Radio Reception poor with aftermarket antenna

[Zoro]

Back when I first got my XJ Zoro the stock radio was busted so I removed it and I had a nice power antenna(one of those AM/FM/CB deals) laying arround so I installed that after removing the stock antenna setup.

I got a new radio a month later and the reception sucked(and still does) when the radio is all the way in the dash and all the way screwed in but for some reason I get perfect reception with the whole radio sticking out of the dash and my had in front of it. I can only pick up stations while the motor is running if I'm close and the signal is strong or if with the motor off if they're a little bit farther away.

I was thinking that it could be picking up vibrations from the motor because the antenna wire going into the radio is straight instead of 90* like the stock one is but that wouldn't explain about the shotty reception with the motor off also.

There is also about 15ft of the coax cable looped and tied up under the dash as it was extra, could this be the culprit? This is a large power antenna meant for AM/FM/CB but I didn't have the CB adapter so the CB option isn't hooked up. I tried to follow the stock wiring route the best that I could but in the end I ended up bypassing something big up under the passenger side of the dash, could that be the reason? I grounded the antenna to the passenger side door hinge with a larger grade wire...Any other ideas? This is a 90 XJ Pioneer 2-door.

Sorry for the long post, just did a 500 mile road trip and it was driving me crazy.

[old_man]

What you are describing is a bad ground where the antenna mounts to the fender.

[Zoro]

Old_Man-How could that be fixed?

Thanx

[bigwhitey]

The plug for the back of the radio is probaly grounding out with the radio pushed all the way in causing you to loose reception.
Also anytime you have 15 ft of any extra wire or cable looped up with you radio it's going to suck.

try to find an antenna with a shorter cord and a 90 degree bend on the plug.