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221. Re: [TowerTalk] Ground resistance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 08 Jun 2006 12:28:59 -0700
Simplicity is good only if it is CORRECT. Simplicity that is wrong leads to (or reinforces) the myriad of misconceptions about the purpose of earth connections. We've all seen posts here and elsewher
/archives//html/Towertalk/2006-06/msg00131.html (10,013 bytes)

222. Re: [TowerTalk] Ground resistance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 08 Jun 2006 13:21:23 -0700
different people. Yes. Our use of the same symbol for earth and signal common has led to many serious misunderstandings. In our work on international standards with the Audio Engineering Society (AES
/archives//html/Towertalk/2006-06/msg00135.html (9,282 bytes)

223. Re: [TowerTalk] Ground resistance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 08 Jun 2006 13:43:19 -0700
Every piece of wire connecting things together is an inductor that stands in the way of effective lightning discharge. The longer the wire, the greater the inductance. When lightning hits, is is quit
/archives//html/Towertalk/2006-06/msg00136.html (10,103 bytes)

224. Re: [TowerTalk] Ground resistance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 08 Jun 2006 22:49:48 -0700
Huh? I suggest you study Ott's discussion on the nature of the field inside a circular shield. Huh? For any coax that your or I would use on a transmitting antenna, this happens BELOW a few kHz. Abov
/archives//html/Towertalk/2006-06/msg00148.html (10,224 bytes)

225. [RFI] Technical Paper on Ferrites (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 15 Jun 2006 13:03:21 -0700
The paper I presented at the NY AES last fall is now on my website for free download. http://audiosystemsgroup.com/AESPaperFerritesASGWeb.pdf Jim Brown K9YC __________________________________________
/archives//html/Towertalk/2006-06/msg00332.html (6,502 bytes)

226. Re: [TowerTalk] Building a Tower Trailer (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 26 Jun 2006 14:53:57 -0700
As it turns out, Kelly and I were together on Field Day, and I helped push it upright (along with 3 other guys, as I recall). It really is a nice, compact, but very solid tower, and I tried to talk h
/archives//html/Towertalk/2006-06/msg00598.html (7,749 bytes)

227. Re: [TowerTalk] CATV & Phone grounds (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Jul 2006 11:55:08 -0700
Yes. If you think of lightning as DC, you're likely to be in serious trouble. IEEE studies show that the energy content in lightning has a broad peak around 1 MHz, with significant content well above
/archives//html/Towertalk/2006-07/msg00344.html (9,692 bytes)

228. Re: [TowerTalk] CATV & Phone grounds (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Jul 2006 22:47:58 -0700
First, think of the current flow in the output stage of any electronic amplifier. The instantaneous current flow has a DC bias -- that is, it is always flowing in the same direction -- but it has str
/archives//html/Towertalk/2006-07/msg00374.html (10,075 bytes)

229. Re: [TowerTalk] SECOND FLOOR SHACK (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 11:40:31 -0700
Yes that, Horsepucky. An earth connection is NOT a sink for noise, and it is a part of an antenna system ONLY when you're not putting the transmitter power into the transmission line of a properly b
/archives//html/Towertalk/2006-07/msg00387.html (9,470 bytes)

230. Re: [TowerTalk] SECOND FLOOR SHACK (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 13:00:40 -0700
The green wire carried from the breaker panel to each branch circuit is what provides AC mains safety. If something fails inside the connected equipment that makes the chassis hot, the green wire pro
/archives//html/Towertalk/2006-07/msg00395.html (8,049 bytes)

231. Re: [TowerTalk] signals on inside of a pipe.. RE: TT SHUTDOWN (was:4 awg copper wire and Amp locks) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 13:09:33 -0700
No. Coax acts as a nearly ideal common mode choke for signal injected end to end. The only component of that common mode signal that shows up between center and shield is the part below about 1 kHz,
/archives//html/Towertalk/2006-07/msg00396.html (10,332 bytes)

232. Re: [TowerTalk] Question on Multiple Inverted L Antennas (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 14:47:33 -0700
Yes. The antenna described in my earlier post, which is somewhere between an inverted L and a top loaded vertical, worked quite well on 80 and 160, but was quite poor on 40. So while a fan would cert
/archives//html/Towertalk/2006-07/msg00404.html (7,565 bytes)

233. Re: [TowerTalk] SECOND FLOOR SHACK (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 19:17:05 -0700
"Supposed" is exactly that -- only in your imagination. There is NOTHING magical about the earth that causes a connection to it to reduce "stray RF" in your shack. You can disagree, but the stuff you
/archives//html/Towertalk/2006-07/msg00418.html (9,119 bytes)

234. Re: [TowerTalk] Ground wire impedance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 19:26:40 -0700
One of the virtues of wide copper strap is that it DOES reduce the inductance as compared to a single conductor. So it is good from both a skin effect and inductance point of view. And it has long be
/archives//html/Towertalk/2006-07/msg00421.html (8,680 bytes)

235. Re: [TowerTalk] signals on inside of a pipe.. RE: TT SHUTDOWN(was:4 awg copper wire and Amp locks) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 12 Jul 2006 23:53:32 -0700
Common mode voltage is that which is equal on the two conductors and induced between one end of the cable and the other. In other words, lightning is lighting up the coax end to end. Yes, and much of
/archives//html/Towertalk/2006-07/msg00438.html (10,750 bytes)

236. Re: [TowerTalk] signals on inside of a pipe.. RE: TTSHUTDOWN(was:4 awg copper wire and Amp locks) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 13 Jul 2006 09:24:29 -0700
Gary, It is clear that you haven't understood a word that I have written, nor do you care to learn anything that isn't already in your head. Thus, I give up. 73, Jim _________________________________
/archives//html/Towertalk/2006-07/msg00450.html (9,862 bytes)

237. Re: [TowerTalk] SECOND FLOOR SHACK (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 13 Jul 2006 09:49:00 -0700
It isn't quite that simple, Bill. Many of us don't have ideal situations for antennas, and we MUST load something as a long wire. At my new QTH in CA, I have nice, nearly ideal, wire dipoles. But at
/archives//html/Towertalk/2006-07/msg00452.html (11,175 bytes)

238. Re: [TowerTalk] Question on Multiple Inverted L Antennas (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 14 Jul 2006 11:07:36 -0700
Your method is certainly one way to do it, but there are far simpler ways. The link below describes the one I think when you say "inverted L." His discussion is quite solid from an engineering point
/archives//html/Towertalk/2006-07/msg00511.html (10,085 bytes)

239. Re: [TowerTalk] K-Factor capacities (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 24 Jul 2006 22:25:26 -0700
K-Factor is a descriptor for the harmonic current drawn by a product, and the ability of power system components to handle harmonic current without overheating. See the Power and Grounding tutorial o
/archives//html/Towertalk/2006-07/msg00751.html (7,256 bytes)

240. Re: [TowerTalk] K-Factor capacities (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 25 Jul 2006 07:25:30 -0700
Thanks, Mike. Jim _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/l
/archives//html/Towertalk/2006-07/msg00755.html (7,377 bytes)


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