Reservations and use outside the US have a non-exclusive legal status • The
Canadian Radio-television and Telecommunications Commission (CRTC) enacted such a ban on Channel 37, but radio astronomy has no exclusive status on this channel. •
Mexico observes a similar ban on the use of this TV channel, but the allocation, like Canada's, is not exclusive. •
Guatemala has a ban on Channel 37. •
The Bahamas has a similar ban to Canada's on Channel 37. •
Belize has an absolute ban on Channel 37. • Most
NTSC System-M countries have an informal ban on Channel 37 as well but give radio astronomy no exclusive use of the channel. The
2016-2021 repack left no US, Canadian, and Mexican OTA TV broadcasters
above UHF 36. Many small-market
rebroadcasters were taken
dark by their corporate owners. This left former UHF 38–83 in the hands of cellular telephone and land-mobile operators, with UHF 14-36 as the main OTA TV broadcast band and UHF 37 as a vacant guardband. Since July 2000, Channel 37 may be used in the US for medical
telemetry equipment on a co-primary basis. The equipment must emit no more than one
watt of
effective radiated power and is for use in hospitals and other such facilities. • The power level permitted by the FCC is many times more than the amount allowed for
Part 15 unlicensed broadcasting. • In US areas set aside for radio-frequency silence, the equipment is banned by statute and regulation. • The seemingly-low power level can be troublesome for radio astronomy equipment, which depends on detecting extraordinarily low
signal strengths. Any use of the same frequencies raises the
noise floor, thereby decreasing the
signal-to-noise ratio and making the work more difficult.
Channel 1 was also removed from the TV
bandplan in the late 1940s,
channels 70 to
83 (800 MHz band) by the 1980s mainly for cellular telephone and trunked two-way land mobile radio systems and, in June 2009, channels 52 to 69 (700 MHz band) for
mobile phones,
emergency services and
mobile TV services such as
Qualcomm's now-defunct
MediaFLO (channel 55). Additional channels from 38 to 51 (600 MHz band) were auctioned in early 2017, leaving channel 37 as a
guard band between repacked TV stations and more mobile networks, for which
T-Mobile US won most of the licenses. Certain channels, 14 through 20, are used for land mobile communications in some large metropolitan areas in the U.S. However, facilities using this decades-old co-allocation are treated as just another station to avoid interference to in their local area. The channels displayed by
cable converter boxes under these numbers are not on the same frequencies as their over-the-air counterparts; there are also
virtual channel numbering schemes in use in
digital television which do not map directly to fixed frequency channel assignments. As such, a "cable 37" channel may (and most often does) exist, but on a much lower frequency. == Outside North America ==