Check the main radio fuse on the I/P panel located on the side of the dash as soon as you open the drivers door 10A radio fuse. Or go the the battery area underneath the rear seat,look for the right hand fuse juction block, I/P fuse #2. And the third area you should check is the power antenna itself,
attached to it you will find a relay for the power antenna,color grey or black square box.
Hope this helps. let me know.
jb