What's your line of sight situation and how high would the antennas be mounted? Also are you looking to serve clients off the radios while backhauling or is this just to provide a point to point backhaul? ... View more

From a pure RSSI standpoint, those signals are right in the sweet spot for most designs. I'd hazard a guess that signal strength isn't the main culprit with the reported issues.   If this was a greenfield design at 30 feet, I'd lean towards a patch or maybe a downtilt Omni depending on the building layout. You really should do an AP on a stick survey though to validate the antenna choice.  ... View more