[BC] HDTV

[FrankGott@aol.com]

In a message dated 2/8/2006 3:55:10 PM Eastern Standard Time, wa2mct at juno.com 
writes:

<< 
 Who decides what channel position the local ends up at? Normally
 different (on an analog cable system) from their over the air channel. 
  >>
Remember that cable began with just 12 channels.  Tradition dictates that the 
over the air channels end up on the lowest number channels, those in the VHF 
band.  They've remained there as cable systems upgrade their transmission 
plant over the decades.  The lowest numbered channels are also the most basic 
tiers offered.  So called "lifeline" cable for areas with poor over-the-air 
reception.  The UHF stations are moved to the basic level giving all stations 
parity.  

The channel numbers of the V's are moved to avoid herringbone and other 
interference with the over the air signal.  That's also why there's a slight shift 
in frequency from the air signals, hence the air/cable setting on modern TVs.  
A loose connector can cause severe interference, what's known as ingress in 
the industry.

Having broadcasters grouped makes sense.  Comcast groups similar channels 
such as sports and news on the system here in Pittsburgh.

Frank Gottlieb
cable guy in a previous life