Again it depends
The ability to receive a signal at all times is dependent on a number of factors
1) could be an FTA transmission, then it scrambles for certain copyright reasons - eg Canale5 Italy
2) The satelite itself may be moving relative to the earth, in any direction (up down, left, right) and so the focal point of the dish may not be correct at all times
3) The satellite could also have an elliptical orbit, meaning the density of signal may change on a daily basis
4) The broadcaster may request a reduction to the power to the particular transponder at certain times, to prevent the signal being received outside the designated area
5) The ground conditions near the dish may alter during the day, air temperature and/or humidity, which affects the dish parabola and/or LNB noise figure
6) Someone may be hanging out washing in front of the dish ?