Originally Posted by Unexpat

Any dish over 1.8m that has a solid parabolic reflector is going to need secure fixing to concrete and lots of it, for that one time in a while that the winds exceed 100 kmh. Don't let anyone tell you otherwise. When winds gust over 100 kmh the forces exerted per square metre are fierce.

Size of dish needed is totally dependant on which satellite you're aligned with and it's associated footprint. This thread has already given good links for these maps. The "further south, bigger dish" rule goes totally out of the window if you want Astra and you're in Murcia, or Alicante, for example. Footprints are not very uniform; use the maps.

I take it that "High Grain" is a typo and should be "High Gain", measured in decibels (dB) presumably. There are two aspects to good reception, the gain of the antenna/dish/LNB combination and the selectivity and noise of the satellite receiver/decoder box, if I remember my electronics correctly.

Different satellite receivers have slightly differing performance characteristics in the above departments, but these differences really only matter where the signal is borderline, e.g. where the antenna gain is on the lower side.

Mass-produced consumer electronics are bound to have varying results due to the fairly wide tolerance levels of some of the components and the variability of Quality Control.

At the end of the day, there is no substitute for a properly fitted dish of the the right size. Anything else is just marketing speak, in my opinion.