Question re: power antenna and aftermarket stereo Options

[pandito]

Hey y'all.

A while back, I had come upon a post from a user that was able to wire his stereo in such a way that he power antenna goes up only when the radio is active on his aftermarket unit. For the life of me, I can't find it and I'm trying to get mine to do the same.

Basically, if the HU is on, the antenna goes up. It doesn't matter if I'm using the AUX or the iPod input - the antenna is getting the signal that the HU / "radio" is active and therefore goes up. I want to emulate his deal where it goes up ONLY when the radio is active.

Any help would be really awesome.

[pandito]

Thanks for the ideas / replies y'all! After going over the electrical schematics, I found that the Alpine HUs are all the same in that when power is active to the HU, it closes the circuit for the power antenna, regardless of input, and therefore raises it. Sony HUs can differentiate between sources and can open the circuit when not using the radio, thereby retracting the antenna. I kind of fancy the power antenna so I'll probably not swap it out for a stubby just yet.