Channel 37 is an intentionally unused
ultra-high frequency (UHF) television broadcasting channel by countries in most of ITU region 2 such as the United States, Canada, Mexico and Brazil. The frequency range allocated to this channel is important for
radio astronomy
Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
, so all broadcasting is prohibited within a window of frequencies centered typically on . Similar reservations exist in portions of the Eurasian and Asian regions, although the channel numbering varies.
History
Channel 37 in
System M and N countries occupied a
band of
UHF
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
frequencies from . This band is particularly important to
radio astronomy
Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
because it allows observation in a region of the spectrum in between the dedicated frequency allocations near 410 MHz and 1.4 GHz. The area reserved or unused differs from nation to nation and region to region (as for example the EU and British Isles have slightly different reserved frequency areas).
One radio astronomy application in this band is for
very-long-baseline interferometry
Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...
.
When UHF channels were being allocated in the United States in 1952, channel 37 was assigned to 18 communities across the country. One of them,
Valdosta, Georgia
Valdosta is a city in and the county seat of Lowndes County, Georgia, Lowndes County in the U.S. state of Georgia (U.S. state), Georgia. As the principal city of the Valdosta Metropolitan Statistical Area, Valdosta metropolitan statistical area, ...
, featured the only
construction permit
Planning permission or building permit refers to the approval needed for construction or expansion (including significant renovation), and sometimes for demolition, in some jurisdictions.
House building permits, for example, are subject to bu ...
ever issued for channel 37: WGOV-TV, owned by Eurith Dickenson "Dee" Rivers Jr., son of the
former governor of Georgia (hence the call letters). Rivers received the CP on February 26, 1953, but WGOV-TV never made it to the air; on October 28, 1955, they requested an allocation on channel 8, but the petition was denied.
In 1963, the
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...
(FCC) adopted a 10-year moratorium on any allocation of stations to Channel 37. A new ban on such stations took effect at the beginning of 1974, and was made permanent by a number of later FCC actions. As a result of this, and similar actions by the
Canadian Radio-television and Telecommunications Commission
The Canadian Radio-television and Telecommunications Commission (CRTC; ) is a public organization in Canada tasked with the mandate as a regulatory agency tribunal for various electronic communications, covering broadcasting and telecommunic ...
, Channel 37 has never been used by any
over-the-air television station
A television station is a set of equipment managed by a business, organisation or other entity such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth's s ...
in Canada or the United States.
The
2016-2021 repack left no North American stations above UHF 36.
The low-power
WNWT-LD in
New York was given
virtual channel
In most telecommunications organizations, a virtual channel is a method of remapping the ''program number'' as used in H.222 Program Association Tables and Program Mapping Tables to a channel number that can be entered as digits on a receiver's ...
37 in August 2019, thus becoming the first American station to be so assigned via the digital television
PSIP
The Program and System Information Protocol (PSIP) is the MPEG (Moving Picture Experts Group, a video and audio industry group) and privately defined program-specific information originally defined by General Instrument for the DigiCipher 2 system ...
standard. While the channel is displayed as "37.1" or "37-1" on a digital television set, WNWT-LD's physical signal remains on
VHF channel 3, causing no interference.
Allocation issues
Reservations and use outside the US have a non-exclusive legal status
* The
Canadian Radio-television and Telecommunications Commission
The Canadian Radio-television and Telecommunications Commission (CRTC; ) is a public organization in Canada tasked with the mandate as a regulatory agency tribunal for various electronic communications, covering broadcasting and telecommunic ...
(CRTC) enacted such a ban on Channel 37, but radio astronomy has no exclusive status on this channel.
*
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
observes a similar ban on the use of this TV channel, but the allocation, like Canada's, is not exclusive.
*
Guatemala
Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...
has a ban on Channel 37.
*
The Bahamas
The Bahamas, officially the Commonwealth of The Bahamas, is an Archipelagic state, archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of ...
has a similar ban to Canada's on Channel 37.
*
Belize
Belize is a country on the north-eastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a maritime boundary with Honduras to the southeast. P ...
has an absolute ban on Channel 37.
* Most
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170.
In 1953, a second ...
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
Darkness is the condition resulting from a lack of illumination, or an absence of visible light.
Human vision is unable to distinguish colors in conditions of very low luminance because the hue-sensitive photoreceptor cells on the retina are ...
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
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...
equipment on a co-primary basis. The equipment must emit no more than one
watt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...
of
effective radiated power
Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power, such as that emitted by a radio transmitter. It is the total power in watts that would ha ...
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 strength
In telecommunications, particularly in radio frequency engineering, signal strength is the transmitter power output as received by a reference antenna at a distance from the transmitting antenna. High-powered transmissions, such as those used i ...
s. Any use of the same frequencies raises the
noise floor
In signal theory, the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored.
