Description:
Antennas: theory, techniques and construction.
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antenna type question
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Hey all, There was a type of antenna that I remember from when I was a young'un, but I cannot remember the type that it was. It was a directional antenna, and had three vertical sections, I'm assuming they were dipoles, but am not even sure of that. These verticals were arranged in a Y pattern, and were apparently... more »
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Cushcraft MA5B Noise floor?
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If you own or have used the Cushcraft MA5B in the past could you let me know what the noise floor reading is/was and the rough height of your antenna? I know that the noise floor will be different location to location but it will give me some idea of what I should be looking at. I have had mine up for a couple of years now and although the signals... more »
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ANTENNA for R20
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Hi Please advise I need outdoor antenna for my ICOM -R20 (receiver) what model is recommended ? please consider the overload issue I consider Discone antenna . can i use the AH8000? or the MFJ-1868 or DA3200 Thanks !
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J pole question
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I am thinking of making a 2 meter J-Pole from 3/4 or 5/8 copper pipe. Most plans that I can find on the web call for a 58 inch main leg and a 20 inch support below, making the antenna 78 inches or so in height. I want to install it in my attic where I have 66 inches of clear space. Can I cut the lower support leg down to 8 inches without a major... more »
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Stealth Hex Beam
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I'd like to make a steal hex beam antenna for 17 and 15 meters, maybe even 20 meters. My goal is to make it is invisible as possible. Is there any ideas of what type of support poles that would be the lightest? Maybe croppy fishing poles? I'm even thinking of putting this antenna up when I use and and then bring it down in between days when I do not operate.... more »
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Alliance Tenna-Rotor for sale
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I have an Alliance Tenna-Rotor model T-20 with control box for sale. It has about 87 feet of 4 conductor cable that goes with it. It can be viewed at: [link] or [link] I'm asking $30 plus shipping CUS.... more »
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Art's quiet mesh antenna
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Bill wrote: ...Based on his "designs", which don't seem to exist except as whimsical nonsense, I would wager large amounts of cash that you couldn't possibly have a QSO with him. tom K0TAR
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Lossy Coax: how is energy lost ?
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In a lossy coax the lost energy is, I suppose, heating up the dielectric. To try to visualize that I stripped off 30 cm of dielectric from an old RG58 cable and put it in a 900 W 2450 MHz standard microwave oven together with a 100cc cup of water as dummy load. 2 minutes after switching on the water was boiling but the polyethylene was... more »
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Parallel tank circuit
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A tank circuit represents an antenna closed circuit where in the absence of friction shows the action of electric field changing to a magnetic field as a sample of perpetual motion. However perpetual motion does not exist so to account for all forces involved we have to determine the amount of friction. We cannot use a series circuit as we... more »
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