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21. 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)
22. 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)
23. 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)
24. 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)
25. 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)
26. 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)
27. 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)
28. [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)
29. 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)
30. 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)
31. Re: [RFI] My power line noise problems, revisited (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Sat, 07 Feb 2004 14:26:06 -0600; MOV's are, indeed, a potential cause of RFI. Here's how. When it's working properly, an MOV (metal oxide varistor) has the charactistic of conducting above some threshold voltage but being an open ci; /archives//html/RFI/2004-02/msg00048.html (9,584 bytes)
32. Re: [RFI] Help with broadcast interference (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 13 Feb 2004 00:34:52 -0600; Yes, these are some pretty high field strengths. Are you sure they are correctly measured? I suspect they are not. Perhaps your antenna is influencing the measurement. Exactly how far are you from th; /archives//html/RFI/2004-02/msg00078.html (9,617 bytes)
33. [RFI] FCC okays BPL proposal (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 13 Feb 2004 09:36:03 -0600; As a city resident and ong time believer that one should be a good neighbor, and as a ham who believes that much of the fun of operating lies in doing it with lower power, I've never run more than 10; /archives//html/RFI/2004-02/msg00080.html (7,414 bytes)
34. [RFI] Your Bandpass Filters (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Mon, 16 Feb 2004 10:20:44 -0600; Someone pointed me to your webpage for bandpass filters for the ham bands. It looks like some of your products might be useful to me, but there aren't enough specs for me to know. 1. What is the powe; /archives//html/RFI/2004-02/msg00103.html (7,894 bytes)
35. Re: [RFI] another problem solved. (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Tue, 24 Feb 2004 07:29:42 -0600; If he's talking about the GE Super Radio, your story is interesting for another reason. I own several of these radios. While this is an excellent receiver, it is VERY susceptible to noise on the powe; /archives//html/RFI/2004-02/msg00134.html (6,996 bytes)
36. Re: [RFI] TVI on home cinema audio (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Sun, 29 Feb 2004 09:26:54 -0600; Where have ferrites been tried, what specific types, and how have they been used? The basic function of a ferrite in RFI suppression is to turn the cable that you use it on into a choke. At higher fr; /archives//html/RFI/2004-02/msg00150.html (11,289 bytes)
37. Re: [RFI] RFI and Ford Vehicles (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Thu, 25 Mar 2004 22:47:18 -0600; I use my FT100D in my '99 Volvo S80 on 40 through 10 meters at 100 watts. The battery is in the trunk, and I'm powered directly from the battery. The antenna is a Ham Stick on a license plate mount.; /archives//html/RFI/2004-03/msg00118.html (8,584 bytes)
38. Re: [RFI] Quiet Shack PC Systems? (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Thu, 25 Mar 2004 23:00:35 -0600; One footnote to your excellent advice, Dale. If I'm not mistaken, CE compliance is written around the EN55103-1 and -2. The emissions standard is mandatory, however the susceptibility standard is ess; /archives//html/RFI/2004-03/msg00119.html (9,910 bytes)
39. Re: [RFI] Quiet Shack PC Systems? (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Thu, 25 Mar 2004 23:24:11 -0600; Hmmm. Are you putting a choke on the ground lead? Doesn't that prevent the protection it SHOULD provide for HF transients like lightning and power line misbehavior? I can't imagine that being blessed; /archives//html/RFI/2004-03/msg00120.html (9,300 bytes)
40. Re: [RFI] Today's Wall Stree Journal front page article on hams & BPL (score: 1): Author: "Jim Brown" <jimbrown.enteract@rcn.com>; Date: Fri, 26 Mar 2004 16:23:20 -0600; Yes, I think that contesting skills, especially "old school" contesting, can do a lot to build good the skills needed for operation in emergencies. So does running nets and handling traffic (remember; /archives//html/RFI/2004-03/msg00124.html (9,803 bytes)

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