In radio com ...
, thereby decreasing the
signal-to-noise ratio
Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in deci ...
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 phone
A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This rad ...
s,
emergency service
Emergency services and rescue services are organizations that ensure public safety, security, and health by addressing and resolving different emergencies. Some of these agencies exist solely for addressing certain types of emergencies, while oth ...
s and
mobile TV services such as
Qualcomm
Qualcomm Incorporated () is an American multinational corporation headquartered in San Diego, California, and Delaware General Corporation Law, incorporated in Delaware. It creates semiconductors, software and services related to wireless techn ...
's now-defunct
MediaFLO
MediaFLO was a technology developed by Qualcomm for transmitting audio, video and data to portable devices such as mobile phones and personal televisions, used for mobile television. Qualcomm operated a mobile pay television service, FLO TV, from ...
(channel 55). Additional channels from 38 to 51 (600 MHz band) were auctioned in early 2017, leaving channel 37 as a
guard band
In telecommunications, a guard band is a narrow, intentionally unused frequency band that is placed between adjacent frequency bands to minimize interference between them. It is used in frequency-division multiplexing. Guard bands exist in both ...
between repacked TV stations and more mobile networks, for which
T-Mobile US
T-Mobile US, Inc. is an American wireless network operator headquartered in Bellevue, Washington. Its majority shareholder and namesake is the German telecommunications company Deutsche Telekom. T-Mobile is the second largest wireless carrie ...
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 box
A cable converter box or television converter box is an electronic tuning device that transposes/converts channels from a cable television service to an analog RF signal on a single channel, usually VHF or 4, or to a different output for di ...
es under these numbers are not on the same frequencies as their over-the-air counterparts; there are also
virtual channel
In most telecommunications organizations, a virtual channel is a method of remapping the ''program number'' as used in H.222 Program Association Tables and Program Mapping Tables to a channel number that can be entered as digits on a receiver's ...
numbering schemes in use in
digital television
Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...
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
In NTSC-M countries
Outside North America, channel 37 is actively used in these countries where NTSC-M is used:
* In the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
,
GMA TV-5 in Davao uses UHF 37 as
GMA Network
GMA Network (an acronym of its legal name, Global Media Arts and commonly known as GMA) is a Television in the Philippines, Philippine commercial broadcast network, serving as the flagship property of publicly traded GMA Network (company), ...
's digital channel (ISDB-T) with analog broadcasts on Channel 5. Channel 37 was also used by
UNTV-37 in Metro Manila as
Progressive Broadcasting Corporation's analog channel, with digital broadcasts assigned to Channel 38 (ISDB-T).
* In the
Dominican Republic
The Dominican Republic is a country located on the island of Hispaniola in the Greater Antilles of the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean. It shares a Maritime boundary, maritime border with Puerto Rico to the east and ...
channel 37 is also used for the ''CDN'' news channel
* In
South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern half of the Korea, Korean Peninsula and borders North Korea along the Korean Demilitarized Zone, with the Yellow Sea to the west and t ...
KBS 2TV's analog channel on gwanak-san Transmission station.
In other countries
In these other countries, the
frequency allocation
Frequency allocation (or spectrum allocation) is the part of spectrum management dealing with the designation and regulation of the electromagnetic spectrum into frequency bands, normally done by governments in most countries. Because radio pr ...
for these TV channels is different:
* in the UK (many
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna (radio), antenna with the purpose of sig ...
s used by the
Five network actually broadcast in the past on PAL channel 37; as mentioned below, it was previously used as a local device output channel before Five's launch, and the network had to provide service regarding re-tunes of those devices to a new channel at no cost to the viewer).
* in Western Europe, Channel 37 is used fairly widely as a relay transmitter frequency.
* In Malaysia, NTV7 broadcast in PAL on CCIR Channel 37 (599.25 MHz) prior to analogue shutdown. Currently the frequency is not in use.
* In Indonesia, Channel 37 UHF has been used by many analog terrestrial networks depending on its location, such as
MNCTV for the
Jakarta metropolitan area
The Jakarta metropolitan area or Greater Jakarta, known locally as ''Jabodetabekpunjur'' (an acronym of Jakarta– Bogor– Depok– Tangerang– Bekasi further extended to include Puncak region of Bogor Regency and portions of Cianjur Regenc ...
,
tvOne for
Medan
Medan ( , ) is the capital city, capital and largest city of the Indonesian Provinces of Indonesia, province of North Sumatra. The nearby Strait of Malacca, Port of Belawan, and Kualanamu International Airport make Medan a regional hub and multi ...
