That antenna would probably fit on the bracket you had before, with the 3/8" hole drilled out to fit the UHF connector.
But if you can fabricate enough to weld something on a bracket, I'd get an NMO antenna, and and an NMO mount. An NMO mount just needs a hole about 7/8 or so in diameter (3/4"?) with enough metal around it for the antenna to screw down on it, maybe 1.5" or so - guessing. That's the most common mount for VHF/UHF mobile ham radio, and almost all commercial radios that are VHF high band or higher. Take a look at a police car or most taxis, and they'll have those mounts.
Anyway, with 2m, if you have the NMO electrically well attached to a bracket where there is a more or less straight path of 18" or more in one or more directions, then you should be OK. Ideally it would be in the middle of a flat metal roof, but I think a steel or aluminum cross-member of a roof rack would be fine. And just my 2 cents, but for 2m, assuming you have some kind of a ground on the mount, higher is more important than other considerations for it working well. And past 18" or so isn't going to buy you much, in my opinion. The "dB gain" figures that the manufacturers brag about should be taken with a *huge* grain of salt...as in, don't pay any attention to them at all. Hope this helps and I'm not being to rambly...has been a long day.
But if you can fabricate enough to weld something on a bracket, I'd get an NMO antenna, and and an NMO mount. An NMO mount just needs a hole about 7/8 or so in diameter (3/4"?) with enough metal around it for the antenna to screw down on it, maybe 1.5" or so - guessing. That's the most common mount for VHF/UHF mobile ham radio, and almost all commercial radios that are VHF high band or higher. Take a look at a police car or most taxis, and they'll have those mounts.
Anyway, with 2m, if you have the NMO electrically well attached to a bracket where there is a more or less straight path of 18" or more in one or more directions, then you should be OK. Ideally it would be in the middle of a flat metal roof, but I think a steel or aluminum cross-member of a roof rack would be fine. And just my 2 cents, but for 2m, assuming you have some kind of a ground on the mount, higher is more important than other considerations for it working well. And past 18" or so isn't going to buy you much, in my opinion. The "dB gain" figures that the manufacturers brag about should be taken with a *huge* grain of salt...as in, don't pay any attention to them at all. Hope this helps and I'm not being to rambly...has been a long day.
