User:SWalkerTTU/Sandbox

North America cable television broadcast band
NOTE: For analog services, luminance carriers are at 1.25 MHz above bottom frequency, audio carriers 0.25 MHz below top frequency


 * Channels T-7 through T-14 are sub-band channels and are not used for normal television channel distribution. These channels are used for sending video back to the cable television headend, such as by public-access television stations on a cable tv system.  They are also used by cable modems for sending upstream data to the headend's CMTS.


 * Channel 1 frequency assignments, where provided, are non-standard. If a channel 1 were inserted (A-8) between channels 4 and 5, channel 5 would need to move 2MHz off-frequency, pushing channel six 2 MHz off-frequency into spectrum needed for FM stereo radio. Any assignment placing Channel 1 in its historical location before VHF Channel 2 would also be problematic, as the last cable reverse channel (T-14) now occupies frequencies from the defunct terrestrial Channel 1. Most systems that provide a (named) "Channel 1" will therefore either alias "1" to some higher converter channel (such as 101) or to a digital virtual channel.


 * Cable channels 2 through 13 operate on the same frequencies as broadcast television (the VHF band). They were assigned by the FCC pursuant to NTSC.  The other channels were assigned by cable television operators.


 * Cable channels 65 through 94 and 100 through 125 operate on approximately the same frequencies as broadcast television (the UHF band). Ultraband 65 and up will appear to be UHF TV 14 and up on most non-cable-aware analogue television receivers; as each ultraband channel is exactly 2 MHz below a standard UHF TV channel, a slight fine-tuning of mechanical UHF tuners is all that is required to shift this block squarely onto the UHF dial.


 * Cable channels 95 through 97 (90 - 108 MHz) operate on the same frequencies as FM radio, so cable companies offering FM radio will not show TV programming on these channels.


 * Cable channels 98 and 99 (A2 and A1, 108-120 MHz), if used, have appeared as channel 00 and 01 respectively on some converter boxes


 * Digital cable channels are often numbered starting at 100 or 200, but these are virtual channel numbers and do not correspond to used frequencies.


 * Digital television receivers with integrated QAM tuners use ATSC conventions for numbering channels; unlabelled channels would appear as a main channel number, separated by a dot or dash, then a digital subchannel number. For instance, this may display as a physical converter channel number, a dot or dash, then a virtual channel number as it appeared on a digital cable set-top box. As there is no requirement that any specific convention be used to number digital or virtual channels, numbering is at the discretion of the cable operator.