No AM Radio reception on CD70

[DurhamRed]

Hi all,
ever since I've had the car I haven't been able to receive AM radio broadcasts. My CD70 H/U works fine in all other respects. Now this isn't normally a problem but I really could do with hearing 5 live on Saturday as I may be on the road when my football team is playing in the play-offs and the commentary is on 5 live.
As I'm based in the North East and my team isn't I dont have the option of local commentary through an FM broadcast. So any ideas why AM doesn't receive radio broadcasts (it dont work no matter where I'm at in the UK!) and does anyone know how to fix it?
FM broadcasts and sat nav signals are all perfectly ok!
Cheers
Oh and to avoid the questions - its old big head's mighty reds!

[rockh]

Dodgy aerial I would assume as don't think they would fit a ferrite aerial inside the radio.

[Robsey]

I thought this, but didn't answer in case I made myself look a div.

New aerial base is the most likely remedy.

[DurhamRed]

Thanks for the replies - will look into this.

[Exclusive BV]

I had a similar issue on my previous astra. FM was ok, but nothing on AM.

Turns out the aerial was not earthed properly. Try touching the aerial with the radio tuned to 909 or 693, if it bursts into life, there's your problem