Another historical note, within a locality it was almost always the case that only every other broadcast channel was used, e.g. 2-4-6-8... or 3-5-7-9... to reduce interference from adjacent channels.

That's why old VCRs, DVD players, home computers, and other devices that used an RF modulator to connect to a TV display could typically be set to transmit on channel 3 or channel 4, because one of those was almost always unused in a given area.