Stereo install

I just installed a new headunit in my 1999 mirage de. After I installed it the car wouldn't hold a charge or turn-over. I jumped the car 3 times and it would run for 30 minutes, i would turn it off and it would die again. Now when running the car to try and rejuvenate the battery the a/c kills the car! whats going on here? Any help would be appreciated thanks.

disconnect the stereo to make sure that its the stereo, any amps connected as well? the only thing i can think of is maybe you directly conncted the stereo directly to the battery and its draining it, or your alternator is bad

How do you install the radio antenna. Especially the piece that is in the car frame?