,
GTV for
Semarang
Semarang (Javanese script, Javanese: , ''Kutha Semarang'') is the capital and largest city of Central Java province in Indonesia. It was a major port during the Netherlands, Dutch Dutch East Indies, colonial era, and is still an important regio ...
,
TVRI for
Makassar
Makassar ( ), formerly Ujung Pandang ( ), is the capital of the Indonesian Provinces of Indonesia, province of South Sulawesi. It is the largest city in the region of Eastern Indonesia and the country's fifth-largest urban center after Jakarta, ...
, and
Metro TV for
Denpasar
Denpasar (; Balinese script, Balinese: ᬤᬾᬦ᭄ᬧᬲᬃ, ''Dénpasar'') is the capital city of the province of Bali, Indonesia.
Denpasar is the largest city in the Lesser Sunda Islands and the second largest city in Eastern Indonesia after ...
, while in
digital
Digital usually refers to something using discrete digits, often binary digits.
Businesses
*Digital bank, a form of financial institution
*Digital Equipment Corporation (DEC) or Digital, a computer company
*Digital Research (DR or DRI), a software ...
, the frequency now used as
multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource� ...
by
Emtek in
Samarinda
Samarinda is the capital city of the Provinces of Indonesia, Indonesian province of East Kalimantan on the island of Borneo. The city lies on the banks of the Mahakam River with a land area of . Samarinda was one of Indonesia's top ten City qu ...
and
MNC Group in
Mamuju.
Channel 37 is not the same frequency as it is in the countries using the System-M/N standard. At least in the UK, 606–614 MHz is reserved for radio astronomy.
The UK's namesake "Channel 37", while different in frequency, was formerly part of a small group of channels reserved for non-broadcast purposes such as
RF modulators for output devices such as
game console
A video game console is an electronic device that outputs a video signal or image to display a video game that can typically be played with a game controller. These may be home consoles, which are generally placed in a permanent location conne ...
s and
videocassette recorder
A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other AV sources and can play back the recording after rewinding. The use of a VCR to reco ...
s. The UK-named 34-37 channel range is no longer reserved in this manner.
In Japan,
UHF television channel frequencies are offset by one channel compared to North American channel naming convention. Japan's channel 36 is in use by
TV Asahi
JOEX-DTV (channel 5), branded as , and better known as , is a Japanese television station serving the Kanto region as the flagship station of the All-Nippon News Network. It is owned-and-operated by the a subsidiary of , itself controlled by ...
in some regions.
Global UHF TV allocation table (605–615 MHz)
This Radio Astronomy Allocation is between the following wavelengths:
* 605 MHz = 0.49552 m = 49.55 cm
* 615 MHz = 0.48747 m = 48.75 cm
* Assume either a 100 kHz or a 250 kHz guardband with respect to this allocation.
DVB-T adoption note : The tables above are not accurate for nations that have adopted
DVB-T
DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Fe ...
. The frequencies for audio and video are merged with DVB terrestrial television. The new DVB frequencies are rounded off to an even number in MHz as a general rule.
National arrangements for radio astronomy different from ITU-R
National arrangements for radio astronomy different from ITU-R Radio Regulations
Central & Western Europe
* Austria: no allocation - only mention of No. 5.149
* Bulgaria: no allocation
* Belgium: assignment to radio astronomy (shared with active services)
* Finland: no allocation
* Estonia: no allocation
* Iceland: no allocation
* Liechtenstein: no allocation
* Luxembourg: no allocation
* Netherlands: primary status
* Portugal: no allocation
* Spain: no allocation
* Sweden: no allocation
* United Kingdom: no reference to No. 5.149
Rest of World
* Armenia: no allocation
* Russian Federation: no allocation
* Turkey: no allocation
[Both channel 37 and channel 38, which covers the relevant frequency range in Turkey, are being used by TV stations. ]
* New Zealand, Maori TV and others (not allocated to Radio Astronomy at all)
References
External links
North America
FCC database for Channel 37 had shown possible usage conflict with Mexico but now has the channel entirely clear in Canada, the U.S.A. & Mexico.
US FCC's attack on Channel 37AE5D.com Channel 37 - The last Empty Channel
An article about channel 37 and channels above 69
Astrophysical importance of the band 608 - 614 MHz
''Time'', 10 May 1963
FREQUENCIES ALLOCATED TO RADIO ASTRONOMY USED BY THE DSN McAdams On: Channel 37
Rest of World
NZ Long Term Digital TV Plan{dead link, date=November 2016 , bot=InternetArchiveBot , fix-attempted=yes
Broadcast engineering
37
History of television
Fictional television stations