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161. Topband: FO/N6JA on Topband (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 26 Aug 2007 07:51:11 -0700
Brad has been pretty active on the HF bands with a pretty good signal for several years now. When I asked several months ago if he wanted to try 160, he replied that he didn't have an antenna up. Wel
/archives//html/Topband/2007-08/msg00110.html (7,240 bytes)

162. Re: Topband: RX Antenna for DXpedition (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 26 Aug 2007 19:04:46 -0700
There are two REALLY good reasons for having directional receive, whether you're on a desert island or not. 1) QRN will often be 10-15 dB louder in one direction than other, and skipping in from grea
/archives//html/Topband/2007-08/msg00119.html (7,905 bytes)

163. Re: Topband: 160m portable operating (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 28 Aug 2007 08:47:29 -0700
I'll strongly endorse the recommendation for a dipole as high as you can get it AND a Tee or inverted L vertical loaded against as many radials as you can muster. ANY dipole you can get up on 160 is
/archives//html/Topband/2007-08/msg00129.html (9,237 bytes)

164. Re: Topband: 160m portable operating (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 29 Aug 2007 20:51:31 -0700
I agree. I described a Tee loaded vertical. Jim _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband
/archives//html/Topband/2007-08/msg00138.html (7,679 bytes)

165. Re: Topband: [TowerTalk] RX 4 square (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 01 Sep 2007 10:38:51 -0700
"Equal" is where the bodies are buried. To understand this, remember that nulls in a pattern (that is, signal rejection) is the result of the cancellation of signals that are equal and 180 degrees ou
/archives//html/Topband/2007-09/msg00002.html (7,938 bytes)

166. Re: Topband: early westcoast -EU prop (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 01 Sep 2007 19:04:32 -0700
For at least a month, it's also been fairly good from the west coast of the US into JA, VK, and ZL for several hours before sunrise, and some of these stations are working another 2,500 miles further
/archives//html/Topband/2007-09/msg00004.html (7,548 bytes)

167. Re: Topband: AIM4170 antenna analyzer (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 04 Sep 2007 15:50:39 -0700
I don't own one, but have done "round robin" testing with several measurement systems of very high impedance components that have pretty low stray capacitance like ferrite chokes. These components ar
/archives//html/Topband/2007-09/msg00015.html (7,689 bytes)

168. Re: Topband: Antenna Advice Plus K9AY Questions (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 07 Sep 2007 08:22:17 -0700
Preamplifiers improve the signal to noise ratio ONLY when the noise that limits your reception is generated within your receiver. This is virtually never the case on the lower frequency ham bands --
/archives//html/Topband/2007-09/msg00031.html (8,090 bytes)

169. Re: Topband: Ground resistance (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 09 Sep 2007 22:09:17 -0700
Yes. His stuff is now in the ARRL Antenna Book, and it's excellent! Jim K9YC _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/ma
/archives//html/Topband/2007-09/msg00052.html (6,881 bytes)

170. Re: Topband: 160m portable operating (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 11 Sep 2007 13:51:53 -0700
The following is very good for the classic case of quarter wave radials. http://www.antennasbyn6lf.com/files/160_m_vertical_measurements.pdf The author, N6LF, wrote the excellent material in recent e
/archives//html/Topband/2007-09/msg00066.html (8,048 bytes)

171. Re: Topband: Beverage feed line...too long? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 18 Sep 2007 04:48:49 -0700
I can't speak for the K9AY (but he's here to speak for himself). For the Beverage, the answer is YES. A choke formed by winding 7-10 turns of the coax through a 2.4 inch diameter toroid of #31, #77,
/archives//html/Topband/2007-09/msg00112.html (7,221 bytes)

172. Re: Topband: Sunday 30-IX-07 Conditions (VE3) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 30 Sep 2007 14:11:12 -0700
It very well may have been long path. I'm in No Cal; I made a half dozen ZS QSO's on 40CW in a week early this Sept, all long path (my Beverages told me so) between 1300Z and 1430Z. During certain mo
/archives//html/Topband/2007-09/msg00170.html (7,766 bytes)

173. Re: Topband: High voltage and coupling from a vertical to adjacentcoax (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 08 Oct 2007 09:52:54 -0700
Your vertical and the feedline to the dipole CAN interact with each other, and the result can be bad. A VERY easy fix is to add a serious common mode choke to the feedline to the dipole near the tran
/archives//html/Topband/2007-10/msg00016.html (7,800 bytes)

174. Re: Topband: Beverages over coral (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 12 Oct 2007 05:04:03 -0700
That is exactly what you would have learned in any textbook on antennas, including the ARRL Antenna Book. 73, Jim K9YC _______________________________________________ Topband mailing list Topband@con
/archives//html/Topband/2007-10/msg00039.html (7,044 bytes)

175. Re: Topband: Boring report (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 12 Oct 2007 11:29:39 -0700
ZL7/SP9PT was working W6/W7 well after sunrise Friday morning, even through lots of JA stations calling. 73, Jim K9YC _______________________________________________ Topband mailing list Topband@cont
/archives//html/Topband/2007-10/msg00042.html (6,906 bytes)

176. Re: Topband: Transceiver for 160 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 18 Oct 2007 20:35:39 -0700
In order of increasing cost: The TS850, a vintage radio with excellent performance can be had at a bargain price used. It lacks a separate RX antenna input, but that can easily be added with a mod th
/archives//html/Topband/2007-10/msg00076.html (8,156 bytes)

177. Re: Topband: Binocular Xfrmr Follow-Up (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Fri, 19 Oct 2007 06:22:24 -0700
Some ferrites are good enough insulators that coils can be wound with bare wire, some are not. 73, Jim K9YC _______________________________________________ Topband mailing list Topband@contesting.com
/archives//html/Topband/2007-10/msg00081.html (7,159 bytes)

178. [TowerTalk] Dielectric Constant of THHN (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 22 Oct 2007 14:55:44 -0700
I use THHN for antenna wire. For purposes of using NEC to design for length, I need the diectric constant of the insulation used in THHN. For #12, I've been using a thickness of 0.0445 inch and const
/archives//html/Topband/2007-10/msg00121.html (7,047 bytes)

179. Topband: (no subject) (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 22 Oct 2007 10:03:18 -0700
The wiring to your ADSL system is probably acting as a receive antenna for your 160M transmitter. Your best solution is probably common mode ferrite chokes on your computer equipment, and maybe also
/archives//html/Topband/2007-10/msg00124.html (7,393 bytes)

180. Re: [TowerTalk] THHN (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 22 Oct 2007 22:27:01 -0700
I'd call that VERY scientific -- you set up a controlled experiment and carefully measured it! The only way to improve your science would be to measure a lot of antennas and a lot of wire types and w
/archives//html/Topband/2007-10/msg00133.html (7,420 bytes)

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