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141. Re: [TowerTalk] Topband: info on radials repartition... (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 13 Apr 2007 13:15:39 -0700
Nulls are created by cancellation of signals that very nearly equal and very nearly 180 degrees out of phase at the point of observation. For the null to be 20 dB deep, the field strength of the two
/archives//html/Topband/2007-04/msg00081.html (8,535 bytes)

142. Re: Topband: sunrise (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 21 Apr 2007 16:27:59 -0700
Yes. It's all in these links. http://en.wikipedia.org/wiki/Twilight http://aa.usno.navy.mil/faq/docs/RST_defs.html 73, Jim K9YC _______________________________________________ Topband mailing list To
/archives//html/Topband/2007-04/msg00096.html (7,092 bytes)

143. Re: Topband: Sunrise times (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 22 Apr 2007 21:20:34 -0700
It also depends on where the darkness is, where there are stations to take advantage of the propagation, and what conditions are like on the other end. I live on the west coast of the US, and also fi
/archives//html/Topband/2007-04/msg00105.html (8,023 bytes)

144. Re: Topband: End off Season?? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 15 May 2007 11:11:55 -0700
Same here, and I hope to be QRV throughout the so-called "off-season" when I can pull myself out of bed. 73, Jim Brown K9YC _______________________________________________ Topband mailing list Topban
/archives//html/Topband/2007-05/msg00048.html (7,459 bytes)

145. Re: Topband: RG-6 Connectors (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 23 May 2007 08:51:23 -0700
Same here. But it is VERY important that the exact version of the T&B connector be the one that fits the coax you are using, and RG6 comes in lots of variations. If it's the wrong one, it may come lo
/archives//html/Topband/2007-05/msg00072.html (7,351 bytes)

146. Topband: Filters for FT1000MP (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 06 Jun 2007 06:55:54 -0700
I've recently acquired a second MP that came with no optional filters. I'll be using this radio mostly for 160 and for serious contesting. I'd like suggestions as to which filters (specific model num
/archives//html/Topband/2007-06/msg00015.html (6,460 bytes)

147. Re: Topband: Thanks for the listening and share of a commonmode current experience (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 09 Jun 2007 20:44:03 -0700
The first place to put a choke is at the point where you want common mode current to be zero -- where the coax connects to the antenna. In general, you want the impedance of that choke to have a very
/archives//html/Topband/2007-06/msg00019.html (8,009 bytes)

148. Re: Topband: Share of a common mode current experience (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 10 Jun 2007 11:11:28 -0700
Sort of. The two currents are more or less independent of each other. See my previous email. Yes. That implies that the common mode RFI is getting into equipment that has pin 1 problems. The chokes a
/archives//html/Topband/2007-06/msg00023.html (11,292 bytes)

149. Re: Topband: Share of a common mode current experience (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 12 Jun 2007 13:16:04 -0700
This is a VERY high price. which of the fair-rite distributors gives the best prices for Try Lodestone Pacific and Kreger. See the distributor's section of Fair-Rite website for contact info. I've do
/archives//html/Topband/2007-06/msg00032.html (12,042 bytes)

150. Re: Topband: "Still life in the band" (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 25 Jun 2007 20:54:20 -0700
Indeed there is still life in the band as long as someone is there to use it. During the All Asia contest a week or so ago, I called CQ for about a half hour before my sunrise. No Asians responded, b
/archives//html/Topband/2007-06/msg00052.html (7,047 bytes)

151. Re: Topband: Waller Flag Antenna (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 17 Jul 2007 08:58:23 -0700
YES! Even though I was able to put in only a few hours on 160 during IARU this past weekend, I worked ZL, KH2, JA, and some east coast stations from Santa Cruz (near San Francisco). My antennas are j
/archives//html/Topband/2007-07/msg00016.html (7,277 bytes)

152. Re: Topband: Extreme directivity (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 23 Jul 2007 08:43:09 -0700
Yes. AND -- pro audio is the world where I work. This ultrasonic concept was demonstrated at least 20 years ago, but I don't know of any use of the technique in real world systems. One of the problem
/archives//html/Topband/2007-07/msg00027.html (8,838 bytes)

153. Re: Topband: JA Recording (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 24 Jul 2007 17:12:01 -0700
YES! Two days ago, I called CQ for a while and worked two JA's (not quite 5,000 miles) and two VK3's (roughly 10,000 miles) in the half hour before 1200Z. Today, VK6ABL answered my CQ about 1240Z (ju
/archives//html/Topband/2007-07/msg00032.html (6,667 bytes)

154. Topband: Update to Tutorial on RFI, Baluns, Audio for hams,and Choke Cookbook (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 25 Jul 2007 18:08:55 -0700
I've just posted a new version of my tutorial on RFI, Ferrite Chokes, Baluns, and audio for hams. It has the same filename as the original, but the title shows Rev 1, 25 Jul 07. The new stuff is prim
/archives//html/Topband/2007-07/msg00034.html (7,230 bytes)

155. Re: Topband: 3B8CF (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 30 Jul 2007 10:24:07 -0700
..so if he only will try his sunrise it can be promising for NA too. He should not rule out his sunset and early evening either, which could work for pre-sunrise on the west coast of the US. I'm near
/archives//html/Topband/2007-07/msg00039.html (7,119 bytes)

156. Re: Topband: 160M_AC_BUZZ (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 10 Aug 2007 12:48:35 -0700
Don't rule out the possibility that it could be a noise-maker in a home or office near you. Examples include battery chargers (for power tools, mobility scooters, etc.), power supplies for consumer e
/archives//html/Topband/2007-08/msg00008.html (7,610 bytes)

157. Re: Topband: Multiple Ground Systems (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 19 Aug 2007 11:50:42 -0700
One of the major shortcomings of the NEC2 engine is how it deals with the earth. The more expensive NEC4 engine is regarded as more accurate. And as the real pros (like W8JI and N6LF) will tell you,
/archives//html/Topband/2007-08/msg00059.html (10,455 bytes)

158. Re: Topband: RX Antenna for DXepedition (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 21 Aug 2007 08:05:52 -0700
Do it by LOTW -- easy and painless if you use one of the logging programs that talks directly to LOTW! I use DXKeeper -- FREEWARE -- to talk to LOTW. It's not even close to being adequate for logging
/archives//html/Topband/2007-08/msg00069.html (7,783 bytes)

159. Re: [TowerTalk] Topband: RX 4 square (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 22 Aug 2007 12:25:48 -0700
YES! And this is NOT trivial! Phase shift in the resulting network (antenna through transformer to transmission line) will add to the delay of the transmission line. The resulting pattern will not be
/archives//html/Topband/2007-08/msg00091.html (7,951 bytes)

160. Re: Topband: RX 4 square (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 23 Aug 2007 08:43:10 -0700
My post was not intended to say that it won't work, only that it can complicate things. :) Which is much of what Tom is saying. Also, remember that Tom is designing commercial products, which need to
/archives//html/Topband/2007-08/msg00099.html (8,605 bytes)


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