Channel 1 (NTSC-M)

In North American broadcast television frequencies, channel 1 is a former broadcast (over-the-air) television channel. During the experimental era of TV operation, Channel 1 was moved around the lower VHF spectrum repeatedly, with the entire band displaced upward at one point due to an early 40 MHz allocation for the FM broadcast band.

FM was moved to its current frequencies in 1946. TV Channel 1's last location was 44 MHz to 50 MHz.

Land Mobile Radio and television broadcasters shared the same frequencies until 1948. This shared allocation was eventually found to be unworkable, so the FCC reallocated the Channel 1 frequencies for public safety and land mobile use and assigned TV channels 2-13 exclusively to broadcasters. Aside from the shared frequency issue, this part of the VHF band was (and to a some extent still is) prone to higher levels of radio-frequency interference (RFI) than even VHF 2 (System M).

Neither Canada nor Mexico allocated television frequencies until 1946, so the historical Channel 1 (System M) is exclusively a US allocation artifact.

Channel 1 was allocated at 44–50 MHz between 1937 and 1940. Visual and aural carrier frequencies within the channel fluctuated with changes in overall TV broadcast standards prior to the establishment of permanent standards by the National Television Systems Committee.

In 1940, the FCC reassigned 44–50 MHz to the FM broadcast band. Television's channel 1 frequency range was moved to 50–56 MHz (see table below). Experimental television stations in New York, Chicago, and Los Angeles were affected.

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