The broadcast television frequency band isn't as broad as it used to be since the transition to digital TV. With digital TV there are fewer RF channels but more virtual channels on TV.
Background
RF stands for radio frequency. The broadcast television frequency band is divvied up into RF channels. Each RF channel spans a range of six megahertz. For instance, RF channel 11 is assigned to the 204 to 210 megahertz range.
Features
With both digital and analog TV, there are two television bands on the broadcast frequency spectrum: the VHF (very high frequency) band and UHF (ultra high frequency) band. VHF radio frequency channels run from 2 to 13, occupying most of the 54 to 216 megahertz range. During analog TV broadcasting, UHF radio frequency channels ran from 14 to 69, occupying the 470 to 806 megahertz range.
Difference
Now that the transition to digital TV is complete, the UHF television band has been reduced. The UHF band now runs from channels 14 to 51 (470 to 698 megahertz). The 52 to 69 RF channels have been reassigned for other broadcast uses.
Effects
Since digital TV signals are more "economical" than analog TV signals, digital signals are able to carry more information while taking up less space as compared to analog signals. With DTV, television broadcasters have the ability to offer more features and more programming (more virtual channels) on their assigned radio frequency channel.
Misconceptions
A television broadcast station's "radio frequency channel" is not the same thing as the "virtual channel" you tune into on your television set when you watch TV. With DTV, a TV station could be assigned to RF channel 19, for instance, but you might know it as channels 2-1 and 2-2 on your television set.
Tags: radio frequency, frequency band, megahertz range, analog signals, broadcast television