Pine Gap is America’s most secure and most secret facility. It is located near Alice Springs in Central Australia, and has long been the center of extensive area UFO activity.
The famous Shuttle Mission STS-48 video that appears to show UFOs clustering around the spacecraft also features a pulse of some sort of energy that is directed upward from the ground, which causes the unknown objects to move away at high speed.
The area of the earth from which the beam emanated would have been central Australia, almost certainly Pine Gap.
This article, published first in 1996, describes very similar phenomena being witnessed from the ground by local people in the base area.