Yes.
The regulations provide a "common sense" approach when installing radio systems that are associated with a dual path signaling system. If insufficient service is obtainable within the protected area, the antenna may be re-located outside of the area. External installation is permitted in these circumstances. Sensible precautions should be made to protect the antenna from attack. Remember that the circuit is monitored and an attack on the antenna that disrupts service delivery will be notified to the ARC within 3 minutes
(Note this time applies to WebWayOne services, other providers times may differ).