Nothing is 'up', Bart. You have the latest v1.02 firmware fitted. The notes for the firmware explains that the upper sidetone limit is 650Hz. 73 de David G4DMP In a recent message, pa3gyu <pa3gyu at amsat.org> writes >Manual says STP can be varied from 500 to 700 Hz. Mine will not go >higher than 650 Hz. What's up?