One of four Force12 EF-180BV shortened 80m verticals. These linear loaded verticals are approximately 34 feet high and have 64 ground radials per vertical. The array is fed using a COMTEK ACB-80 hybrid coupler. As you can see the array is installed in a heavily wooded area but still performs well with typical F/B of 20-30 dB.
This array was originally installed in the fall of 2000 with four elevated radials/vertical and upgraded the following year to eight. In the summer of 2003 the elevated radial system was replaced with a ground mounted radial system. Under each vertical there are (64) 1/4 wavelength radials for a total of almost 3 miles of wire!
While the new ground system was a lot of work its reduced the dump power from 4-6% to about 2% (see configuration data table) and the array is much more balanced which has increased its useable BW. It also looks like the angle of takeoff has been reduced as well.
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Min Dump
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10% Dump (low)
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10% Dump (high)
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Useable BW
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NE
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2.0% (3.810 MHz)
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3.766 MHz
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3.868 MHz
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102 KHz
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SE
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1.7% (3.810 MHz)
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3.768 MHz
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3.874 MHz
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106 KHz
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SW
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2.0% (3.810 MHz)
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3.767 MHz
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3.874 MHz
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107 KHz
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NW
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1.7% (3.810 MHz)
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3.760 MHz
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3.875 MHz
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107 KHz
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