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New 10-GHz Earth-Moon-Earth World Record Set


A new 10-GHz Earth-Moon-Earth (EME or moon bounce) world record has been set. On September 9, Rex Moncur, VK7MO, and Jim Malone, WA3LBI, completed a 18,949.4-kilometer contact using QRA64D. This extends by approximately 600 kilometers the previous world record of 18,337 kilometers held by DL7FJ and ZL1GSG, who used CW.

The participants said the key was to find locations with nearly 0° take-off, which essentially means across water. VK7MO operated from OF76nk at Meelup in Western Australia; WA3LBI operated from FM28io in Delaware. Both stations operated portable. Coincidentally, “Meelup” is an aboriginal word meaning “place of the rising Moon.”

VK7MO ran 50 W to a 1.13-meter dish using linear polarization. WA3LBI ran about 125 W to a 2.4-meter dish, RKI feed by Bert Moderman, circular polarization, mounted on a trailer. The loss in going from linear to circular polarization was somewhat less than the expected 3 dB, due to depolarization at the Moon surface (probably around 2 dB).

The time was chosen to maximize the Moon window when spreading was low at 34 Hz and lunar degradation low at 0.8 dB.

WA3LBI was first decoded at –23 dB at 1317 UTC when ground noise would be an issue, as the Moon was at 0° and only partially visible. His signal later peaked at –19 dB, when the elevation was around 2° at VK7MO. In addition to the basic contact requirements, some text messages celebrating the record were also exchanged.

Afterward, VK7MO worked Al Ward, W5LUA, with strong signals up to –14 dB, followed by a second contact with WA3LBI, whose signal peaked at –17 dB and dropped to –23 dB at 1353 when WA3LBI lost the Moon.