Ever wonder why VHF channel 1 and UHF channel 37 aren't used?

[Retail Fan+ (Justin Hill)]

Here are your answers:


Channel 1:

The reason Channel 1 no longer exists on TV is because during the
pioneering years of television in the 1940's, the Federal
Communications Commission (FCC) dedicated Channel 1 to mobile land
services.

Prior to that, between 1938 and 1940, TV was allocated 19 channels
(from 1-19) with frequencies ranging from 44 to 294. Between 1940 and
1948, following a number of redistribution of frequencies, the
frequencies were finally redistributed amongst the channels and the
44-50 Mhz range which was allocated to Channel 1, became allocated to
FM. And the number of channels was reduced from 19 to 13.

After 1948 the FM frequencies were changed from 44-50 Mhz to 88-106
(later 108) Mhz. Channel 1 was then freed to be allocated to mobile
land services. But the Channels were never renumbered.


The following is an excerpt providing a better understanding:

“In 1945, the FCC decided to move the 42-50 Mcs Original  FM Radio
Band to 88-106 Mcs  (later 88-108 MHz).
Because FM broadcasting would be vacating 42-50 Mcs, TV Channel 1 was
moved down to 44-50 Mcs in the old FM band...”
(...)
“...Although several television stations were scheduled to move to the
new Channel 1, no TV stations ever broadcast on  44 - 50 Mcs.
It could not be used immediately because it was necessary for all
existing FM stations to move out of the 42-50 Mcs spectrum to the
88-106 Mcs FM Band.
When all the FM stations finally did move, the FCC decided to
re-allocate 44 - 50 Mcs to other services.  Thus, Channel 1
disappeared.
There was no renumbering of the remaining channels.”

Channel 37:

Channel 37 is a purposefully unused television channel in countries using the M and N broadcast television system standards. The frequency region set aside for Radio Astronomy is really from 600 MHz (0.5m) to 620 MHz (0.4835m) -- but 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).

Channel 37 in System M & N countries specifically occupies a band of UHF frequencies from 608 to 614 MHz. This band is particularly important to radio astronomy because it allows observation in a region of the spectrum in between the dedicated frequency allocations near 410 MHz and 1.4 GHz.

One radio astronomy application in this band is for very-long-baseline interferometry.

In 1963, when there were very few stations in the UHF band, the US 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.

Some nations, for whatever reason may not only fail to set aside this region for Radio Astronomy -- but may outright allot broadcasters channels in this spectrum region. In New Zealand (as of 2016), Maori Television has been given 2 channel allotments nationwide in this frequency region.

In the digital broadcast age...

The ATSC standard allows for a major virtual channel number from 1 to 99, followed by a separator ('.' or '-') and a digital subchannel number from 1 to 99 (for broadcast TV) or 1 to 999 (datacasting or cable TV). As such, it does not preclude the creation of a virtual channel 1.1 or a virtual channel 37.1:

    "The major_channel_number shall be between 1 and 99. The value of major_channel_number shall be set such that in no case is a major_channel_number / minor_channel_number pair duplicated within the TVCT."

However, the specification does not define any criteria to determine whom (if anyone) could ultimately be assigned the 1.1 virtual channel series for over-the-air broadcast in a local community; it merely defines a procedure to allocate virtual channels 02â€"69 based on holders of the corresponding (former) analogue NTSC licenses and designates virtual channels 70â€"99 for possible use to carry additional, unrelated programming via the facilities of these same broadcasters. (99 was used briefly by the now-defunct USDTV, for instance, although such applications are rare.)

KAXT-LD of San Jose, California, won permission to use digital virtual channel 1.x, effective September 1, 2009, on technical grounds, asserting that existing virtual channel numbering (22.x) conflicted with that employed by educational broadcaster KRCB in Cotati, California.

[TheFugitive]

In the analog TV days Australia actually had a Channel 0!