Ive been thinking of doing this on my 4runner, i got the idea from a post here.

a firestik doorjamb mount by the tailgate with a 5' firestik antenna.

the more i think about this the more i uestion it. it doesnt seem like it would have a good ground plane and cause the radio to be directional. im going to be using a modified cobra 29 radio so i want the best antenna i can get for a far from stock radio.

i will be using the radio virtually all the time, not just on the trails so i dont want to settle for some mudduck radio.

 

the best kind of mount would be on the roof. the roof provides a better ground plane and it wouldn't be directional. I just bought a 102" ss whip which people give great reviews on and i got it from radio shack for $25. yeah its huge but its best for performance because there is no loading coil. loading coils cut efficiency. the best kinda mount would be where you drill a hole through the roof and mount it solidly to the truck. me i don't want to drill holes in my roof so im planning to use a HD triple magnet mount. I am also running a modded cobra 29 gtl made in '76.

 

you could poof the roof, and center it for the best omnidirectional pattern, but.... you have to reinforce the mount.

a piece of sheet metal affixed to the underside of the roof where you drill the mount would be a good idea, since a 102" whip, fiberglass antenna, etc... can bend, flex, and put a good deal of stress on the metal.

ground, ground, and ground some more. ground straps from hood, doors, etc... to frame or engine ground. ground radio well.

also keep in mind that large antennas on top of roofs (esp. vans and suvs) are NOT drivethrough or parking garage friendly. expect to hit a lot of trees and sometimes even freeway overpasses.

you could probably do okay with a 102" whip mounted to the center of your rear bumper. would be directional to some degree, but at least the radiation pattern would be approximately straight ahead, instead of off to the front and side if you went with a corner mount.

if you are set on using the firestik, make sure the loading coil is above the roofline.

the best antenna you can afford will not perform up to maximum ability if you don't have it tuned for lowest SWRs as well (particularly so with a modded radio or external amplification). SWR meters are cheap insurance.