linux at thehobsons
Jan 5, 2013, 1:32 AM
Post #6 of 21
George Nassas wrote:
>Where are you lattitude-wise? I think it it gets tougher to use the small dishes the further north you go.
It's more important where you are in relation to the "illuminated" footprint of the signal. I only know a little I've picked up over the years, and it's all European, but the principles will still apply. When a sat is put up, the transponders will be designed to focus the signal over a defined area - partly to control who an receive the signal, partly to maximise efficiency (signal sent where you don't want it is wasted power).
So imagine you are sat up in geostationary orbit and shine a torch down at earth. You can control where the patch of light lands, and by clever design of the optics, the shape of the illuminated area. Considering North America, if a service was aimed at (say) only Canada, then the transmissions would be aimed at Canada (so Canadians would get s good signal with a moderate size dish) - but northern USA would get some signal (it's not a sharp cutoff at the edge of the area), while sourthern USA would get very little (you'd need a HUGE dish to get a signal).
As a practical example, the guy tat runs the satcure.co.uk website lives in Greece now (well actually, on an island there) which is a much lower lattitude thant eh UK. The ex-pats there have been able to get UK satellite TV by using a large dish (about 1m IIRC vs 60 or 80 cm in the UK) because the signal is boardcat over a wide area and they are on the fringes of it. Recently some services have moved/are moving to a new sat/transponder which has better control over the footprint and people are finding that channels disappear as the services move. As they are out fo the published coverage area (so no coverage/signal strength information - see below), it's going to be a trial and error process to work out how big a dish will be needed to get a signal back - it may be that there's so little signal that the required dish would be far to big to be practical.
You may have to dig around, but I know some of the operators publish sharts showing the signal strength in their coverage area. Usually it's done "weather isobar" style, with lines setting out the areas that can receive a signal with a given size of dish. If you can find such a chart then it should answer your questions.
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