Active EME experiments, station setups, operating guides, and the full history of Earth–Moon–Earth radio communication.
From Cold War experiments to modern amateur radio — the remarkable story of bouncing signals off the Moon.
On January 10, 1946, the U.S. Army Signal Corps achieved the first successful Earth–Moon–Earth radar contact at Fort Monmouth, New Jersey. A 111.5 MHz signal was transmitted toward the Moon and its echo was detected 2.5 seconds later — the first human signal to reach another celestial body and return.
The U.S. Navy developed the MOON RELAY communication system, establishing a secure over-the-horizon link between Washington, D.C. and Hawaii. These military systems used high-power transmitters and large dish antennas to maintain communication links immune to ionospheric disruption and nuclear EMP — a key Cold War advantage.
Ross Bateman (W4AO) and Bill Smith (W3GKP) made the first amateur EME QSO on 144 MHz in January 1953. This proved that moonbounce wasn't exclusively the domain of governments — amateur operators with determination and skill could work Earth–Moon–Earth on a budget.
Several nations operated moonbounce communication networks. The Soviet Union's Zoloto ("Gold") system and US COMSEC systems used EME as a secure, unjammable strategic communication channel. The Moon acted as a 384,400 km passive reflector with no active electronics to jam or destroy.
The 1970s saw dramatic expansion of amateur EME onto 432 MHz and 1296 MHz. Groups such as the Rhododendron Swamp VHF Society organized coordinated moonbounce contests. Teams built large Yagi arrays — 32 or even 64 elements — to achieve the gain needed to detect the Moon's extremely faint reflected signals.
Joe Taylor (K1JT), Nobel laureate in physics, released WSJT software introducing the JT65 mode. Designed specifically for EME, JT65 could decode signals 10–15 dB below what the human ear could detect. This single advance democratized EME — suddenly stations with a single Yagi and modest power could work moonbounce reliably.
Q65 mode, an evolution of JT65 optimized for Doppler-spread paths and millimeter-wave EME, pushed sensitivity even further. Today EME is active on frequencies from 50 MHz to 122 GHz, with a global community of thousands of operators using SDR receivers and automated scheduling via platforms like ON4KST chat.
Modern EME spans 50 MHz to 122 GHz. Single-dish stations with 3 m dishes routinely complete contacts on 10 GHz. The ARRL EME Contest attracts hundreds of stations across all continents, and DXCC via EME — working 100+ countries via the Moon — is now an achievable goal for serious operators.
Active projects, documented experiments, and reproducible setups for moonbounce communication across VHF, UHF, and microwave bands.