Originally Posted by electrictroy
Neither does Cable. They could easily pass the DTV stream straight from NBC (for example) to each person's home. There's plenty of bandwidth on the cable's waveguide.
And many cable companies DO pass the source signal without modification.
If they have that much excess bandwidth, I wonder why they are so dead set against carrying each local station's analog (for the present) and digital streams, including the HD and the sub channels, as well as offering more of the HD streams from all the program providers? They certainly seem to be spending a lot of time and money fighting the Must Carry provisions for some reason.
I think that with a little research, comparing apples to apples, you will find that the amount of data (analog or digital) you can push along a piece of coaxial cable at practical power levels is a mere fraction of what you can push along a piece of fiber. Else I daresay we wouldn't have spent all the money we have spent on fiber systems for our cameras, we would be pushing 1080i down the same triax (a good grade of RG-11 with an extra shield) we have been using for 30 years. Fiber is a pain in the butt to us in our application owing to its relatively fragile nature, having to run separate conductors for power, the difficulty in reterminating cable in the field, expense of the cable and the connectors, and so forth. And Ma Bell would probably still be using the coaxial cable it used before the advent of microwave and then light guide, now more popularly known as fiber optics.
As to your statement that many cable companies do onpass the inbound signal without compression, well, maybe NTSC analog signals, but in my experience across the county, this isn't the case. It simply isn't possible to squeeze that much sausage into that size casing.