Weird radio interference

The car is a 1996 Passat TDi - i.e. a deisel.
The radio interference is a clicking noise, present in weak FM areas, which is solely dependant on road speed. It speeds up as I go faster.
It continues even if I switch the engine off
The only electric device I can find related to the transmission is the sender for the speedometer. I tried disconnecting this and it made no difference.
I am stumped.
Any ideas?
--
Chris Melluish



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I doubt that would produce a click - more a whine. Other things that actually *produce* a signal proportional to road speed could be the ABS sensors. Other possibility some form of static discharge - that is likely to give a click rather than whine.
--
*Virtual reality is its own reward*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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London SW

I don't have ABS.
-- Chris Melluish
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Try running a good earth between the metal body of the radio and the car body- you'd be surprised how much that can help.
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