I installed a light duty trailer hitch on my E-300 td. Then had machine shop make a mount for me that fits on the hitch, you can get one here..

http://www.texasbugcatcher.com/cata/tbcspec.htm

If you cant get it made up locally

The very large "Bug catcher style" antenna sits off the middle of the bumper and and works great.

One more reason the TD is a great car...no static on the radio!