That depend what you want to watch, a single satellite or want to track difference satellites. if use it as fixed dish, much simple, any Digital box will do, if you need more satellites programming, need an older analog receiver for move the dish and an actuation arm.
Its wise to have a 24" arm then the 18". A 24" arm is better hold when you encounter the strong wind force. the dish can also give you more room to track more satellites.
If you hear sounds from the receiver, the problem most come from the receiver, if the cable has problem, it only show no signal to your receiver. But however, looks like your multi switch got fried. diring you make the connection.