Moonbounce (EME) Planner
Moonbounce, or EME (Earth-Moon-Earth), is the ultimate ham radio challenge: you aim your antenna at the moon, your signal travels about 480,000 miles round trip, bounces off the lunar surface, and is heard by a station on the other side of the world. To make a contact, both stations need to see the moon at the same time, and conditions change every day as the moon moves closer and farther away and passes in front of noisy parts of the Milky Way. This planner works it all out from Absecon, NJ (grid FM29).
Next 7 Days: When You Can Both See the Moon
Getting Started on EME
Digital modes made EME possible for much smaller stations. With the Q65 mode in WSJT-X, a single long Yagi and a few hundred watts on 2 m can work the big EME stations, especially at moonrise and moonset when ground reflection adds a few dB of free gain. Common digital activity areas are around 50.190 MHz, 144.120 MHz, 432.065 MHz and 1296.065 MHz; check current activity before you call. Schedule contacts ahead of time on an EME chat or logger page, and always point your antenna at the moon using the azimuth and elevation shown above.
How it works: “Degradation” is how much worse conditions are than the best possible night, in dB. It adds the extra path loss when the moon is far from Earth (apogee), the extra noise when the moon sits in front of the bright Milky Way (worst on 6 m and 2 m), and a penalty when the moon is close to the sun. The polarization offset is the angle between how the two stations’ signals arrive; on 6 m, 2 m and 70 cm it can cost several dB, while on 23 cm circular polarization makes it disappear. The ionosphere also rotates polarization (Faraday rotation) in ways that cannot be predicted, so treat the numbers as a planning guide.