Total posts : 45366
Well, one way to look at it is that two Rangemasters located in close proximity would produce the sum of their output powers. Field strength and therefore range would increase by the square root of 2, or 1.41. That may not be as good as what you would get by spacing them, but it is still significant enough to warrant two transmitters, if you have the money to spend.
Locating the transmitters on a roof will open you up to FCC scrutinization, ala the NOUO issued to a broadcaster who apparently had 4 Rangemasters on a roof.
I say, go for it. If you get an NOUO, just stop operating and tell that to the FCC. The case will be closed and you won’t get any of the fine or imprisonment stuff that scares so many.