Digital channel election

A digital channel election was the process by which television stations in the United States chose which physical radio-frequency TV channel they would permanently use after the analog shutdown in 2009. The process was managed and mandated by the Federal Communications Commission for all full-power TV stations. Low-powered television (LPTV) stations are going through a somewhat different process, and are also allowed to flash-cut to digital.

Stations could choose to keep their initial digital TV channel allocation, do a flash-cut to their former analog TV channel, or attempt to select another channel, often an analog channel or pre-transition digital channel from another station that had been orphaned. Stations on channels 52 to 69 did not have the first option, as the FCC and then the U.S. Congress revoked them from the bandplan.

Many stations have chosen to keep their new channels permanently, after being forced to buy all new transmitters and television antennas. In some cases where the station's current analog tower could not handle the stress of the new digital antenna's weight and wind load, station owners had to construct entirely new broadcast towers in order to comply with the FCC's DTV mandate.

Most broadcasters were bitter at having to purchase digital equipment and broadcast a digital signal when very few homeowners had digital television sets. The FCC allowed broadcasters the opportunity to petition the Federal Communications Commission (FCC) for special temporary authority (STA) to operate their digital facilities at low power, thereby allowing broadcasters additional time in which to purchase their full-power digital facilities. However, the FCC gave a stern July 2006 deadline for all full-power television stations to at least replicate 80% of their current analog coverage area, or run the risk of losing protection from encroachment by other stations.

Most stations made an election in the first round, and most of those received their requested channels. Applicant conflicts with neighboring stations had to request a different channel in the second round. The third and final round occurred in May 2006.

Some stations requested that the FCC assign the best available channel.

Aside from the practical considerations above, there are also technical considerations which are based on the physics of the radio spectrum. These affect the radio propagation of DTV just as with other signals.

The low VHF channels from 2 to 6, while requiring the lowest power (up to 100 kW analog video or 20 kW digital), are prone to electromagnetic interference. The ATSC digital TV system has severe problems with susceptibility to impulse noise, bursts of interference which briefly render the entire channel unusable, due to its inability to instantaneously determine where in a video frame to resume display when the signal returns. The result is macroblocking and pixelation of the entire signal whenever impulse noise sources (such as motors, appliances or electrical storms) are active. They also are the lowest in frequency and therefore the longest in wavelength, requiring the largest antennas both to transmit and receive. They are also prone to atmospheric ducting, especially at night when the ground (and the air near it) cools rapidly. Because of the antenna size (a properly-sized VHF TV 2 dipole spans approximately eight feet (2.4 meters)) and the fact that there are only five channels in this band, most set-top antennas are designed to receive the higher TV bands.