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It's all about bandwidth

There may be a contest today, but in a few years, cable will beat the socks off of satellite in perhaps every area except price. And the reason lies in physics.

Right now, broadcast satellite TV uses a relatively narrow slot in the RF spectrum from 12.2 to 12.7 GHz. That's a 500MHz band. Given that you need about 6MHz for the decent transmission of a STANDARD television signal, that leaves room for only 83 channels, much fewer for HDTV.

Enter compression, however, which lets them cram more information into the signal, at least so it seems to the eye. (I don't know how effective that compression is, sorry.) On the other hand, I'm fairly certain that a lot of that extra bandwidth gets consumed by error correction. If you remember the old analog satellite TV with the 12-foot dishes and cryogenic preamps just to squeeze out a usable signal at 3-point-something (I think) GHz, you know the the newer generation 18-inch dishes with their cheap block downconverters sweating it out at 4 times the frequency are living on the hairy edge of physics and relying on error correction to pull useful information out of all that noise. Those of you who have testified about reception problems during bad weather speak of this.

The point is, that bandwidth is all there is. There is a second 2GHz band allocated up in the 80-90GHz range, but using that would mean buying all new (and probably very, very expensive) electronics. Plan on that after you pay off your 172" plasma screen. Broadening the spectrum would involve either sacrificing other services (bye-bye GPS?) or extending allocation into higher frequencies. But that second option really isn't much of one since we're already running into the infrared and its problem transmitting through atmosphere. Enter physics again.

Cable, on the other hand, has no theoretical limit on bandwidth. Modern copper systems with fiber optic backbones are pushing 850MHz in bandwidth, which right away translates into almost twice as much capacity. And since noise is less of a problem, it can rely on less robust error correction (I don't know that it actually does) which leaves even more bandwidth open.

The future I was talking about comes when fiber optic comes straight to your door. Consider 20GHz of bandwidth feeding right into your cable box. That's about 3300 channels of standard definition TV or 100 of HDTV. Add compression, and who knows? 10,000 channels? If we want more, we can always double up fibers.

That's just TV. If you're talking Internet, there's another whole arguement in favor of cable: uplink speed. Well, same argument, different direction.

Anyway, satellite will never be able to keep up with that.

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