Dipole Antenna, Transmitter, Space Surveillance Fence


Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

This is a spare transmitter dipole antenna used in the Space Surveillance Fence. The system's three transmitter stations each had many hundreds of these antennas. Located across the southern United States, the three stations emitted a continous wave of radio energy in a narrow fan-shaped pattern. Together the beams extended about 5,000 miles from west to east and about 15,000 miles into space. Any object passing through a beam was illuminated and the reflected signals acquired by one or more or the six receiving stations along the same latitude as the transmitter stations. Unclassified and classified catalogs of all known objects in orbit were prepared from data from the Space Surveillance Fence and other sensors.

The Air Force assumed operation of the Space Surveillance Fence from the Navy in 2004. It was decommissioned in 2013, to be replaced by a space-based system.

SPX Communications manufactured the antenna. The Air Force transferred it to the Museum in 2014.

Collection Item Long Description:

Inventory Number



Country of Origin

United States of America


  • Aluminum Alloy
  • Plastic


Approximate: 44.4 × 78.7cm (1 ft. 5 1/2 in. × 2 ft. 7 in.)

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum