I am installing one of the new Goodmans DAB units into my 2001 Fabia.
As soon as I plug the aerial in, I get loud static on AM (and very
weak FM). I don't get the same problem with the original factory fit
unit, and the Goodmans works fine with a temporary aerial.

Possible solutions seem to be

(a) the antenna cable has got snagged somewhere en route - can't see
anything, and why would it cause a problem on one head end and not the
other?

(b) the antenna (which is one of those short roof items) is a powered
design, and isn't getting 12v.

How is the power supplied to the antenna? Is this supplied up the
coaxial cable, or is there a separate wire? If so, is this present on
the ISO connector (in which case presumably I can patch across).

If I have to replace the antenna (I've heard this can be helpful for
DAB) how do I get the damn thing off?

Any ideas gratefully received.

Phil