I reworked 5 baseball scoreboard controllers with ES devices. jp is right: build the squelch, it makes All the Difference. Follow Lynxs' layout rules too.
These units are solid to ~200' and workable to >500'. This was a redesign, previous used the LC series: being A.M. & ~400MHz, interference was problematic.
They run: 9.6k baud, 8/N/1, data block={sync(5), unit address(1), keycode(1), BCC(1)} BCC is (addr+key) inverted, sync is a $55 ("U"). Good Hunting... <<<)))