8 Jul 2012 17:06
Re: Topband: Loss comparison between two antennas
Jim Brown <jim <at> audiosystemsgroup.com>
2012-07-08 15:06:33 GMT
2012-07-08 15:06:33 GMT
On 7/8/2012 7:54 AM, Steve Flood wrote: > This resonates the antenna below 1.8Mhz with a feedpoint > Z of 37 +j245. Matching is through an L-network. My intention was to > increase radiation resistance and efficiency and move the current maxima > away from the feedpoint and to the center of the vertical for lower takeoff > angle. About five years ago, I increased the top-loading on my 86 ft Tee vertical so that the feedpoint impedance was 50 + J xxx, and tuned it with series capacitance. It works "well," but there's no good way to compare it to anything, other than, perhaps, a model. Like you, I have a lot of radials on the ground. A couple of years ago, I added a second vertical wire, spaced from the first by 6-8 inches, wired in parallel at both ends. The second conductor increases the SWR bandwidth nicely. 73, Jim K9YC
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