Indoor repeaters for a small area is mainly to solve weak or no signal coverage. With open plan office areas or an open café et cetera, the signal strength from the outdoor antenna directly affects the efficiency of the indoor coverage. It’s important to choose the location of the outdoor antenna carefully on the roof for optimum performance and to isolate so that no oscillation will occur.
In order to avoid signal oscillation on the repeater, there needs to be a certain distance between the outdoor antenna and indoor antenna, i.e. a vertical distance of 6 to 8 meters or a concrete wall as an obstacle.