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Channel 37 is an unused television channel in countries using the M and N broadcast television system standards. Channel 37 occupies a band of UHF frequencies from 608 to 614 MHz, frequencies that are particularly important to radio astronomy because they allow observations at a frequency 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.〔http://sites.nationalacademies.org/xpedio/groups/bpasite/documents/webpage/bpa_048869.pdf〕 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. == Allocation issues == Reservations non-exclusive * The Canadian Radio-television and Telecommunications Commission (CRTC) also enacted such a ban on channel 37. * It appears that Mexico ''may'' also observe a similar ban on the use of this TV channel, if only informally. * Guatemala has a ban on Channel 37.〔(Guatemalan UHF TV bandplan )〕 * Most NTSC System-M countries have an informal ban on channel 37 as well. Since July 2000, channel 37 may also be used in the U.S. for medical telemetry equipment on a co-primary basis. This 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. Even this seemingly low power level can be troublesome for radio astronomy, 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 by the 1980s mainly for AMPS mobile phones and, in June 2009, channels 52 to 69 for mobile phones, emergency services and mobile TV services such as Qualcomm's MediaFLO (channel 55). Certain channels, 14 through 20, are used for land mobile communications in some large metropolitan areas in the U.S. 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「channel 37」の詳細全文を読む スポンサード リンク
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