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21. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 22 Dec 2003 16:34:35 -0600; The shielding enclosure of most electronics is a reasonable ground reference. A 747 has no connection to earth, but the shielding on its wiring works just fine. And even if that receiver had a 2-pron; /archives//html/RFI/2003-12/msg00049.html (8,123 bytes)
22. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 22 Dec 2003 18:03:54 -0600; I can do both. It's called "shield-current-induced noise," (SCIN). It was first described by Neil Muncy (ex-W3WJE) in an AES paper in 1994, based on research he did only at audio frequencies. I've do; /archives//html/RFI/2003-12/msg00054.html (12,535 bytes)
23. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 22 Dec 2003 19:15:57 -0600; If you go high enough in frequency it appears to do exactly what you think. It's just that it appears to simplify to that at a higher frequency than you think. Yes. When I have time, I intend to look; /archives//html/RFI/2003-12/msg00058.html (9,814 bytes)
24. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 03:17:08 -0600; No, I'm sorry that I can't do that. When you publish with AES, they have distribution rights. I don't get any of the money. I can promise you that the papers are worth your time and money if you are; /archives//html/RFI/2003-12/msg00060.html (8,709 bytes)
25. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 09:29:33 -0600; I'm sorry that you feel that way. I paid about $80 for my copy of Henry Ott's book, a bit less (per book) for "Antennas" by John Kraus, for the IEEE Emerald Book and Green Book, and for Tsaloviovich'; /archives//html/RFI/2003-12/msg00064.html (8,905 bytes)
26. Re: [RFI] shielding question (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 10:17:44 -0600; I do not. These papers are not math-filled tomes. They were written for audio engineers, many of whom have limited understanding of RF issues, so there is much in them of a tutorial nature. There's n; /archives//html/RFI/2003-12/msg00066.html (9,164 bytes)
27. Re: [RFI] Paying for information (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 11:34:30 -0600; Thanks to the efforts of some of my compadres on the AES Standards Committee, AES Standards can be downloaded at no cost. That wasn't true before our involvement. By contrast, many standards bodies t; /archives//html/RFI/2003-12/msg00072.html (10,481 bytes)
28. Re: [RFI] Eliminating TVI (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 12:03:39 -0600; Sounds like a really severe case! I suspect either power line or antenna line coupling, and I suspect the filters you are using are ineffective below 20 meters. The 43 material is primarily a VHF mat; /archives//html/RFI/2003-12/msg00074.html (8,093 bytes)
29. Re: [RFI] Paying for information (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 13:51:09 -0600; I have stated that it is common for foil/drain shielded cable to couple sufficient AM broadcast RF or RF from a 100 watt HF ham transmitter onto the signal pair for detection to occur in commonly use; /archives//html/RFI/2003-12/msg00078.html (7,876 bytes)
30. Re: [RFI] Paying for information (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 23 Dec 2003 22:07:55 -0600; The Journal of the AES is in most good technical libraries. The convention preprints are not. Northwestern University is the only library I know of in Chicago (where I live) that allows the general p; /archives//html/RFI/2003-12/msg00087.html (9,988 bytes)
31. RE: [RFI] shielding answer (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Wed, 24 Dec 2003 13:53:50 -0600; Thanks for sharing all of this. I don't remember if you mentioned what the original loudspeaker cable was, but unshielded twisted pair is known to be far superior to zip cord in rejecting RF. I've ne; /archives//html/RFI/2003-12/msg00092.html (9,494 bytes)
32. Re: [RFI] shielding answer (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Wed, 24 Dec 2003 16:05:15 -0600; Not really. Consider the near field of a 1/4 wave resonant antenna. Near the feedpoint, the magnetic field will be quite strong, but the electric field will be quite small. At the far end, the conver; /archives//html/RFI/2003-12/msg00096.html (9,670 bytes)
33. Re: [RFI] Eliminating TVI (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 26 Dec 2003 17:37:51 -0600; Yes. Not necessarily -- this burst detector would also be looking at a composite video signal (i.e., plain ordinary video on coax). Agreed on all of the above, except that my weapon of choice would b; /archives//html/RFI/2003-12/msg00100.html (10,605 bytes)
34. Re: [RFI] Eliminating TVI (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 29 Dec 2003 00:33:28 -0600; Well, maybe, and maybe not. Consider that many shacks are located such that a "ground" conductor will have considerable inductance and be some significant fraction of a wavelength at many frequencies; /archives//html/RFI/2003-12/msg00113.html (11,002 bytes)
35. RE: [RFI] Plastic parabolic reflector (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 06 Jan 2004 10:56:48 -0600; You've piqued my interest. How do you plan to use it? As a reflector for a mic to listen for arcing? Jim K9YC _______________________________________________ RFI mailing list RFI@contesting.com http:; /archives//html/RFI/2004-01/msg00009.html (7,116 bytes)
36. Re: [RFI] RFI from Horizonal Sweep (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Wed, 07 Jan 2004 07:44:21 -0600; Ferrites turn the wires into RF chokes, so they essentially eliminate the connection of the shield to ground. That sounds more like a way to render the the shield useless, not increase its effectiven; /archives//html/RFI/2004-01/msg00013.html (7,265 bytes)
37. Re: [RFI] LSI (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 09 Jan 2004 10:12:16 -0600; As Tom, W8JI, noted recently in an excellent post, there's only so much you can do with ferrites based on their impedances and impedances of the circuits into which they are inserted at the frequency; /archives//html/RFI/2004-01/msg00022.html (8,222 bytes)
38. [RFI] KW Twin Lead (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 13 Jan 2004 19:42:47 -0600; I've got most of a spool of some old Belden 8210 72 ohm transmitting twin lead that I've had in my basement for quite a few years. It's discontinued, and I can't find any data for it. Can anyone tell; /archives//html/RFI/2004-01/msg00040.html (7,253 bytes)
39. RE: [RFI] CQ-BPL (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 30 Jan 2004 13:17:08 -0600; I don't find this series of suggestions all that bad. While I don't condone deliberate interference, the practitioners and users of BPL need to learn as early as possible that it is quite vulnerable; /archives//html/RFI/2004-01/msg00066.html (8,464 bytes)
40. Re: [RFI] Experience with RF-INQUIRY Hi-Q Chokes? (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 02 Feb 2004 10:00:20 -0600; Tom has hit this nail straight on the head (as usual). The problem is comparable to measuring the filtering characteristics of power line filters -- neither the standards for measurement nor the avai; /archives//html/RFI/2004-02/msg00007.html (9,261 bytes)

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