I have a new to me 1990 W124 300D.

It has an aftermarket Alpine head unit and the antenna goes up whenever the head unit is powered up.

I want to minimize wear and tear on the antenna assembly and would like to wire it to be manually switched to go up only when needed.

On cars like this without an antenna switch on the dash, is it as simple as the head unit supplying 12v to the antenna lead and the antenna goes up? If so would it be possible to then just put an on/off switch in the antenna turn on lead circuit?

Would it be possible to retrofit an OEM antenna dash switch and configure it be an on/off switch for the antenna system? Iirc on my previous W123 that had this switch the antenna would still go up but the switch let you raise it higher or lower only?