Jerry Stuckle wrote:
That was the major impetus over here to switch to digital - to free
up major bandspace in the VHF and UHF spectrums.

The 'freeing-up' is because each QAM multiplexed transport stream
carries typically up to 6 TV channels and 6 high-quality stereo radio
channels.


Ah, so the channel is effectively only 1Mhz wide then.

That is only an "average" that you get when you divide the total bandwidth
by the number of TV programmes transmitted.
As multiple TV programmes are transmitted on a single channel,
that occupies the width of a classical analog channel that could
transmit only a single programme, more programmes can be put in
the same bandwidth.

However, to receive one of them you really need to receive the
entire channel (several MHz wide), so all link budget calculations
should be based on the full bandwidth. Later, the receiver throws
away most of the bits it has received and decodes only the information
for one of the TV programmes.