Originally posted by Old Satellite
The safest option I would reccomend at your location is a 3.0 mtr prime focus (solid) with a 0.5-0.6 db lnb
This is absolutely right but if he's on a tight budget and doesn't mind missing a couple of dozen channels, he could get away with, say, 1.8 metres or less. Depends very much on the type of dish and LNB and on the alignment of both. Also on the Sky Digibox which should be a Panasonic TU-DSB30 for best results, although others (eg. latest Grundigs) are almost as good.
It's not a problem of *sensitivity* but of tuner *selectivity* - the ability to "see" weak signals while strong signals are blasting in.
Many Digiboxes get "blinded" by the stronger signals under these circumstances. Basically, in southernmost Europe, a 1m dish is good enough for half the channels (southern beam). So if you use a 3m dish for the weak northern beam, you are actually increasing the dish area from around 0.8 sqm to around 7.8 sqm. Obviously the already adequate southern beam signals are now being multiplied nearly TEN times! You have the equivalent of trying to see a candle flame behind a car headlight. Most Digiboxes can't hack it.
As Astra 2D signals are weaker still, the chances of getting, say, ITV are extremely slim.
BTW there are still a few big "C-Band" dishes being hawked around. These usually have quite big holes in the mesh. They are totally useless for Ku-band so don't be conned.
Martin