Boltek recommend that the antenna should be mounted above any metal structures.
I've got two Boltek antennas (one for the LD-250 and one for the StormTracker) which are mounted within 6' of each other and I haven't had any strange problems.
The best way to mount the antenna is to use PVC pipe and use either nylon screws or cable ties. I would mount it as high as possible without making it a lightning conductor (if it's outside)!