Here is million bucks question. Situation:
Tower A (RB493AH) supplies tower B and C with 22dBi flat panel 5Ghz antenna @ 5180Mhz.
Tower B runs R433AH with 2.4Ghz AP b/g (2427Mhz), 5Ghz AP (5300Mhz), Station WDS -> Tower A.
Tower C runs RB532A with AP 2.4Ghz b/g (2457Mhz) and Station -> Tower A.
When on tower B traffic on 5Ghz AP becomes >7Mbps, tower C and B CCQ goes down rapidly to 10-15% and p-throughput ~100-200kbps. When tower B 5Ghz AP is disabled - CCQ on tower C and B becomes back to 88-100% and p-throughput ~30000Kbps.