A storefront fortune teller could have imbued TV channels with as much meaning as associations of engineers and the federal government. While radio stations advertise their actual frequency, TV stations proclaim an arbitrary channel number. The government allocated FM radio stations “channels,” but broadcasters opted not to identify with them.
In 1948, the government rescinded channel 1 from TV for use by emergency responders. Even before that, channel 1 wandered before settling down to 44-50 megahertz.
Then there is the curious gap between channels 6 and 7. Channel 6 is 82-88 MHz, while channel 7 is 174-180 MHz. The government snuck the FM broadcast band into that gap among other things. The VHF TV band ends at 210-216 MHz with a large space until the UHF band begins at 470-476 MHz. Initially, the UHF band rose all the way to channel 83 at 884-890 MHz. Channels 70-83 were eliminated in 1982 before being populated with stations. With the coming of digital TV in 2009, channels 52-69 also vanished. (Local channel 55 actually is 44.) Finally, in deference to radio astronomers who were enjoying far better programming than ABC, CBS and NBC, channel 37 was removed from broadcasting. Channels 52-83 currently provide a good portion of your cellphone signal.
In the early days of TV, the major networks attempted to carve out channel identities. Depending on FCC allocations for a given market, CBS, or its affiliates, grabbed the lowest channels, usually 2 and 3, NBC staked out 4 and 5 and the new ABC network aimed for 6 and 7. PBS (then simply known as educational broadcasting) was left with the highest VHF channels in major markets and UHF if they were late to the party. WILL-TV, channel 12, was very lucky to score a VHF channel in our small market. Whether by coincidence or design, for many years, East Central Illinois maintained that network pattern to an extent, with CBS on channel 3, NBC on channel 15 and ABC on channel 17, which simply were 5 and 7 plus 10. However, a few years back, channels 15 and 17 swapped networks.
During the conversion to digital TV, the government gave a second channel to broadcasters for digital during the transition phase. Other than avoiding interference between channels, it was a rather helter-skelter approach. Now the government wants those channels back since they are widely scattered between channels 14-52, squatting on valuable broadcast spectrum. They want to bunch broadcasters on the lowest channels.
This affects you in two ways. First, while analog and digital signals use the same antenna, the frequency (channel) of the broadcast signal determines its optimal design. You may think you’re viewing channel 15, but you’re actually receiving channel 41.
The only area station that broadcasts on its original, actual channel is channel 17. To confuse matters further, channel 12 transmits on channel 9, meaning that it is the only VHF station in the East Central Illinois market. That requires a much larger antenna (as far as the length of the elements) than UHF stations. If you paid an antenna specialist to build an antenna with elements optimized for each local channel, you’d be complaining today.
Over the next couple of years, many stations will change their real channels (as opposed to the channel number you see on your TV screen). That causes reception changes.
Furthermore, when you bought your TV, you or the installer ran a set-up program to scan all available channels, identify their “virtual” channel and commit them to memory. As already has happened here, once a station changes its real channel, your TV tuner no longer sees it. Thus, you should go to the menu and tell your TV to rescan channels every few months, or when a station disappears. Those of you using only cable or satellite need not worry about this. No country could have arranged this more confusingly than America.