A good coaxial cable will have a flat bandwidth of say, .5 to 900 MHZ. TV transmissions have a bandwidth of 6MHZ (Sytem I) and are transmitted in the upper half of the band from from about 421 MHZ upwards. So the lowest channel is on 421 MHZ, the next one on 427 MHZ, then 433 MHZ. Because of deficiencies in the receivers, then local channels are not next to each other. But are spread, CH1 = X MHZ, CH2 = X + 12MHZ, CH3 = X +24 MHZ....
The modulation for the vision carrier is vestigial sideband transmission, AM with one side band filtered off. The sound carrier is normally sat at Fv + 6MHZ and is FM.
Frank