I had the same issue. It turned out to be the nano was not reading the encoder when running ubit files, either factory or the CEC software. It would allow menu selection but not frequency change. The same was true on 3 Nanos.. but they all came from the same place. I replaced the nano with a new one from another source and the problem cleared right up.?
Also, look for John, VK2ETA, or Jim Sheldon. They are both doing some neat stuff regarding a Raduino diagnostic tools.
