I've used screens when I needed a wide bandwidth ground system, but never
under other conditions.
Adding a screen or preferably, additional short radials at the base will
assist in stabilizing the resistance component of the vertical radiator and
capacitance across the base insulator as ground conditions change due to wx,
seasonal ground moisture, etc. The stabilization effect is probably more
important with directional systems than it is for non-directional radiators
and is common in AM broadcast systems where an array is sited in a flood
plane.
Paul, W9AC
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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