w108 Aux Fuse Panel

[Labadie250s]

I have a 1967 250s. I have been using a mono Becker radio that I bought off craigslist for about a year now. I'm putting in a brand new Blaupunkt Stereo fresh from the factory. My plan was to mount it under the dash (don't freak out I wasn't going to replace the Becker, I'm aware how shameful that is). But I wanted to design the new stereo as to not interfere with the 250's already fragile electrical system. I have an aux fuse panel under the hood, I have heard that this was for the radio and power antenna. How do you know which is which? How do you know if you have a power antenna? Has anybody had luck getting decent power for a aftermarket stereo without tapping into the ignition switch? I attached a picture of the fuse panel, how this helps.

250s daily driver