Something else that is important is how your antenna is loaded, in regards to where you are placing it.
If you drive a t2000, or 387 pete, some are mounting antennas from the rear of the cab so they can get a good ground. When doing this, you need to be sure you are using a "top loaded" antenna. Otherwise, you are killing yourself in terms of receiving or getting out. Firestik and Wilson both have good top loaded antennas, and you will want a 5 footer if you are mounting from the rear.
Another tip, you need 27 feet of coax to run from the rear of the rig, all the way underneath, and back inside through the firewall. Clay's radio shop in Gordon, TX. actually sells the coax, preassembled especially for these rigs
I haven't been in my 387 very long, so I haven't got my antenna setup just yet, although I am thinking of hanging it from the side of the cab, instead of the rear. (mainly so I don't have to crawl under the truck to tie off the antenna cable.