I've got a 2', more or less, antenna on my truck that works REAL nice on
all the bands my scanner will pick up.. I think it's an RT7 or RX7,
somethin like that.. Real nice scanner too.. The antenna has a regular
antenna thread just like a hamstick or any other popular mobile antenna..

Radio Shack sells a multi band scanner antenna that you might look at.
May be able to fashion a copy from it if you're sneaky..