Posted by Alan on 01/02/06 04:09

In article <2v9gr1hgomp3li7piv2f0nbi8o566lijap@4ax.com> Roy L. Fuchs <roylfuchs@urfargingicehole.org> writes:
>On Sun, 01 Jan 2006 18:59:34 GMT, John in Detroit <blanked@blank.net>
>Gave us:
>
>>
>>The only difference is the signal levels and noise levels which are
>>acceptable.
>
> No shit!
>
> Why do you think that we now use an 18" dish for satellite reception
>when, ON THE SAME BIRD, with analog it required an 8 foot dish?

Which specific satellites are you talking about?

The direct broadcast satellites on Ku band are generally running more
power, or more directional spot beams to the surface of the earth than
even the previous Ku satellites. Getting digital signals from the non-
DBS satellites is said to normally require dishes of 30 - 36 inch size
on Ku band.

The analog signals that required an 8 foot dish were on C band. Those
lower frequencies required a larger dish to get a narrow enough beam up
to separate the signals from adjacient satellites.

The digital signals on C band generally required slightly better receive
systems than the analog signals, since they were transmitted at lower power
to keep the satellite transponder operating in a linear mode.


> Why can we pipe over 500 channels of programming through THE SAME
>BIRD, when we used to only get two per transponder, for a total of 48
>channels maximum?

Because they are compressed to much lower quality.


> Same bird, same power output, different signal content. Twelve
>channels PER CARRIER instead of two. How did we accomplish this feat?

If you reduce the quality, you can squeeze more channels in.

Alan

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