Over-the-Horizon Backscatter Radar Network, Christmas Valley Radar Site Transmit Sector Five Sounder Antennas, On unnamed road west of Lost Forest Road, Christmas Valley, Lake County, OR

Significance: The Over-the-Horizon Backscatter radar network was an important physical and scientific product of the Cold War. From theories that had been conceived in the days of early long-distance radio transmissions, and building on over three decades of research into the subject, the network was a tremendous technological and military accomplishment. Although it was only starting operation as the Cold War was ending, the ability of a radar system to warn against low-flying aircraft at distances of up to 1,800 miles away was an amazing step forward in air defense.
The two structures measure ionospheric conditions and are collocated with the transmitter arrays in each sector.
Survey number: HAER OR-154-L