W123 Constant 12v & ACC 12v Location Options

[danderso]

Hello,

I'm trying to install a security device in my W123 that requires a Constant 12v, ACC 12v, and a Ground.

It needs to be in the interior of the car, as it isn't waterproof.

It needs to be concealed, but also not overly buried in metal so a signal can be reached!

Anything come to mind? Does the power antenna have these?

Thanks !