Key on cb antenna, full length is best, but that is 102". Bending one to make it shorter makes it less effective than a vertically mounted coil type.
The next best thing is the coil mount in the CENTER of the mast, not the base. This balances the signal on the antenna, unlike bottom mount coils (the majority of you reception is at the bottom of the antenna, not good).
Try to mount the antenna near the center of your vehicle, I put mine in the bed of my truck to protect it and enhance 360 degree reception.
If you put it on a corner you will have the best reception will be in a line through your vehicle (the opposite corner, kind of hard to explain).
Also make sure to mount it vertically.
What I did was get an elcheepo WalMart cb, put a cigarette lighter plug on the end, and a magnet mount center coil mount antenna.
I can pull my cb an not worry about it getting stolen and stick my antenna anywhere.
Hope this helps.