Is it the RF901S module? I had issues with this being very slow to bind when there are a lot of transmitters fired up at once - i.e. at the start of a heat or final when there are probably 15-20 turned on...especially bad indoors. If you read up on the KO threads on rctech.net forums (100s of pages) it seems lots of 901s were returned early on for re-calibration or some such, but it seems there has always been the issue with it. I couldn't hack it any more so went for the RF903 FHSS module which thankfully has been faultless so far, binds very quickly whenever, bad times that it means new rxr's too
