hoss

I have a 4 camera wireless reciever and can only get 3 cameras to come in. it is a 5.1 system.The antenna for the system is in line of sight. I do have a burger king and mcdonalds between my cameras and reciever that are useing 2.48 system. does any one have any suggestions on how to get the 4th camera up and running.

any suggestions ?