Ian Jackson wrote:

In message , Geoffrey S.
Mendelson writes
David Looser wrote:

Of course if you are only looking for local coverage you could run several
networks in the available spectrum. But the argument was that VHF gave
better national coverage than UHF. If that is the aim then, I suggest, you'd
need both Bands 1 and 3 to give truly national coverage of just one network.
Its probable that it would be possible to add a second network that only
covered the main population centres, as Analogue Channel 5 did on UHF.

I don't know how well UK sets worked in the 1960's, but US TV sets were
not capable of receiving adjcent channels at one time, so they were not
used. For example, channel 2 was used in New York City, while the nearest
channel 3 station was in Philadelphia, 90 miles away and too far to be
received without a large antenna.

I think the next one up was 5 in NYC and 6 in Philly.

Generally, UK (and even European) TV sets had a hard time with adjacent
channels. Like the USA, the off-air broadcast channels were arranged so
that, within the normal service area, there would never be an adjacent
channel which was anything like as strong as the channel(s) intended for
that area.


That was a problem with very early vacuum tube CATV trunk amplifiers
that were run single ended. They generated a lot of IMD. Even '60s
solid state push-pull Trunk amps had no problem with adjacent channels.
CATV converters only made it possible to add more channels to broadcast
only TV sets. Some converted to a low VHF channel, (Hamlin, Jerrold,
Oak) and others (Eagle) converted everything up to the UHF band. I
repaired in excess of 10,000 CATV converters in the '80s, in a four year
period along with all of the head end equipment.


--
You can't have a sense of humor, if you have no sense.