The main radar at Gib (was a Watchman last time I was there but that was years ago) is situated on the northernmost peak of the Rock about 1,000ft above airfield elevation and as such has an 'underhead'. I dare say the fibre optic cables could be damaged by rockslides but you would expect them to be protected against that.
There was also a PAR for westerly approaches near the tower and an ACR430 on a small 'mole' off the edge of the runway for easterly approaches (SRAs).