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221. Re: Topband: Quick question on radials (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 07 Jan 2008 10:01:44 -0800
Based on an excellent piece by N6LF in the ARRL Antenna Book, this is your best option with the length of wire you have. If you have more wire, add more radials, again at that length. If you have a L
/archives//html/Topband/2008-01/msg00071.html (7,866 bytes)

222. Re: Topband: MN8-CX cores (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 11 Jan 2008 05:58:29 -0800
ON4UN is a smart guy, and I'm sure that his recommendations are solid, but he's buying European products that are hard to find in the US. I doubt very seriously that there are any ferrite products we
/archives//html/Topband/2008-01/msg00080.html (7,632 bytes)

223. Re: Topband: FW: MN8-CX cores (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 11 Jan 2008 13:36:27 -0800
Thanks John. The company is new to me. The website lists them at $1 each for 16 pieces, $1.50 each for 4 pieces. These, however, are cores for Beverage transformers. The question I was responding to
/archives//html/Topband/2008-01/msg00083.html (7,886 bytes)

224. Re: Topband: Filters and grounding (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 15 Jan 2008 06:20:50 -0800
That is the "old" way. Bill Whitlock published an AES paper (JAES Jun 1995) that convinced everyone who read it that the proper shield connection for a "one end only" bond is at the SENDING end, not
/archives//html/Topband/2008-01/msg00115.html (11,942 bytes)

225. Re: Topband: Filters and grounding (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 16 Jan 2008 01:23:17 -0800
The pro audio community (which includes people with excellent RF background) has moved well beyond the somewhat limited views of susceptibility cited in your reply. Anyone concerned with these issues
/archives//html/Topband/2008-01/msg00126.html (8,928 bytes)

226. Re: Topband: Filters and grounding (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 16 Jan 2008 07:14:43 -0800
For those of you unable (or unwilling) to chase down Whitlock's JAES papers, here's a link to the pdf of a tutorial that I presented to an IEEE EMC conference three years ago. It includes a presentat
/archives//html/Topband/2008-01/msg00127.html (9,942 bytes)

227. Re: Topband: Cable Modems (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 17 Jan 2008 20:47:05 -0800
Two suggestions. First, I hear that there are commercial filters that fix this pretty good on 160. Second, you might try a multi-turn ferrite choke designed for 160M, following the guidelines (and me
/archives//html/Topband/2008-01/msg00135.html (7,195 bytes)

228. Re: Topband: radials under Beverage (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 23 Jan 2008 22:38:53 -0800
YES. Beverages work on the principle that the ground under them is lossy. Add radials and it becomes less lossy, so the Beverage degrades. 73, Jim K9YC _______________________________________________
/archives//html/Topband/2008-01/msg00167.html (7,343 bytes)

229. Re: Topband: radials under Beverage (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 24 Jan 2008 09:39:56 -0800
George, Let me expand on my earlier comment. The purpose of radials is to reduce losses in the earth under a vertical. It matters less what directions those radials run than the quantity of them and
/archives//html/Topband/2008-01/msg00172.html (8,547 bytes)

230. Re: Topband: Ant Analyzer Assistance request -- funky readings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 24 Jan 2008 11:46:53 -0800
Like most (all?) analyzers at this price level, the MFJ has problems in the presence of strong RF. Go to http://www.fcc.gov/mb/audio/amq.html and enter the lat/lon coordinates and a distance of 20 mi
/archives//html/Topband/2008-01/msg00173.html (8,752 bytes)

231. Re: Topband: radials under Beverage (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 24 Jan 2008 13:29:21 -0800
I would study resources like the W8JI and N6LF websites, and the better ham texts (ARRL Antenna Book, etc.). 73, Jim K9YC _______________________________________________ Topband mailing list Topband@
/archives//html/Topband/2008-01/msg00176.html (7,830 bytes)

232. Re: Topband: Ant Analyzer Assistance request -- funky readings (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 25 Jan 2008 09:33:15 -0800
Careful! First, the impedance of a series resonant circuit isn't "zero" at resonance, it's some "low resistance." Second, it's only "low resistance" that frequency. At the frequency where you're meas
/archives//html/Topband/2008-01/msg00183.html (8,955 bytes)

233. Re: Topband: Noise Radiation from Long Cables (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 29 Jan 2008 16:36:54 -0800
I suggest you study my material on common mode current and RFI. EARTH is NOT a sink into which noise is poured, to disappear forever. What was probably happening is that the generator was putting com
/archives//html/Topband/2008-01/msg00198.html (8,959 bytes)

234. Re: Topband: OZ7YY QSL's (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 04 Feb 2008 11:09:19 -0800
On Sun, 03 Feb 2008 21:58:34 -0600, Mike(W5UC) & Kathy(k5MWH) Watson wrote: One can certainly understand and respect Finn's preference for paper cards. What gets expensive is the green stamps needed
/archives//html/Topband/2008-02/msg00015.html (7,808 bytes)

235. Re: Topband: DSL line disconnect on topband (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 06 Feb 2008 08:55:01 -0800
It is a Netgear problem. Lots of hams have wireless hubs with no RFI from their transmitters. It is the WIRED connections to the router (including possibly the power supply) and/or its poor shielding
/archives//html/Topband/2008-02/msg00031.html (8,051 bytes)

236. Re: Topband: RX power splitter (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 07 Feb 2008 09:15:10 -0800
MiniCircuits has exactly what you want, in MANY variations. Very good quality stuff. They sell through their own rep network, I think. I've used them in pro applications to split antennas for wireles
/archives//html/Topband/2008-02/msg00041.html (8,141 bytes)

237. Re: Topband: Daytime Propagation (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 11 Feb 2008 13:26:17 -0800
This is the operative sentence, and it is QUITE clear in its meaning. Those who don't understand it don't WANT to understand it. Jim Brown K9YC _______________________________________________ Topband
/archives//html/Topband/2008-02/msg00067.html (7,290 bytes)

238. Re: Topband: Re Birdies (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 21 Feb 2008 10:05:45 -0800
There are very effective ways to use wireless and protect yourself from interlopers. A very simple one is to use authentication by MAC address. Go into the setup menu of the router, find the advanced
/archives//html/Topband/2008-02/msg00104.html (8,525 bytes)

239. Topband: f Re: Need More Help Getting rid of Router Birdies (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 21 Feb 2008 10:45:07 -0800
Several comments. 1) #43 is NOT a good choice for suppressing RFI below 40 Meters. It is VERY effective at 40M and above. For RFI on 80M, 160M, and the AM broadcsat band, you need #31. If your proble
/archives//html/Topband/2008-02/msg00105.html (14,800 bytes)

240. Re: Topband: VP6DX Very Loud (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 26 Feb 2008 13:25:34 -0800
That's one very important element. A second is taking both transmitting and receiving antennas seriously and cranking power into them. A third is BEING THERE. Remember all the activity we heard durin
/archives//html/Topband/2008-02/msg00129.html (7,291 bytes)


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