when on load. If your amplifier has appropriate flashover protection, which can be as simple as a 50 ohm high power resistor in the EHT line, any fla; /archives//html/Amps/1999-12/msg00204.html (7,825 bytes)
29. [AMPS] 4CX250 in G2DAF Circuit (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 17 Dec 1999 08:36:32 -0000; of distortion How is -22 dB (1/160) within 10% of -25 dB (1/320) ? Surely it is twice as bad ? Besides, it is not the 3rd order product that matters so much, it is the 5th,7th,9th,11th...... -- FAQ; /archives//html/Amps/1999-12/msg00205.html (8,380 bytes)
30. [AMPS] Excessive Grid Current (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Mon, 20 Dec 1999 08:22:27 -0000; instructions You can tell it is not an AL80A as that can't measure more than 300mA. No. Wrong. It should be around 3000 on load for a 3-500Z. You won't get high output at reasonable grid current wit; /archives//html/Amps/1999-12/msg00266.html (7,486 bytes)
31. SV: [AMPS] More and More and More and More - drive derived screen potential (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Tue, 21 Dec 1999 09:48:51 -0000; You have an interesting definition of linear then. An "amplifier for SSB" may not demand constant gain, but by definition, a linear amplifier does. It also requires linear phase but I seldom see a p; /archives//html/Amps/1999-12/msg00309.html (10,483 bytes)
32. [AMPS] K2RIW 432 Mhz Stripline Amplifier (Dec 72 QST) (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Mon, 1 Nov 1999 08:52:40 -0000; The PSU is 2000-2500V at 500mA to 1A for the anode. The screen grid requires a stiff supply at 350V that can source and sink 20mA per valve. Grids are -55ish volts for a standing current of 100mA per; /archives//html/Amps/1999-11/msg00015.html (8,133 bytes)
33. [AMPS] Italians and power? (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Mon, 1 Nov 1999 08:59:50 -0000; I think you USA guys seriously underestimate the level of QRM that is normal in Europe. 40m in particular, being only 100kHz wide, with only half of that available for SSB, has heavy QRM everywhere; /archives//html/Amps/1999-11/msg00016.html (7,576 bytes)
34. [AMPS] Re: Enameled wire size... (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Wed, 3 Nov 1999 08:03:25 -0000; A useful approximation is that 1mm = 40 thou. -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: ow; /archives//html/Amps/1999-11/msg00102.html (7,302 bytes)
35. [AMPS] A look underneath the Ugly amp. chassis. (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Wed, 3 Nov 1999 17:12:33 -0000; It didn't download at all with Netscape. However with IE5 it did. I can't see the parasitic suppressors. What is the specification ? It looks like an 8877. -- FAQ on WWW: http://www.contesting.com/a; /archives//html/Amps/1999-11/msg00110.html (8,395 bytes)
36. [AMPS] A look underneath the Ugly amp. chassis. (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 4 Nov 1999 08:51:29 -0000; No, because it will wreck the regulation. Most amp PSUs use capacative filters after the rectifier to provide the HV supply. A feature of capacative filtering is the high ratio of the peak current s; /archives//html/Amps/1999-11/msg00134.html (9,765 bytes)
37. [AMPS] Capacitors & Resonance (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 4 Nov 1999 09:20:59 -0000; The ideal capacitor for an amplifier ? IT depends what it is for. Quite often, we don't want a capacitor at all. We want some form of DC blocking to stop the EHT appearing at the antenna, or we want; /archives//html/Amps/1999-11/msg00136.html (9,993 bytes)
38. [AMPS] Capacitors & Resonance (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 4 Nov 1999 16:24:28 -0000; It will indeed. It does need to have an appropriate dielectric. would Why ? I think these capacitors have a very low loss factor? -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Submissions: a; /archives//html/Amps/1999-11/msg00147.html (10,014 bytes)
39. [AMPS] Capacitors & Resonance (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Thu, 4 Nov 1999 16:27:00 -0000; It would seem logical Rich. But what happens is that the anode then becomes unloaded at low frequencies, where the gain is often higher. The amplifier takes off at low VHF or worse sets up a resonan; /archives//html/Amps/1999-11/msg00148.html (7,217 bytes)
40. [AMPS] AL1500 (score: 1): Author: mike@g0mjw.freeserve.co.uk (G0MJW); Date: Fri, 5 Nov 1999 08:30:03 -0000; used Rich is probably correct about it being a problem in the valve (tube). However, do check there is nothing wrong in the metering and PSU circuitry. I think a leaky cathode bypass cap might produ; /archives//html/Amps/1999-11/msg00168.html (7,519 bytes)

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