'Re: [OT] 240V in USA, TV in GB [way, way OT]'
Nigel Goodwin opined:
I presume to use 12 VHF and dozens of UHF transmitters there must
be large areas that don't have coverage, otherwise they would be
lots of places where two transmitters on the same channel would
cause too much interference with each other to provide viewable
No, Nigel, actually with 12 VHF channels, not to mention channels 15 to 83
on UHF, the FCC (and CRTC in Canada) ensure that no two same frequency
transmitters are licensed within interference range. In practice, in a few
very dense metropolitan areas, such a NYC and Toronto-Niagara Falls in
Canada, on days (usually nights) of unusually high propogation there can
sometimes be a bit of a problem with this "co-channel" interference, which
is one of the reasons that cable TV took off big-time in the metro areas
early on, even though you would have expected only the rural regions to
CIAO - Martin.
Nigel Goodwin answered me with:
<SNIP> As for expecting cable in rural areas, the situation as I see
it is exactly the opposite - the cable companies are only interested
in cabling areas with large population densities.
This is true today, but in the early days of cable it was expected to be of
commercial value only in rural, poor signal areas. No-one anticipated that
cable would be used to bring 50+ channels to an area that already received
8-10 off-the-air channels clearly. It was instead expected to bring those
8-10 channels to the outlying regions.
The other thing that has shifted the equation is the emergence of satellite
TV. As you state, it is no-longer cost effective to cable the outlying
regions when for a lower cost per house each home can install a satellite
dish (especially the new small dishes). But early on, when satellite
reception didn't exist, or was in its infancy, you either paid for cable in
the fringe areas, or you didn't get TV at all. I remember when I was about
15 or 16 (that is, 25 years ago), when I visited a small shipbuilding and
skiing town in central Ontario, Collingwood, they received one station with
an aerial fairly well, and one atrociously. Most people who could afford it
subscribed to cable.
Things have changed a great deal in 25 years.
CIAO - Martin.
Herbert Graf noted:
Actually to nitpick, UHF is from channels 14-83, although most TVs
don't go beyond channel 69, originally UHF only went up to 69, but then
they expanded it to include up to 83, however over the air there is
alot of interference at these higher stations, at least here in Canada.
You are of course correct, a slip of the finger caused me to type 15-83
instead of 14-83, but I confess I didn't realize that channels 70-83 had
been reallocated for the cellular frequencies, as noted in another post.
CIAO - Martin.
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