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101. Re: Topband: WAS is "Easy?" (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 08 Dec 2006 15:07:27 -0800
Having operated for 50 years from W9 with mediocre antennas and six months from W6 with decent antennas, I have several observations. 1) EU and AF are tough are about as tough from W6 as JA, DS, and
/archives//html/Topband/2006-12/msg00104.html (8,458 bytes)

102. Re: Topband: : KH8Q and band condx (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 12 Dec 2006 10:13:00 -0800
KH8Q was quite readable for at least a half hour last night (around 1000Z) here on the central California coast. Short CQ's followed by short listening intervals, usually just enough for someone to s
/archives//html/Topband/2006-12/msg00136.html (7,355 bytes)

103. Re: Topband: Help with new noise on topband (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 12 Dec 2006 10:18:09 -0800
Based on correspondence on the RFI list, one good possibility is a battery charger. You might consider walking around the neighborhood with an AM radio and use the loopstick to triangulate on the nul
/archives//html/Topband/2006-12/msg00138.html (7,200 bytes)

104. Re: Topband: Twin Lead (Speaker Wire) Loss? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 20 Dec 2006 09:03:05 -0800
Yes, I was going to make the same suggestion. Or even an RG58. Receive antennas are pretty forgiving about loss and even modest impedance mismatch. What you DO want to carry is a selection of ferrite
/archives//html/Topband/2006-12/msg00202.html (8,297 bytes)

105. Re: Topband: location of vertical (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 26 Dec 2006 08:33:57 -0800
My gut feeling and limited experience agrees with yours. Radials address ONLY the efficiency component of how well your antenna works -- that is, they minimize I2R losses. The slope of the ground in
/archives//html/Topband/2006-12/msg00297.html (7,322 bytes)

106. Re: Topband: Core Mix (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 26 Dec 2006 16:14:41 -0800
In general, cores for transformers should have relatively high mu and low loss. #43 material by far the lowest loss, while the other materials all have about twice as much mu. If I had #43 of suitabl
/archives//html/Topband/2006-12/msg00302.html (7,556 bytes)

107. Re: Topband: Question Re: Coax Shield vs. Ground. (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 30 Dec 2006 08:15:20 -0800
As luck would have it, I've been working on a tutorial about RFI, noise suppression, and the use of common mode chokes to decouple feedlines from antennas. It is currently in first draft form, and ca
/archives//html/Topband/2006-12/msg00346.html (7,981 bytes)

108. Re: Topband: RF Ground or Wire to RF Ground? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 31 Dec 2006 20:49:07 -0800
A connection to the earth is immaterial to the operation of radio equipment. It IS important for ANY power system, but ONLY as a disharge path for lightning and other big voltage spikes that may come
/archives//html/Topband/2007-01/msg00000.html (7,144 bytes)

109. Re: Topband: Core Mix Revisited (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 31 Dec 2006 20:55:30 -0800
Lots of answers to your questions in the tutorial that I just put on my website. It's not finished, but far enough along to answer many of your questions. http://audiosystemsgroup.com/RFI-Ham.pdf To
/archives//html/Topband/2007-01/msg00001.html (7,478 bytes)

110. Re: Topband: "Studying the Noise" in CQWW 160 CW (Was: RE:SM2CEW SPfindings) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 01 Jan 2007 21:09:45 -0800
I had exactly that experience with WE3C and K3WW -- Q5 here, but each time I tried, they were calling CQ again before I had finished sending my call. Too bad -- these were 9 point Q's for high power.
/archives//html/Topband/2007-01/msg00019.html (8,374 bytes)

111. Re: Topband: 1.810 BCB interference (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 05 Jan 2007 09:29:08 -0800
Has anyone sent this one to Riley? Jim K9YC _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband
/archives//html/Topband/2007-01/msg00072.html (7,301 bytes)

112. Re: Topband: 1A4A (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 05 Jan 2007 15:00:21 -0800
Yes. Propagation from EU and AF to the west coast of the US tends to be of the "spotlight" variety, to the extent that the path is only workable for 15-20 minutes to a given location, especially if t
/archives//html/Topband/2007-01/msg00074.html (7,524 bytes)

113. Topband: Topband This Morning (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 07 Jan 2007 08:29:17 -0800
Worked T30XX at 1456Z, 23 minutes before my sunrise. He was also spotted by JA. Heard 9M6NA about 1510Z and called for a while, along with several others, but no one got through and he gave up. Jim K
/archives//html/Topband/2007-01/msg00093.html (6,337 bytes)

114. Re: Topband: 1810 Spur (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 07 Jan 2007 08:50:52 -0800
Near Santa Cruz, I hear 1810 strongest on the SE Beverage. Not strong enough to hear much modulation, but fairly consistent, probably ground wave. It's still solid an hour after sunrise. I also hear
/archives//html/Topband/2007-01/msg00094.html (7,792 bytes)

115. Re: Topband: Effect of DC on Ferrite Toroids? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Jan 2007 08:46:49 -0800
You have two very good reasons NOT to worry. First, the toroids see only the DIFFERENCE between the current on the shield and the current in the center conductor, which is zero. Second, the current i
/archives//html/Topband/2007-01/msg00149.html (8,468 bytes)

116. Re: Topband: Effect of DC on Ferrite Toroids? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Jan 2007 09:25:37 -0800
YES! And a LARGE core running near saturation could also introduce distortion -- that is, INTERMOD! This could be a VERY big deal in a voltage balun, because the core carries the entire output of the
/archives//html/Topband/2007-01/msg00153.html (8,491 bytes)

117. Re: Topband: beverage lobes (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Jan 2007 09:39:16 -0800
Yes, and even when you have antennas that you can switch between, it can be tricky to tell whether the difference are caused by selective fading or the characteristics of the antenna. That takes grea
/archives//html/Topband/2007-01/msg00155.html (8,624 bytes)

118. Re: Topband: Stew Perry TBDC changes being considered (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Jan 2007 17:02:03 -0800
The point of the organizing committee is that they are NOT anything approaching equal, because Northern hemisphere winter is a lousy time for 160 in the southern hemisphere. Imagine a 160 contest on
/archives//html/Topband/2007-01/msg00172.html (9,352 bytes)

119. Re: Topband: Best Height Above Ground for a Beverage RX Antenna (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 10 Jan 2007 16:07:50 -0800
Yes. My Beverages are up around 8 ft so that they clear the deer. They're good on 160, OK on 80, and almost useless on 40. 73, Jim K9YC _______________________________________________ Topband mailing
/archives//html/Topband/2007-01/msg00193.html (8,301 bytes)

120. Re: Topband: Best Height Above Ground for a Beverage RX Antenna (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 10 Jan 2007 18:26:26 -0800
Perhaps. They are reversibles, using DXE hardware at both ends, 400 ohm line, switching, and preamp. They're in a redwood forest and the ground is pretty wet, so perhaps the ground is too good. :) Ji
/archives//html/Topband/2007-01/msg00199.html (9,287 bytes)


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