Channel 37: Difference between revisions

Channel 37 is an intentionally unused

History

Channel 37 in

One radio astronomy application in this band is for very-long-baseline interferometry.^[1]

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,

In 1963, the Federal Communications Commission (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, Channel 37 has never been used by any over-the-air television station in Canada or the United States.

The 2016-2021 repack left no North American stations above UHF 36.

The low-power

Allocation issues

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.^[3]
• 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

Since July 2000, Channel 37 may be used in the US for medical telemetry equipment on a co-primary basis.^{[clarification needed]} 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.

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

In NTSC-M countries

Outside North America, channel 37 is actively used in these countries where NTSC-M is used:

• In the Philippines, GMA TV-5 in Davao uses UHF 37 as GMA Network's digital channel (ISDB-T) with analogue broadcasts on Channel 5. Channel 37 was also used by UNTV-37 in Metro Manila as Progressive Broadcasting Corporation's analogue channel, with digital broadcasts assigned to Channel 38 (ISDB-T).
• In Trinidad and Tobago, WIN-TV is broadcast on Channels 37 and 39, using NTSC
• In the Dominican Republic channel 37 is also used for the CDN news channel
• In South Korea KBS 2TV's analog channel on gwanak-san Transmission station.

In other countries

In these other countries, the frequency allocation for these TV channels is different:

• in the UK (many
  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 analog shutdown. Currently the frequency is not in use.
• In Indonesia, PAL Channel 37 UHF (599.25 MHz) has been used by many analog terrestrial networks depending on its location, such as MNCTV for the Jakarta metropolitan area, tvOne for Medan, GTV for Semarang, TVRI for Makassar, and Metro TV for Denpasar.

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

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 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. 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^[5]
• 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 37
• AE5D.com: Channel 37 - The last Empty Channel
• W9WI.com: An article about channel 37 and channels above 69
• craf.eu: Astrophysical importance of the band 608 - 614 MHz
• Spare That Channel, 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^{[permanent dead link]}