From: Richard Griffin <rgriffin@iee.org>
Cc: Club GTI Mailing List <clubgti@egroups.com>


You could do this fairly easily with a de-coupling capacitor and your
existing heated rear-window element.
You'll need to get yourself a length of 75 ohm coaxial cable from an
electrical store, long enough to run from the car radio to the rear window
(you obviously need the appropriate plug for the radio end of the cable, as
well).  The capacitor you'll need will be a 47uF (micro-farad)
non-polarized one, rated at 12volts minimum, again from the electrical store.

Connect the plug to one end of the cable (centre core of the cable to
centre pin of the plug & braided outer section of the cable to the outer of
the plug).  You may need a soldering iron for this - depending on the plug.

At the heated window end, connect the braided section of the coaxial cable
to the earthed bodywork somewhere (ensure a good connection) and the centre
core of the cable to one of the legs on the capacitor. The other leg on the
capacitor must be connected to the heated window live connection which is
usually found on one side of the glass.  (Test using a volt-meter)

Plug everything in and Bob's your uncle - one hidden car aerial!

WARNING!!!!  If you DON'T use the capacitor, when you switch on your heated
rear window you will connect 12 volts to the aerial socket of your car
radio, which could be ......ahem........ "unfortunate" !

The only other problem could be interference from the alternator in the
form of a whining noise over the radio station, which will need to be
corrected using a standard suppressor from your local automotive store.  I
don't know if this will be necessary since I've never tried it.  ;-)
    
STANDARD DISCLAIMER:  Try this at your own risk - if your 2000ukp car radio
goes up in smoke, then don't blame me etc etc.
    
I knew that the electronics degree would be useful for something..........
    
Hope this helps,

Richard