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References: [ +from:Peter_Chadwick@mitel.com: 967 ]

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381. SV: [AMPS]Plate choke at the antenna end instead? (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 11:27:35 -0000; antenna This appeared in Pappenfus' book back in 1964, and I started that discussion in a letter to Pat many years ago now. The problem is that the tuning caps now have to be rated for at least twice; /archives//html/Amps/2000-03/msg00618.html (10,165 bytes)
382. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 13:12:02 -0000; 1. Unless the tests are done the same way, they may be measuring different things. 2.It can be quite frightening to measure the differences between equipments off the line and see the variations in p; /archives//html/Amps/2000-03/msg00621.html (8,411 bytes)
383. [AMPS] Rocky Point effects (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 15:21:09 -0000; OK, that's one of the definitions that I know for the parallel tuned circuit. It's not a definition I like, but given that's the one you're using, I agree. 73 Peter G3RZP -- FAQ on WWW: http://www.co; /archives//html/Amps/2000-03/msg00626.html (8,249 bytes)
384. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 15:23:37 -0000; Somehow, Richy, I rather figure that you are by no means alone with that fear! Me too. 73 Peter G3RZP -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Submissions: amps@contesting.com Administra; /archives//html/Amps/2000-03/msg00628.html (8,478 bytes)
385. [AMPS] Chokes (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 15:52:15 -0000; Very true. I've seen a ferrite cored plate choke used in a commercial 100 watt 2-6146PA. It was rapidly changed in production to a conventional 1 millihenry RFC because: a. that was cheaper b. it per; /archives//html/Amps/2000-03/msg00629.html (8,681 bytes)
386. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 16:35:15 -0000; I'm not sure price comes into it......I don't think they exist with enough bits at enough accuracy. The only real advantage I can see is the controlled group delay for data modes. But I don't see why; /archives//html/Amps/2000-03/msg00631.html (9,684 bytes)
387. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 17:09:23 -0000; I'm told it's good. How good, I don't know. 24 bits sounds good, but I guess it's at low frequency. Figure you want one bit toggling on internal noise, and two bits at the top end to handle the fact; /archives//html/Amps/2000-03/msg00633.html (9,903 bytes)
388. FW: SV: [AMPS]Plate choke at the antenna end instead? (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Mon, 13 Mar 2000 17:17:34 -0000; -- FAQ on WWW: http://www.contesting.com/ampsfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.con; /archives//html/Amps/2000-03/msg00635.html (9,049 bytes)
389. SV: [AMPS]Plate choke at the antenna end instead? (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 14 Mar 2000 09:10:00 -0000; much >greater performance than the 7 element chebyshev design You get about 30dB of second harmonic attenuation in a pi with Q =12, another 30dB is all you need at the most. This means a fairly simpl; /archives//html/Amps/2000-03/msg00654.html (8,498 bytes)
390. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 14 Mar 2000 13:29:21 -0000; In which case, one might ask what the point of the DSP is! Desirably, it could well be argued that the first IF should be low enough (1.4 - 10MHz) that the first mixer is followed by the 500 (or 250H; /archives//html/Amps/2000-03/msg00661.html (10,009 bytes)
391. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 14 Mar 2000 14:12:52 -0000; Yes. To be precise, the phase of the waves making up the flattened envelope are shifted relative to each other, thus modifying the resultant envelope. A bit like the effects of FM through a bandpass; /archives//html/Amps/2000-03/msg00664.html (9,357 bytes)
392. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Tue, 14 Mar 2000 14:15:39 -0000; It's also really good for removing the heterodynes from the tuner uppers! Why does the DXpedition transmit frequency always automatically become the international tune up frequency? 73 Peter G3RZP --; /archives//html/Amps/2000-03/msg00665.html (9,220 bytes)
393. [AMPS] HV rectifier for 4-400 amplifier (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 08:13:45 -0000; I would still recommend a fairly large MOV across the primary of the transformer to snub the worst spikes on the mains, but parallel resistors aren't needed. 73 Peter G3RZP -- FAQ on WWW: http://www.; /archives//html/Amps/2000-03/msg00724.html (7,522 bytes)
394. [AMPS] Re: New G2DAF amplifier information (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 08:48:57 -0000; I have a feeling that a lot depends on the tube(s) used: effectively, they have to be very linear as a screen modulated AM tube at the PEP output required. 73 Peter G3RZP -- FAQ on WWW: http://www.co; /archives//html/Amps/2000-03/msg00725.html (9,610 bytes)
395. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 09:07:20 -0000; I think the noise performance is different because the AF DSP filters will have their noise floor determined by the receiver, and thus the noise input likely to be a long way above the floor of the D; /archives//html/Amps/2000-03/msg00726.html (9,412 bytes)
396. [AMPS] Re: New G2DAF amplifier information (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 09:49:22 -0000; Or if the regulation of the RF drive voltage was poor, or if the grid bias shifted when grid current was drawn. if I think the answer to that is that distortion is reduced in gg because of negative f; /archives//html/Amps/2000-03/msg00727.html (10,426 bytes)
397. [AMPS] HV rectifier for 4-400 amplifier (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 10:01:44 -0000; depends on leakage reactance. For the minimal cost, it's worthwhile. If my power company was like Pacific Graft and Extortion, I'd want all the protection on the supplies that I could get! 73 Peter; /archives//html/Amps/2000-03/msg00730.html (7,664 bytes)
398. [AMPS] Receiver performance (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 12:38:03 -0000; sound >design principles - e.g. proper gain distribution, then it will work. As Shakespeare said 'Aye, there's the rub!' I quite agree, Mike. Unfortunately, I guess the hype is overdone. For relative; /archives//html/Amps/2000-03/msg00738.html (9,640 bytes)
399. [AMPS] Re: Variable Screen Voltage! (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 15:03:01 -0000; not mpg If you go back to my favourite work (Pappenfus et al) he goes into this into some detail. He says 'tetrode tubes can be used in cathode-driven amplifiers. The power gain is considerably highe; /archives//html/Amps/2000-03/msg00743.html (8,331 bytes)
400. [AMPS] Re: New G2DAF amplifier information (score: 1): Author: Peter_Chadwick@mitel.com (Peter Chadwick); Date: Thu, 16 Mar 2000 15:14:33 -0000; Tom has some very good points. Personally, the G2DAF is not an approach I would use, but it can be made to work. My feeling is that some tubes work better in that circuit than others; the screen grid; /archives//html/Amps/2000-03/msg00744.html (10,724 bytes)

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