aerials mounted on fibreglass cars

[Astacus]

I am an electronics know-nothing but I would like to fit a roof aerial to my TVR Vixen rebuild. Can anyone advise on practicalities? I am pretty sure it had one once, but the hole is filled in. Do I need some sort of metal plate under it?

Thanks

[eccles]

Are you thinking of the metal plate as reinforcement of the roof or as some sort of earth?

My old kit car had a standard radio aerial fitted with no extra wiring and had no reception issues. It didn't need a reinforcing plate as the shell was quite thick.

[Astacus]

I think the plate is some sort of ground plane for the antenna, but reading around it’s not clear that receivers need one. It may be limited to transmitter receivers. As I said I am a complete novice as far as this goes.

[Rough101]

The metal plate is just for reinforcement. The earth can come down the coax from the head unit to complete the screening, no need for a local earth.

[dxg]

You do need a ground plane though. Otherwise the standing wave won't happen.