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One important reason is safety. One wants the exposed metal part of the coax connector to be at the same potential as the Transmitter case at one end, and any grounded equipment at the other end. Not at a high (RF or A/C) voltage.


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The coax shield must be at ground potential if you want the coax to function as a non-radiating transmission line. If the shield isn't at ground potential, then there will be a non-zero electromagnetic field between the coax and its surroundings. Meaning, it will radiate. The shield could be left floating, but the shield can be grounded without changing the ...


1

A part of the antenna system (system = antenna + transmission line) that is truly grounded can't radiate. Most antenna systems are more efficient when the antenna, the part that is designed to radiate, is up high. So the antenna is deliberately ungrounded. Antennas are usually designed with the assumption that the transmission line doesn't radiate much; ...


1

Lightning takes the path of least resistance I believe. If you have a larger conductor just above the highest point of your antenna going to ground that is a better conductor than your antenna I would think that would cover you.


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