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From: David Jefferies
Date: 14 Feb 2002
Time: 05:44:28
Remote Name: 131.227.76.10
You MUST have some kind of counterpoise to your 5/8 monopole. How you achieve this is the question. If you have a fibreglass body shell, it is unlikely that the vehicle will provide a very adequate counterpoise. I suppose the monopole would be 125 cms at lambda 2 metres, so your proposed four radials should each be at least 1 metre long from the base.
I suggest experimentation. Number and length of radials, thickness of wire or rod used to make them. With any luck they don't need to be straight, or even sitting all in the horizontal plane precisely.
I'd hazard a prediction that adding the ground plane radials can do nothing but improve the situation. The car body underneath should have not much effect after the radials are in place.
regards
DJJ