Mobile Unit Antenna far from base question

I have a Vertex Standard Mobile UHF radio that is on a desk in someone’s office here at the plant that I work at. It is set on low power (15 watts) and it can’t get out into the plant past this really big concrete wall.

My idea was to run a cable to an antenna mounted on the other side of the wall. So, it could get out in to the plant.

It looks like I need LMR-400 cable. But, are there other things that I should consider? Is there a max distance that I can run this antenna cable?

It’s probably at least a 100 foot run, maybe 200 feet. Is that going to work?

200ft is a serious run for UHF. To be honest, this is where repeaters up high work the best - everyone has a path to them, and they are up in the clear. your cable idea might work, you will lose roughly 50% of the signal on receive and transmit at 450MHz. If this is acceptable, it can be done.

We did a more accurate measurement of the wire distance. It will be between 65 to 75 feet.

Is that more manageable? Or would you still consider using a repeater?

I was also thinking of programming the radio to 25 watts, rather than the current 15 watts.

the cable length of course impacts on reception too - so increasing the output power would mean reception would still suffer, but to be fair, the cable length isn’t a crazy length or loss. the biggest problem is that if you’ve discovered a problem with getting through that wall, it suggests that signal strength all over will be exactly the same - very variable. If you remote the antenna, then there will still be paths that are poor. A repeater is expensive of course, but in a high central point can reduce the path lengths and dead spots. if the vertex is in the only bad reception spot, then the remote antenna should cure it - the only real thing to consider is if it will do the job. Can you not go through the wall, rather than a long distance out and back?