(Noob) VHF repeater minimum working distance

I’ve looked around the net, but couldn’t find any info so here goes.

Is there a minimum distance between my employees with a VX-231V and our 50w repeater?

The repeater is mounted on the roof of one of our 30’ tall buildings with the antennas mounted on 15’ masts.

Our company’s outdoors sits on 80 acres with the repeater in the middle of it.

This only comes up because some of our security guys complain that the repeater doesn’t work right even though I can talk to it 2 blocks away.

The Flea Market Inc.

Any time two radios are ‘too close’, extreme high power can desense the reciever of the listening radio and mess up reception, though this is less common with the more expensive serious commercial gear (which is one reason it’s more expensive).

At first thought, I’d say, you’re covering 80 acres, maybe 1/2 mile range at most, and using the massively exessive power of 50 watts for the repeater? 10 watts would be more reasonable, I’d think.

I inherited the position and I’m slowly learning what I can, and the repeater was already installed when I got here. It’s a DIY Icom F-121S pair setup. I gather that depending on the radiation pattern of the antennas, that it would be less efficient closer and more underneath the repeater are?

There is a possiblilty the handhelds used by the staff have a “talk around” function that bypasses the repeater. If so, this could help issues like that.