The wirless cameras have some security in it,so any other person will not be able to watch it.Cheap camera are available as low as $70 with a good range.There are ways to haveyour own RF video telemery system but will be much costlier than off the shelf wireless cams
We have all the frequencies inour country licensed.We use several systems one such we call Radio Planning and survey system,which gives a topographical view of our COmpany ,and frequency spectrum,range etc can be graphically superimposed upon it by also factoring in the rough Signal...