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41. Re: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 08 Nov 2004 22:36:12 -0600
You have encountered an example of what my friend Bill Whitlock (www.jensentransformers.com) calls "audio jewelry." It is sold to gullible "audiofools" (the mis-spelling is intentional) with a load o
/archives//html/RFI/2004-11/msg00012.html (9,218 bytes)

42. RE: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Nov 2004 14:47:59 -0600
Ah, but you understand the laws of physics rather well! You've correctly identified it as 100% serpent lubricant. Jim _______________________________________________ RFI mailing list RFI@contesting.c
/archives//html/RFI/2004-11/msg00013.html (7,062 bytes)

43. Re: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Nov 2004 16:52:49 -0600
First, audio cables are too short and the wavelengths of audio signals too long for transmission line behavior of audio cables to be a factor. The mfrs of exotic cables would have you believe that is
/archives//html/RFI/2004-11/msg00014.html (10,937 bytes)

44. Re: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Nov 2004 18:27:16 -0600
West Penn, Gepco, and Belden all make stranded twisted pair cable in the #12 - gauge range. You can also "roll your own" out of stranded THHN from Home Depot by sticking it in a twist drill. And you
/archives//html/RFI/2004-11/msg00015.html (8,770 bytes)

45. RE: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 10 Nov 2004 10:35:31 -0600
Read the parts of my original post about the woofer "flopping around" if there is too much resistance between it and the power amp. It is NOT transmission line behavior at all, but it IS a simple, lu
/archives//html/RFI/2004-11/msg00017.html (8,935 bytes)

46. Re: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 10 Nov 2004 19:19:26 -0600
You might want to take another look at this, Tom. I just did, looking at the circuit analysis of some of the line filters in my junkbox. It never occurred to me to try it, but I think Dave is right -
/archives//html/RFI/2004-11/msg00026.html (9,950 bytes)

47. Re: [RFI] NOISE GADGETS (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 10 Nov 2004 20:50:58 -0600
In a central office or studio, that's absolutely true. But if I'm miles of wire from the central office it isn't. I strongly agree that the filtering is a completely different ballgame if you're tryi
/archives//html/RFI/2004-11/msg00030.html (8,528 bytes)

48. Re: [RFI] DSC Alarm Panel 75 Meters/False Alarms (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 17 Nov 2004 07:16:26 -0600
Common split cores are optimized for 50 MHz and us, and would not be expected to be effective at 4 MHz. Your tone sounds defensive -- it should not be. DSC is the guy with the problem, and THEY shoul
/archives//html/RFI/2004-11/msg00040.html (10,205 bytes)

49. Re: [RFI] DSC Alarm Panel 75 Meters/False Alarms (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 17 Nov 2004 09:25:21 -0600
It depends on how the RF is getting in. If it is a pin 1 problem, it probably would not fix it. If it was differential mode, it probably would. To understand why, I'll review what "the pin 1 problem"
/archives//html/RFI/2004-11/msg00044.html (11,185 bytes)

50. Re: [RFI] DSC Alarm Panel 75 Meters/False Alarms (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 17 Nov 2004 11:07:49 -0600
A bypass cap on the signal conductor to the chassis does not help a pin 1 problem. A bypass cap from the shield to the chassis may help, hurt, or not be enough. It would help by lowering the Z of the
/archives//html/RFI/2004-11/msg00046.html (9,810 bytes)

51. [RFI] Conductive Concrete and Grounding (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 19 Nov 2004 08:43:05 -0600
Gentlemen, I'm doing some reasearch for an applications note I'm preparing on power and grounding for audio and video systems, and wanted to mention the use of a Ufer as a ground electrode. This got
/archives//html/RFI/2004-11/msg00055.html (8,651 bytes)

52. Re: [RFI] Ethernet RFI Elimination? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 01 Dec 2004 18:37:14 -0600
Hi Eric -- sorry for the late response -- I've been on the road. 14,030, 21,052, and the bottom 20 kHz of 10 meters are some that I have identified. Shielded CAT5 is NOT necessary, and will probably
/archives//html/RFI/2004-12/msg00000.html (7,641 bytes)

53. Re: [RFI] routers & wall warts (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 04 Dec 2004 11:55:00 -0600
Your conclusions are in agreement with mine that this is the dominant mechanism for the best behaved products. Some products may also radiate directly due to a combination of poor circuit layout and
/archives//html/RFI/2004-12/msg00009.html (7,847 bytes)

54. [RFI] re: It's the old story of peeling the onion -- (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 05 Dec 2004 17:47:47 -0600
Thanks for all of this excellent advice, and I can't find fault with any of it. It's part of the next layer of the onion in my shack. But I suspect that after taking care of my own dirty laundry, I'l
/archives//html/RFI/2004-12/msg00011.html (8,370 bytes)

55. RE: [RFI] re: It's the old story of peeling the onion -- (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 05 Dec 2004 22:43:43 -0600
I can't take credit for the onion analogy, but it is an excellent one. I think it might be from the late Dick Heyser, the father of Time Delay Spectrometry (TDS), whose "day job" was at Jet Propulsio
/archives//html/RFI/2004-12/msg00013.html (8,030 bytes)

56. Re: [RFI] Core for common-mode choke? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 13 Dec 2004 21:59:47 -0600
I have several thoughts. First, you left out some very important information about your problems. It is impossible to consider the design of any filtering without knowing the answers to both of those
/archives//html/RFI/2004-12/msg00016.html (9,233 bytes)

57. [RFI] RE: Topband: FT-240-77 Toroid Impedance R + jX Components (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 03 Jan 2005 17:18:51 -0600
The difference is that the Fair-Rite curves you are looking at are for different materials that have peaks at much higher frequencies. My data and Michael's data correlate quite well, and my data has
/archives//html/RFI/2005-01/msg00003.html (7,088 bytes)

58. [RFI] Fwd: Re: [TenTec] RE 28.634 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 06 Jan 2005 09:38:55 -0600
Gentlemen, The following post from the TenTec reflector is interesting because it illustrates the obvious need for a list of common "birdie" frequencies and the equipment that produces them. I've edi
/archives//html/RFI/2005-01/msg00006.html (10,710 bytes)

59. Re: [RFI] Buying a new TV (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Jan 2005 08:37:16 -0600
That is true. And selling them for residential use is a violation of FCC rules. But thanks to our downsized Federal government, FCC rules don't get enforced. Thank you, Mr. Reagan. Jim Brown K9YC ___
/archives//html/RFI/2005-01/msg00012.html (7,545 bytes)

60. Re: [RFI] TVI (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jan 2005 09:01:19 -0600
I've been doing considerable research on that, and can offer this advice. The Fair-Rite 2.4" O.D. toroids are listed in the catalog with #43, #78, and #61. I've also just received (and measured) samp
/archives//html/RFI/2005-01/msg00021.html (7,748 bytes)

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