One of my beta testers (2engsout on RCU) is writing up a good instruction sheet on range testing. I will post it in a day or so when he gets done. His procedure is to basicaly baseline your airplane with out twinsync in it and mark the distance with and without engines running. Then repeat the process with the twinsync in and the engines running with the antenna down. The important thing is how much did the range go down due to the twinsync and the RPM sensors being installed. You should not see more than a 10% decrease in range with the engines running. Typically control surface range is not afftected at all it is only throttle fail safe range that is afftected. Have you done a range test with and without the twinsync installed with engines running. I would not expect the TwinSync to have any impact on control surface range (with glow engines). Gasoline engines are a different story to to spark plug noise if not using a metal shielded spark plug cap.