Why??? when I test my cobra 75wx st cb using a hand held I talk/ recieve great 100 yards away...but when on the trail I only hear others well but can't transmit.
powering off separate voltage supplied at fuse panel. All pro "Bandi" on rear of vehicle at rear door highest hinge. I can hear all transmissions withing 200 plus yards. Others can only hear me when I'm within a couple of hundred feet.
First, make sure your antenna to coax connector is installed correctly. Make sure any plastic/nylon rings are in place. If the center of the coax is grounding out, you won’t get out. Did you make up the coax for the radio or did you buy it with connectors already installed???
Second, find a way to run a ground strap from the mount to a good FRAME ground. Make sure when you install this ground to scrape/file/grind off any paint where it attaches.
Third, find someone with a good SWR meter or antenna analyzer to adjust your antenna. Maybe a fellow FJC owner or Cruiser club member may have one. Antennas are like TV’s, they all look great, but each one needs to be tuned to the needs of the place where it is being used in.
THis sounds (and certainly is) a bad antenna problem, likely in the ground. If your antenna requires a ground plane to work, you don't have one. You could scrape paint and ground the antenna to the body, but it's a new vehicle, so I'd be hesitant to do that. Also, you need to use grounding braid, not wire to make your grounds.
I would run a mag mount instead. Then you can at least check and see that your radio works as it should. If you can only hear a couple of hundred yards, and transmit a few hundred feet, you would be better off shouting!
Assuming your antenna is not set up right, I would not use the radio since you will quickly fry the output transistors.
Anyway, a mag mount borrowed from a friend will at least proof your radio, and then you can work on the stuff needed to optimize your antenna.
As crappy as CB radio is, several miles line of sight should be doable without anything fancy.
John, this may not have a bearing on the outcome of your installation, but the 75 wx st doesn’t have a “mic gain”, at least not external. All that is on the 75 wx st is a speaker volume control (gain) and a squelch control. At least the one I have doesn't have one. A mic gain controls the strength of your voice level going to the radio, too much mic gain and your voice will be garbled/distorted on the other guys receiver.
As Cruiserdrew points out, try a totally different antenna which is independent of the current one and see how that works. Then go back to correct what you now have.
It's almost always an antenna installation problem. Borrow someone's mag mount to see if things are ok with your radio. If so, then follow the antenna mount manufacturer's installation instructions. Pay particularly close attention to the little rubber insulator that is suppose to be in there and how it is used.