According to the data sheet for the nRF51822 the channel range is from 2.400 - 2.483 GHz.
In the radio test example however, it limits the range of test channels to 2.400 - 2.480 GHz.
Is there a reason that the top 3 channels are not accessible? Are they reserved for some other function?
The specification determines what the radio of the nRF51 chip is capable of. I am not certain why they have chosen 2.400 - 2.480 GHz in the example, but this is the range of the Bluetooth Low Energy…