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121. Re: Topband: DX Engineering Preselector (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 24 Aug 2012 16:46:18 -0400; Antennas have a vector sum of all the accumulated signals arriving at any one time. Peak voltages can be very high. For example I can light the filament of a 12V incandescent 50 mA lamp to a red or; /archives//html/Topband/2012-08/msg00295.html (8,154 bytes)
122. Re: Topband: DX Engineering Preselector (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sat, 25 Aug 2012 14:29:35 -0400; All of this obscures the real issue. The real issue is a device that uses back-to-back diodes to limit signals has soft limiting that starts well below the clamp voltage. If the advertised clamping v; /archives//html/Topband/2012-08/msg00305.html (11,375 bytes)
123. Re: Topband: PREAMP/PRESELECTOR (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sat, 25 Aug 2012 14:43:27 -0400; That is a mediocre TOI amplifier for a "line driver" or broadband "booster" application. It is a simple single J310 JFET source follower, and only makes about 5 -15 dBm TOI. That device also has pre; /archives//html/Topband/2012-08/msg00306.html (7,602 bytes)
124. Re: Topband: DX Engineering Preselector (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 26 Aug 2012 11:33:55 -0400; Then you also say: Since you already said you can design, build, and test what you seem to imply are superior devices, why are you asking me to supply you free instructions? That makes no sense, unle; /archives//html/Topband/2012-08/msg00316.html (9,368 bytes)
125. Re: Topband: Using the K2AV folded counterpoise at VK6VZ (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 26 Aug 2012 12:09:55 -0400; Hi Steve, So you had multiple verticals before that disappointed you, always had more success with an Inverted V. Now you have a new antenna in a new spot with a new counterpoise that also, because o; /archives//html/Topband/2012-08/msg00317.html (8,771 bytes)
126. Re: Topband: Wideband Balun...? (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 28 Aug 2012 15:28:15 -0400; Hi Eddy, Why did you decide on a 4:1? Generally a tuner matches a much higher impedance than a 4:1 balun will safely permit, and has the most difficulty with low impedance loads. If you use a 4:1, it; /archives//html/Topband/2012-08/msg00323.html (8,877 bytes)
127. Re: Topband: Topband Digest, Vol 116, Issue 49 (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Wed, 29 Aug 2012 06:46:31 -0400; http://www.w8ji.com/tuner_baluns.htm Apparently the balun's action was never fully thought through before articles suggesting baluns on tuner inputs were published. Everyone just went with off-the-c; /archives//html/Topband/2012-08/msg00331.html (8,201 bytes)
128. Re: Topband: VO1HP FCP Inv L and Kitchen Oven (score: 1): Author: "Tom" <w8ji@w8ji.com>; Date: Thu, 30 Aug 2012 10:23:36 -0400; Hi Frank, When convenient, we often attribute increased problems to better performance without regard to 20 other bad things that could be at work. My wife does that with her occasional crispy black; /archives//html/Topband/2012-08/msg00335.html (8,816 bytes)
129. Re: Topband: 160m from 5X (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 30 Aug 2012 14:45:28 -0400; I have been v QRV from 5X in past 5 years. Returning this Oct for 8 weeks and considering how best to get 160 on the air as it is the only band I have not worked and reckon there must be un-met need!; /archives//html/Topband/2012-08/msg00342.html (8,626 bytes)
130. Re: Topband: Window ? (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 30 Aug 2012 17:25:29 -0400; The last information I had was this 160 meter DX window was no longer in use as a window by a international agreement of amateurs. It previously restricted North Americans from calling CQ DX in it, w; /archives//html/Topband/2012-08/msg00345.html (7,615 bytes)
131. Topband: Small antenna book (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 30 Aug 2012 19:02:02 -0400; While looking for something entirely different, I came across this. I wonder if anyone has this book? Grant, KM5KG, is one of the most experienced broadcast engineers around. http://www.km5kg.com/160; /archives//html/Topband/2012-08/msg00347.html (7,930 bytes)
132. Re: Topband: DX Window (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Thu, 30 Aug 2012 21:10:08 -0400; Out west in flyover country we rue the day. Tom is spot on. I too stay out of 30-35 for CQing so my western brethren can potentially hear something. Very unfortunate to have the 30-35 window, which m; /archives//html/Topband/2012-08/msg00350.html (7,289 bytes)
133. Re: Topband: DX Window (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 31 Aug 2012 11:35:27 -0400; While my humble station & mediocre efforts in the various Topband contests hardly matter much, I try & make it a point to stay off of those "window frequencies", unless I'm responding directly to a D; /archives//html/Topband/2012-08/msg00362.html (7,739 bytes)
134. Topband: Airports (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 31 Aug 2012 13:07:53 -0400; Lucky me there is no "HOA" where I live. Mention HOA and everybody says "huh? No way". I am about 4000 feet from the nearest runway but that is for small aircraft and the 4000 feet is from my home t; /archives//html/Topband/2012-08/msg00364.html (10,329 bytes)
135. Re: Topband: Airports (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 31 Aug 2012 14:55:18 -0400; I have several private messages and some of them tell me that my 4000 foot distance from the side of that runway alone is enough to make it irrelevant. I don't know about the official status of the a; /archives//html/Topband/2012-08/msg00368.html (10,340 bytes)
136. Re: Topband: 1/4" tip/sleeve connectors? (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sat, 1 Sep 2012 21:58:48 -0400; Greetings to the Forum Would like to know if anyone has used this format of connector to move beverage antenna feedline around the shack? While I'm sure that will make someone somewhere happy, that's; /archives//html/Topband/2012-09/msg00005.html (7,859 bytes)
137. Re: Topband: Radial connections (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 2 Sep 2012 09:29:55 -0400; Any comments one way or the other ? Tie the all together at the roof and run one wire up or tie them to the 20 foot pipe at the roof ?>> There is no difference at all in results, provided you make go; /archives//html/Topband/2012-09/msg00008.html (6,997 bytes)
138. Re: Topband: JA's Mr.160m JA3AA SK (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Sun, 2 Sep 2012 13:35:06 -0400; I am sorry for being late to post but I have to tell that Isaji Shima JA3AA who was the father of not only the Japanese 160m but also entire Japanese amateur radio passed away. JA3AA died at the age; /archives//html/Topband/2012-09/msg00010.html (7,697 bytes)
139. Re: Topband: Air core chokes for 160m (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 4 Sep 2012 11:30:24 -0400; I will need to make common mode choke for 160m "T" shape vertical for my club station. I always used to think I should aim at 3000+ Ohms impedance, but lately I found article at http://rudys.typepad.; /archives//html/Topband/2012-09/msg00019.html (9,121 bytes)
140. Re: Topband: Air core chokes for 160m (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Tue, 4 Sep 2012 12:33:18 -0400; Unless the feedline is up in the air, I can't imagine you need anything at all except perhaps some decoupling to prevent common mode noise from reaching the vertical. I'm sure even a minimal impedanc; /archives//html/Topband/2012-09/msg00020.html (9,004 bytes)

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