A comparison of 10 meter verticals using modeling
I decided to test a few versions of popular ten meter verticals using elnec demo to test. I have had trouble in the past trying to convince people I was using a 5/8 ground plane with decent success. And I could see their point as normally a 5/8 ground plane has a fairly high angle of maximum radiation. But a major difference was I have been using 3/4 wave radials instead of the common 1/4 wave versions. I found what I think is the reason I have had fairly good success. But I also found a few things I was doing wrong in earlier versions. I found for maximum gain, I would be better off using 5/8 wave radials instead of the 3/4 wave. I had assumed in the past that being the 3/4 wave radial would be resonant and the 5/8 would not be,that the 3/4 would be better. But modeling this antenna, this doesn't seem to be the case. I found using 5/8 radials and sloping at a steep angle to the ground, would give the most gain. With the antenna acting more as a dual 5/8 collinear than a 5/8 radiator with a 5/8 wave ground plane.
Don't have elnec or eznec? You can download a demo version here at http://www.eznec.com/elnecdem.htm
I will show the plots of the popular 10 meter verticals. All antennas are modeled at the 40 ft level. I'll start with the 1/4 wave ground plane with 4 sloping radials.
This is the elevation plot over average ground with the antenna at 40 feet.
And the azimuth plot showing freespace gain.
And a view of the antenna showing the current distribution
Go to page 2-The half wave vertical
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