mtr2000 ht1250 repeater

Hey, I a bit new to this but I am trying to find out if this can be done. My volley currently runs one mtr2000 repeater running at 100w. No bells and whistles. Just a regular old duplex UHF repeater. the issue we are having is that our portables (ht1250s) do not always hit the repeater. Is it...