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81. [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/Towertalk/2004-11/msg00568.html (8,873 bytes)

82. Re: [TowerTalk] Halogen Bulbs - 1.8 Mhz RFI (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 25 Nov 2004 14:16:01 -0600
I agree that there are probably switching supplies causing the problem, but I wouldn't give up on fixing the problem without trying. There are three basic ways the RF can get out -- on the power line
/archives//html/Towertalk/2004-11/msg00672.html (8,530 bytes)

83. Re: [TowerTalk] accuracy of antenna analyzers (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 10 Dec 2004 08:11:14 -0600
I have spent a fair number of hours with a CIA-HF, borrowed from another ham, and own an MFJ-259B that I've calibrated per Tom Rauch's applications note. Tom says that the concepts of the two analyze
/archives//html/Towertalk/2004-12/msg00235.html (8,871 bytes)

84. Re: [TowerTalk] Additonal Comm Port (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 13 Dec 2004 09:37:47 -0600
Not always, and not always reliably. Also, there are timing issues associated with USB to serial that can cause certain software not to work with them at all. A Belkin unit borrowed from KK9H to try
/archives//html/Towertalk/2004-12/msg00274.html (8,674 bytes)

85. Re: [TowerTalk] Ferrite- Type 31 Material (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 18 Dec 2004 10:48:02 -0600
I agree with your assessment. In general, you will achieve higher R over the broadest frequency range in the HF spectrum with #31 than with 43, 44, 77, or 78. You can "tune" the peak attenuation by v
/archives//html/Towertalk/2004-12/msg00342.html (7,993 bytes)

86. Re: [TowerTalk] Kinstar (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 23 Dec 2004 23:06:26 -0600
The narrower bandwidth of arrays has to do with geometry (spacing, azimuth, elevation) and phase relationships between the drive to the elements. I wouldn't expect fattening the conductors to have MU
/archives//html/Towertalk/2004-12/msg00464.html (7,916 bytes)

87. Re: [TowerTalk] CommScope coax (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 27 Dec 2004 13:44:35 -0600
It's very good stuff, optimized for very low loss at UHF. NOT very flexible -- this is for permanent install where it won't move. Solid copper center (#10 if I recall correctly), braid plus foil shie
/archives//html/Towertalk/2004-12/msg00522.html (7,976 bytes)

88. [TowerTalk] White Paper On Power and Grounding (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 29 Dec 2004 20:44:11 -0600
Here's a link to a paper I just finished on Power and Grounding for Audio and Audio/Video systems. While some of the material is specific to the needs of those systems, much of it is generic and appl
/archives//html/Towertalk/2004-12/msg00587.html (7,662 bytes)

89. Re: [TowerTalk] 60th Birthday (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 02 Jan 2005 10:20:41 -0600
Yes. One thing that distresses me a lot is seeing so many morbidly overweight guys riding around hamfests in motorized carts/ bikes, etc. because they're too out of shape to walk. And, of course, the
/archives//html/Towertalk/2005-01/msg00019.html (8,161 bytes)

90. Re: [TowerTalk] BANISHMENT FROM TOWER TALK (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 07 Jan 2005 17:08:57 -0600
Rich said he already did that -- see below. Rich also said he made many phone calls that were never returned. So if we accept his story at face value, he did his best. I don't know Rich or Steve. May
/archives//html/Towertalk/2005-01/msg00203.html (9,534 bytes)

91. Re: [TowerTalk] Source for RG6 Coax (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 10 Jan 2005 12:12:59 -0600
A year or two ago, I bought a 1,000 ft spool of RG6 direct from Commscope. As I recall, it was about $110, including shipping from NC to Chicago. What I bought was some very good quad-shield stuff fo
/archives//html/Towertalk/2005-01/msg00295.html (7,805 bytes)

92. [TowerTalk] Re: [RFI] Buying a new TV (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 10 Jan 2005 20:35:44 -0600
Plasmas are well known to generate SERIOUS trash in the ham bands. They are also prone to burn-in. Jim K9YC _______________________________________________ See: http://www.mscomputer.com for "Self Su
/archives//html/Towertalk/2005-01/msg00322.html (7,149 bytes)

93. Re: [TowerTalk] Coax...braid "coverage" at HF. (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Jan 2005 10:28:06 -0600
Unless I'm missing something, the primary issue with braid coverage is leakage at VHF and UHF. Example: you've got an MATV or CATV system -- when operating close to VHF and UHF transmitters, you don'
/archives//html/Towertalk/2005-01/msg00333.html (7,985 bytes)

94. Re: [TowerTalk] Ham radio vs. satellite dishes (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Jan 2005 11:13:07 -0600
I've had a DirectTV dish for at least 5 years, no problems at all. I'm in a Chicago residential neighborhood that is relatively densely populated -- houses on either side of me are 20 ft from my hous
/archives//html/Towertalk/2005-01/msg00340.html (8,712 bytes)

95. Re: [TowerTalk] Station Ground (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 14 Jan 2005 16:55:48 -0600
It's all part of fooling ourselves about the basic physics. The impedance of a conductor at RF is FAR more dependent on its INDUCTANCE than upon its resistance. So the only value of that "beefy" wire
/archives//html/Towertalk/2005-01/msg00509.html (9,841 bytes)

96. Re: [TowerTalk] Station Ground (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 14 Jan 2005 17:45:38 -0600
Huh? Could you please explain exactly why? A circuit diagram might help. Jim _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Wea
/archives//html/Towertalk/2005-01/msg00520.html (9,208 bytes)

97. RE: [TowerTalk] Station Ground (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 15 Jan 2005 14:27:34 -0600
You were experiencing a "pin 1 problem," probably in both the computer and the radio. Nearly all computer sound cards are built with pin 1 problems, and so are nearly all ham rigs. The correct connec
/archives//html/Towertalk/2005-01/msg00572.html (12,166 bytes)

98. Re: [TowerTalk] Station Ground (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 15 Jan 2005 18:38:17 -0600
YES. (All caps for emphasis) In a home, YES. In a building where there may be a transformer to establish a new system, the NEW neutral must be bonded to ground close to that transformer.AND all groun
/archives//html/Towertalk/2005-01/msg00583.html (10,281 bytes)

99. Re: [TowerTalk] Station Ground (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 15 Jan 2005 20:00:03 -0600
I think you mean it uses the shield as the signal return for the mic. The answer is that still connect the shield to the chassis. At audio frequencies, the circuit board will be at ground potential u
/archives//html/Towertalk/2005-01/msg00589.html (10,563 bytes)

100. Re: [TowerTalk] There's 'ground', and then there's 'ground' (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 16 Jan 2005 09:45:34 -0600
itself is usually floating within the housing. That's not necessarily a bad thing -- IF there are two wires connecting the mic element to the transceiver, one going to the "so-called audio ground," a
/archives//html/Towertalk/2005-01/msg00599.html (10,853 bytes)


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