So after many different attempts to fix the weak radio reception in the 159 I decided to get a little drastic with it
The 159 aerial is active and requires phantom power so if you replace the factory head unit with an after market one you need an in-line power adapter to deliver power to the factory aerial. This is fine until your modern head-uint has DAB radio or GPS as to get these working you now need to stick all sorts of window and dash mounted additional aerials on the car that just look tatty.
So first tried an in-line FM/DAB splitter but unfortunately despite what any of these are advertised as they are only compatible with passive aerials and this means they will not work in the 159 at all.
So after a number of different window mounted ones that all ruined the look of the car I decided that the only solution was to replace the factory aerial with an after-market unit that was capable of delivering the features I needed without spoiling the lines of the car.
A little research found this: Kinetic DRA-6005 GPS FM-AM DAB car aerial
This unit gives FM/AM/DAB/GPS all from a single unit and is not a huge difference in size than the OE one.
It took about 3 hours to fit it and its not a massive job but you do have to get the roof lining loose at the rear which takes a bit of effort.
The short process is:
1) Remove the 2 press studs in the rear rear of the roof lining
2) remove the rear light cluster & remove the nut behind it
3) remove the airbag logos off the two rear quarter panels and remove the bolts behind them
4) remove the top bolt from the rear seat side panels (assuming you are split fold) and slide forward to access the remaining bolts under the the rear quarter panels. then pull inwords and remove both
5) remove the rear grab handles
6) pullthe door trim away from the roof area.
7) the roof can now be pulled down to access the aerial
8) remove the aerial nut (22mm) and disconnect the FAKRA connector
9) pull the aerial hard out the roof (it has a couple of small tabs that will bend out the way
Now just install your new aerial and put it all back together in reverse! dont forget you run all your new cables to the front. I bought 3 x 5 meter extension cables from the FM/AM & DAB & GPS to make life easier.
Total cost £100
I now have perfect reception and GPS preparation for an upgrade planned soon.
I am sure a few of the purists will recoil in the horror of me changing an external feature of such a pretty car but I am sorry to say, function in this case outweighs form.