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21. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 19 Dec 2005 12:32:08 -0500
Hi Marv, Gee, that feed forward correction method sounds like something that would be ideal for the FT-1000D. As you said, it could be later moved from rig to rig too. So far all I've seen on the web
/archives//html/Amps/2005-12/msg00261.html (10,202 bytes)

22. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 19 Dec 2005 16:29:00 -0500
Karl-Arne, OK on the caution needed regarding obtaining these high IMD numbers. Good advice, OM. I would say that the level of distortion I heard when listening to the 5mW level coming out of the FT-
/archives//html/Amps/2005-12/msg00266.html (10,404 bytes)

23. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Tue, 20 Dec 2005 14:46:03 -0500
I called some ham friends looking for 4CX-350's drivers for the tetrode linear project. One of the guys has some 8560A's, with sockets, heatsinks, etc. that I can swap some stuff for. These are the c
/archives//html/Amps/2005-12/msg00275.html (10,400 bytes)

24. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Wed, 21 Dec 2005 11:52:49 -0500
That's the info I needed, Steve! -30 db IMD at 300+ watts. Yes, as you said, the 8560's [4CX-250's] will be used as class A voltage drivers putting out barely a watt or two, and 30 volts of swing. Th
/archives//html/Amps/2005-12/msg00283.html (13,190 bytes)

25. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Wed, 21 Dec 2005 12:06:49 -0500
Gary, Yes, I've read that too, but then I've read the opposite.. That statement above would make my question about using a chain of GG tubes running at 1/10th reduced ratings a poor idea. I'm a litt
/archives//html/Amps/2005-12/msg00285.html (11,197 bytes)

26. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Thu, 22 Dec 2005 12:35:33 -0500
Very interesting comments. It certainly IS an eye opener when you see what each driver plate dissipation needs to be for an all class A chain. But an easy way to maintain high IMD figures. I'm consid
/archives//html/Amps/2005-12/msg00296.html (11,988 bytes)

27. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Thu, 22 Dec 2005 14:17:48 -0500
Please disregard my question below: "Would there be a major disadvantage to running the whole tetrode chain in GG with standard voltages on the grid and screen? It seems it would be much easier to ta
/archives//html/Amps/2005-12/msg00297.html (12,006 bytes)

28. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Thu, 22 Dec 2005 20:29:31 -0500
Just to keep the reflector updated with info... I received a few private emails regarding using a chain of hi mu GG tubes in cascade. The general consensus is that it was not a very good idea. One re
/archives//html/Amps/2005-12/msg00300.html (9,780 bytes)

29. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Tue, 27 Dec 2005 16:10:06 -0500
Hi Bob, Thanks for the suggestion. You make a good point of possibly eliminating the 6146 pre driver. I thought about that myself, but didn't have enough knowledge to know if I would have enough gain
/archives//html/Amps/2005-12/msg00348.html (10,868 bytes)

30. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Wed, 28 Dec 2005 18:08:20 -0500
Hi Marv, The 75M mono-bander: Well, it looks like your original driver from that Hughes amplifier with the 6146 driving the 4CX-250 is still the best way to go. Thanks for clearing up the stage gain
/archives//html/Amps/2005-12/msg00369.html (11,233 bytes)

31. Re: [Amps] Westinghouse BC Ammeter QX-37 (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 9 Jan 2006 11:39:26 -0500
Generally, on most bands, we can "hide" in the band crud when the amp is between -25 to -30db 3rd order. This includes bands like 40M at night, 20M during a contest, 160M when the band is QRN noisy,
/archives//html/Amps/2006-01/msg00273.html (11,093 bytes)

32. Re: [Amps] Westinghouse BC Ammeter QX-37 (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 9 Jan 2006 12:03:11 -0500
Hi Bill, I'll encourage the other guys answer the finer details of how NFB works... But, for every DB of negative feedback, you get a db of IMD improvement. And also, for every db of negative feedba
/archives//html/Amps/2006-01/msg00277.html (11,013 bytes)

33. Re: [Amps] Clean -vs- Unclean (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 9 Jan 2006 13:11:48 -0500
-- Some very good points in that last post and truth about the real world radios out there! What stands out to me is the Class A mode of the FT-1000MP and later rigs, etc. Their 200W amplifier can b
/archives//html/Amps/2006-01/msg00287.html (9,258 bytes)

34. Re: [Amps] Clean -vs- Unclean (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 9 Jan 2006 13:22:18 -0500
Here's a coincidence! I just received an email from a buddy who is considering buying an FT-1000MP. They are being closed out and discontinued according to a salesman. Here's the salesman's comments
/archives//html/Amps/2006-01/msg00289.html (8,672 bytes)

35. Re: [Amps] Clean -vs- Unclean (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Mon, 9 Jan 2006 14:30:10 -0500
-- Vely, bery interesting, Peter! I passed that info along to my friend who is considering the MP. With what particular rig was this a problem? I am also thinking of selling my highly modified FT-10
/archives//html/Amps/2006-01/msg00297.html (9,127 bytes)

36. Re: [Amps] Components Causing Distortion in Amplifiers (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Tue, 10 Jan 2006 00:00:54 -0500
Hi Colin, That is some interesting info! I was not aware of the need for audio bypassing in the areas you mentioned. Also, I have always wondered about shorting the final's tank coil for band changes
/archives//html/Amps/2006-01/msg00311.html (12,355 bytes)

37. [Amps] Source for 4-1000A Clips to hold chimney/tube? (score: 1)
Author: "Tom Cathey" <K1JJ@comcast.net>
Date: Fri, 13 Jan 2006 19:59:32 -0500
Does anyone have for sale, or know of a source for the little gold clips that screw down to the chassis and hold a 4-1000A chimney and tube in place? [they also ground the tube collar - 4 used per tu
/archives//html/Amps/2006-01/msg00377.html (7,198 bytes)


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