A satellite dish can be circular, or oval shaped and can range from 35cm to 11 metres in size. KU band dishes are generally smaller than 1.5 metres while C band dishes are always over 1.5metres in size.
Foxtel generally uses 65cm dishes around Australia, IMC recommends that customers use a 85cm dish. The reason being that because all satellite signals in Australia are digital, at a set signal level the service start pixelating and then will cut out. With satellite dishes what you need to do is to get over this level as much as possible so that you have large a buffer as possible against certain environmental conditions.
When it rains you lose signal quality determining of the strength of the rain. The higher your signal buffer, the harder the rain must be before your service will cut out.
IMC warns you to be careful when selecting your satellite service as it is easy to get over this level but the quality of equipment and the installation will determine how big your buffer is against rain.
The ironic part is that most people watch TV when it is raining as you are confined to your house and nothing could be more frustrating than your satellite service not working because it is raining.