I have a 2014 VW Polo with a factory fitted AM/FM/DAB radio.
A few months back the DAB radio became less sensitive.
There doesn't seem to be anything I can find on the Internet about this so for anyone who has a similar problem, this is what I found out.
Firstly, there are two types of aerials on VW Polo cars of about that age. One has a flatter looking base, mine is the (earlier I think) more prominent base.
The base of my type is packed with electronics (something I suspected but only found out when I had the old one to take apart).
I bought a replacement (new from VW - it wasn't cheap!) and had it fitted.
This fixed the problem and restored the DAB reception.
If getting at the aerial base inside the car hadn't been so hard (a significant proportion of the overall cost was getting someone suitably skilled to take the car apart and fit the new aerial) I might have investigated the problem more.
The base seems to have two parts (possibly allowing for a DAB and non DAB version of the car) and two incoming co-ax leads, one with a black end and the other with a white connector on the end.
Each has a small connector in.
I did (and still do) wonder if the problem was either a seating problem in one connector (assuming one does the DAB, the other AM/FM) or (less likely) an earthing issue for the whole base. It has a nut with a pearcing collet as part of the fixings and that seems to need to go through the paint.
For a long time (and seperately) I had some electrical noise on weak AM signal reception which on first impressions, this new base also seems to have improved.
All in all and thus far, this seems to be fixed.
As a "garage fix", buying the new base and having it fitted was defititely the best bet. As a DIY job, some further investigation is probably merited before getting the replacement base.
For reference, the base seems to be part number 6R0 031 501 A, the nut 1J0 035 437 & the actual antenna 6R0 035 849 A.
