I was with someone who tried to tell me they bounce the signal from building to building until it gets to the CN Tower, but that sounds like bull to me.
Not BS, microwaves can indeed be reflected off say a building or a mountain ridge or other large surface and get a signal of sufficient strength when there is not a clear line of site route avalible. In fact some fixed commercial microwave links utilize large passive billboard size structures mounted on high hill tops to allow linkage where line of site is not possible.
I have no doubt that the operators of those mobile TV remote vans have learned many tricks to establish a link when out in the boonies where clear paths are not possible. http://en.wikipedia.org/wiki/Non-line-of-sight_propagationhttp://en.wikipedia.org/wiki/Passive_repeater