(Appendix to page ‘Filling the spacethat Worldspace has left… at least to some extend’)
The frequencies that can be
transmitted via satellites (or terrestrially) has been split into different
ranges and systematically designated so that they can be distinctly referred
to. The frequency range for satellite transmissions fall under what are known
as ‘microwave’ (from 1 to 40 GHz), which are further subdivided into 'bands' designated as L, S, C,
X, Ku, K, and Ka.
Different bands are used for
different kinds of transmission, of which, only the ones relevant to this write
up are explained below:
- L-band (1-2 GHz): WorldSpace (1.452 – 1.492 GHz)
- S-band (2-4 GHz): The SDR’s of Sirius (2.320 – 2.3325 GHz) and XM (2.3325 – 2.345 GHz)
- C-Band (4-8 GHz): TV transmission – used by TV channels for original broadcasting, to be picked up by cable TV operators and DTH service providers. This band has the advantage of signals not being affected by rain, called ‘rain fade’, that Ku-band has a disadvantage of – that's why your DTH TV service (which is in Ku-band) goes off when it rains, but not your cable TV service (whose source is in C-band).
- Ku-band (12-18 GHz): DTH services. This band has the advantage of being able to do with small diameter dish antennae – the DTH dish on your roof top (unlike C-band which requires those large diameter dishes found on the TV cable operator’s roof top).
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