You need to have the antennae tuned with an SRW meter.Find a CB shop and ask them to tune it.They can give you tips on better performance.Could be the signal is getting cut off because it's below the top of the cab (mounted to bed).You may need to mount it to cab.
I have a firestik II antenna with it mounted to the bed of my pickup with half of a mirror mount. I tuned it once i first got it, but i had to take my antennas off once to put it in a garage, do i need to tune it again? the second thing is that i can be 5-6 miles away from our local grain elevator and hear them talking, but when im out coyote huntin with my friend, i cant hear him from 1.5 miles away. I thought about a grounding issue but then i wouldnt be able to hear anyone, or talk to them either. My cable is fine, and my squelch is right above the interference noise. my volume is fine too. we can talk when we are right next to each other though. This is weird because when i first got it, i couldnt hear people right beside me but farther away. Any suggestions? Is it my friends CB instead? I need help.
Note: My CB is also connected straight to the battery for power, but there is less interference when i shut off the engine. The cb is grounded to metal underneath my dash.