Dish diameter. A 10-foot dish has an aperture of 10 feet. The beamwidth of a dish antenna is the angle of sky which can be illuminated (picked up or sent out) by the dish. Within that arc satellites can be seen from the TVRO dish. Large dishes have narrow beamwidths, which reduces noise form its sides. Samll dishes have wider beamwidths, meaning that they are noisier but easier to aim.