I used to take a piece of styrene and wrap the antenna around it being careful not to cross the antenna over itself. I have used tape to secure the antenna to the styrene. Size and shape the styrene to fit where you want it and mount it to the cab floor where ever you want. For the distance I've run or seen most run their trucks you shouldn't have a problem. I would usually find an empty parking lot, tennis court, some large area to see how far I could get away before you loose control, just disconnect the motor and have someone stand there and tell you when your steering stops working as you walk away from the truck and that would be the distance you don't want to go too.
