Which antenna gives the most range on the 320 the roof mount or the 42" telescopic antenna

The magnetic from buzzards roost has more range than any i have seen or made,if using a marine radio run it on low.It cost 50 dollars

Magnet antena in center of roof works best for me signal will pick up better.got to be in center.signal will bounce to your antena better.

Will my CB mess with the garmin if I put the magnet mount antenna in the middle of the cab

Adam the CB runs on much higher megahurst but the cb if high enough wattage output can also run a neon light if held close to antenna.reception should not interfear however It might be better to cut off GPS when you key mike. sitting under high power elect lines can interfear. How about cell phone enough static elect. to ignite gas tank when pumping gas.????? cell phone already messed up my brain according to my WIFE. Buddy