Electric aerial and radio to ignition

Hi all I'm just about to fit an electric aerial to my car but I was wondering if anyone knows how to connect it straight to my ignition, along with my stereo, I have to manually turn it off everytime I get out the car and it's starting to become a bit of a pain, any help would be greatly appreciated, 

It's a 1981 GL with an early ceramic fusebox, I've noticed that my stereo head unit is cutting out under high volume so I don't think it would be a good idea to connnect my electric aerial straight to the head unit, correct me if I'm wrong guys I appriciate your help as always 😎

Hi. I have a 1983 Golf GL with a Beru electric aerial fitted.

Typically an electric aerial has 3 wires. Two of which are not connected direct to your radio.
 
One is red and is permanently connected to a permanent positive feed to your battery. The other is black or brown which is directly connected to earth, car body or negative battery terminal.

The third wire is blue or green. This is the only lead to connect to your radio. This is assuming you radio had a similar output blue lead to connect it to.

The aerial is driven up or down using the battery power of the red lead and earth. The blue or green lead receives a low powered signal from your radio which operates a relay within the aerial. Your aerial will not create an excessive load on your radio.

It is normal to have two 12V supplies to a radio. One permanent 12V and one 12V ignition controlled. This allows you to turn the radio on / aerial raised and off / aerial lowered when your ignition is off. Alternately this allows you to turn the radio on / aerial raised with ignition On and radio off / aerial lowered when your ignition is turned off.

I would be interested in knowing what your radio model is to see its inputs and output connections. Regards