I'm installing a vertical antenna in back yard. About 20 feet in height and using 1 counterpoise wire 16 feet for 20 meters. Does installing two or more counterpoise wires help?
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$\begingroup$ Hi Jim, and welcome to this site! Can we assume that your counterpoise wires are elevated and not on the ground? $\endgroup$– Mike WatersCommented Feb 15, 2020 at 16:32
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1$\begingroup$ Yes the counterpoise is insulated off the ground about 1.5 - 2 ft. $\endgroup$– user16431Commented Feb 15, 2020 at 18:58
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2 Answers
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As a start, below is a NEC analysis of the system described in the OP.
The horizontal radials lie along the +Y or the + and -Y axes.
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A single counterpose wire makes the antenna pattern directional, usually in the direction of the counterpose. Two or more counterposes in a symmetrical arrangement makes the antenna pattern more horizontally omnidirectional.
The asymmetry of a single counterpose also makes it more difficult to arrange the feed line so that the antenna's radiation pattern doesn't couple to the feedline and generate common mode currents (potential RF in the shack, plus a further distortion of pattern).
The above are rules of thumb. Best analysis would be to put your particular antenna geometry into an antenna modeling program (NEC2, MININEC, et.al.)
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$\begingroup$ So if the first counterpoise points East and I add a second one more to S, I'll receive and transmit better through the E and South direction, correct? $\endgroup$– JimCommented Feb 15, 2020 at 15:57
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