Power Antenna

[BBcallaway]

I am having an issue with my radio / power antenna. With the car on acc. The antenna works perfectly,but when the car is running it does not works at all. If the power is disconnected at the radio for the antenna then the radio works fine,but the antenna does not work. Any ideas anyone?
Thanks

It is an older alpine stereo.

 

[davelostmissing]

Based on my interpretation of above: bad RF connection somewhere radio>mast, engine electrical noise swamps the radio "front end" when running. Then antenna's motor shuts off at the extremes (up/down)?