How do you block your neighbors satellite TV signal?

It would appear at first reading of the question that this is at best a somewhat un-neighbourly act if the objective is to block incoming satellite signals. If that is the objective, it also happens to be an offence in many jurisdictions under various telecommunications laws.

However, it the question concerns interference from a neighbour's equipment, that is rather different. Equipment in close proximity to other systems can sometimes affect operation and there are numerous reasons why it might happen. In most cases it will be caused by an equipment fault but the fault can be either in the system causing the interference or in the equipment that is showing the results of interference. As a starting point, check all the equipment for correct operation and also check mains and signal cables. Cables between devices can often generate more unwanted signals than the equipment itself. If there is no obvious fault to be seen, it may be time to bring in a professional to diagnose the problem before going further.