Does anyone know how "The Weather Channel" distributes the regional
> forecast information (as seen during the "local on the 8's" portion)
> to the local cable companies. Is it data in the vertical interval of
> the TV signal, or do they use internet connections (broadband,
> dial-up), or some other communication channel?
The local-weather data is distributed by satellite along with the primary video signal. It's distributed simultaneously over several different satellites in different formats; a list of more-or-less current assignments is at
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(scroll down to Weather Channel).
Three typical cases:
AMC-ll transponder 13 (3960 MHz, Vertical)
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Video is distributed as analog NTSC; audio, local-weather data, and other metadata are encoded on subcarriers and the combined signal is encrypted with the VideoCipher II scrambling system. At the headend, the signal is decrypted with a VideoCipher II decoder and sent to a so-called "Weather Star", a proprietary (and very expensive) rack-mounted PC that decodes the local-signal data and inserts it on cue in place of the default video (maps of various parts of the country showing rudimentary forecasts) received from the satellite. If the Weather Star is not used, default video passes through. This format is now all-but-obsolete, but presumably it's still available for the benefit of smaller CATV systems and the lodging industry, many of whom don't use Weather Stars.
AMC-10 transponder 24 (4180 MHz, Horizontal)
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Video, audio, local-weather data, and other metadata are multiplexed into a single data stream which is then encrypted with the DigiCipher scrambling system. At the headend, the signal is decrypted and sent to a digital version of the Weather Star. This format is now used by most CATV systems and many high-end hotels and casinos.
DirecTV 1R/2/4S unknown transponder
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Video, audio, and metadata, along with several other video signals and their respective audios and metadata, are all multiplexed into a single data stream which is then encrypted with the DirecTV's proprietary scrambling system and modulated onto one of DirecTV's transponders. There is no local-weather data; all DirecTV subscribers get the default video. Echostar (Dish Network) uses a similar proprietary scheme. Presumably, Voom did so too before it ceased operations.
Neal McLain