Why I use a Mac, anno 2006 3719

One of the myths surrounding the modern digital satellite signals is that it is overly sensitive to rain fade.

In the Bad Old Days of C-band and Ku-band analog video, a small change in RF C-N would directly correlate to a similar small change in baseband S-N. As the signal got noisier, the picture got a little fuzzier. It was relatively easy to peak the RF because you could easily see the results. When you were on boresight, you KNEW it.

Digital uses relatively long convolutional codes, such that the difference between a BER of 10**-7 and 10**-4 might be only 2 dB, combine that with the tense compression needed to get video into the bandwidth allocated, and the difference between "full quieting" and "total collapse" might be a half a dB. People want smaller aperture antennae, so the industry has adopted more agressive fade-margins.

But the big failure is: Peaking the RF requires actually reading and understanding the instructions (or the underlying technology). If you just grip the edge of the reflector and jiggle it until you have a viewable signal, you might be right at the hairy edge of the threshold. The signal is corrected to perfection, so you think "I must have it pointed in the right direction." If you had taken the time to accurately position the system, you would have plenty of fade margin for all but the *strongest* storm cell.

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Computer software consists of only two components: ones and zeros, in roughly equal proportions. All that is required is to sort them into the correct order.