We have always put up with poor radio reception in the car. Bought a
new car radio to replace the JVC unit that came with the car but the
problem persists.

Looking at this NG saw a 12v booster cable has to join up somewhere -
how can I check out if that is working as it should?

Also would getting a better aerial than the usual VW stubby one that
screws into the roof be of any use?

Thanks