[5] It was designated a National Historic Landmark in 1989 because of its association with the research work of two radio astronomers, Arno Penzias and Robert Wilson.

This helped change the science of cosmology, the study of the universe's history, from a field for unlimited theoretical speculation into a discipline of direct observation.

[7] The horn antenna at Bell Telephone Laboratories in Holmdel, New Jersey, was constructed on Crawford Hill in 1959 to support Project Echo, the National Aeronautics and Space Administration's passive communications satellites,[8][5] which used large aluminized plastic balloons (satellite balloon) as reflectors to bounce radio signals from one point on the Earth to another.

The antenna's elevation wheel, which surrounds the midsection of the horn, is 30 feet (9.1 m) in diameter and supports the structure's weight using rollers mounted on a base frame.

The ability to locate receiver equipment at the horn apex, thus eliminating the noise contribution of a connecting line, is an important feature of the antenna.

[10] When not in use, the turntable azimuth sprocket drive is disengaged, allowing the structure to "weathervane" and seek a position of minimum wind resistance.

[5] A plastic clapboarded utility shed 10 by 20 feet (3.0 by 6.1 m) with two windows, a double door, and a sheet-metal roof, is located on the ground next to the antenna.

It is extremely broad-band, has calculable aperture efficiency, and the walls of the horn shield it from radiation coming from angles outside the main beam axis.

Advocates felt that a better fate than the horn antenna or its site encountering destruction to make way for a planned real estate development.