I have three different Scanner receivers that do just that, scan the band. Called search mode. They can even program freqs that are occupied, into a memory. I also have an old Radioshack 242 2M FM transciever that can be set up for a few different scanning schemes ! I never understood how you can scan to lock on a SSB or CW signal, after stopping there is no steady carrier to keep the rcvr from resuming scan between voice peaks or during a pause between words on CW ??