My symphony radio, in an '03 Octy TDI Elegance, developed poor reception, especially AM (see related threads) - all original kit. In searching here I found that the base of the aerial is prone to corrosion damage due to water ingress (other possibilities are loss of power to radio pre-amp in the aerial base). I did not find any info about how to get at this bit of the car and Haynes say little other than that you need to remove the soft inner boards and plastic to get at it, which they helpfully suggest requires an expert.

Undaunted, I went ahead. The first bit of plastic (along the edge by the hatch back) pulls off easily. Then the rear passenger grab handles come off (posidrive screws behind plastic covers which flip up when you unclip them). The wee lights are slid out, but not taken off. Then the side pieces of plastic can be carefully pulled away (these cover the back sides of the interior cabin near the hatch), noting that they slip out from rubber seals (rands). This done, the sponge coated interior roof board can be carefully pulled down from the back. Don't pull down too far as the board can crease and this is not good at all - about 4 inches is plenty.

Now you can feel and see a fairly large nut in the roof with the aerial wire coming out of the bottom. This wire has a connector concealed in a piece of sponge a few inches back from the nut, so you can remove the whole antenna if needed. I unscrewed the nut, loosening it first with an 8 inch adjustable spanner (so I don't know what size the nut is). Once off (all in one piece with the special washer), the aerial, with its base, pops up through a small square hole in the roof. Turning the aerial base over, two small posidrive screws are found holding it together. As well as this there is a plastic skirt on which it stands and this can be prized off to reveal a rubber ring seal. I unfastened the little screws to open the base, revealing the amplifier and the way it connects to the antenna.

With this lot exposed, I switched on the car and radio and put a voltmeter on the antenna terminals of the little amp. I got 10.4V DC there - good news.

I noticed some slight corrosion, so cleaned it all up with meths and a cloth, then with fine metal abrasive paper, I cleaned up the terminal contacts and finished off with a spray of WD40. I put grease on all the seals and fastened the base back together. To re-install the aerial base is best done with a helper who holds the aerial base down as you put the big nut on from below (you can't reach to both on your own). All the time this was going on, I was listening to the radio on AM and it intermittently jumped from nothing but crackle to passable reception. Thankfully, on tightening the nut and checking all was correctly aligned and secure, the reception remained usable. All that is then needed is carefully reversing the procedure on the internal cosmetics.

Hope this helps others.

Thanks for that; very helpful.

My aerial is perished/damaged where it unscrews to fold flat. I have read that it is difficult to replace just the aerial itself & that the whole unit must be done. I didn't really want to get into removing the headlining but your post has given me a little more confidence about doing it.

Thanks

I did mine, but it was a lot more simple than that as it's an estate model. I removed the piece of trim and slid my hand under the roof lining. There must have been a bad connection on the antenna which I disturbed. It's been fine ever since though.......

So this sounds like its common then. Are there any other joins in the aeriel cable that anyone knows of?

I have an estate with an intermittent reception loss problem. I thought I had managed to prove it by slamming the boot and getting it to work/not work but not every time.

Might have to check this out, cheers