EME – What’s that?

The technical and operating challenge!


Earth-Moon-Earth communication, also known as “moonbounce” is (was?) one of the most fascinatig parts of our hobby. The concept is simple: the moon is used as a passive reflector for VHF, UHF and SHF signals. With a total path length of about 800.000 km EME is the ultimate DX.

EME activity was (is?) primarily a CW mode. However, improvements in station equipment now allow the best-equipped stations to make SSB contacts under the right conditions.

Regardless of the transmission mode successful CW – EME operating requires…

  • Power output as close to the legal limit as possible.
  • A good-sized antenna array. Arrays of 4, 8 or even more Yagis are common as well as large parabolic dish antennas
  • Accurate azimuth and elevation tracking
  • Minimal transmission line losses
  • The best possible receiving equipment, generally a receiver with a low system noise figure and a low-noise preamplifier mounted at the antenna
  • And finally very good ears… (when talking about CW-EME)

Nowadays, with digital modes like JT65, mostly everyone with a 100 W station and a single yagi antenna are able to complete successful EME contacts on 2m and 70cm with one of the “big guns”.