Project Moonbounce
Earth-Moon-Earth Station VA7MM

EME Frequencies    1296 MHz (23cm)

Coquitlam, British Columbia, Canada
Position 122.7600W 49.2894N
Grid Square CN89OG

Mark Mattila, VE7CMK
e-mail: ve7cmk@hotmail.com
Toby Haynes, VE7CNF
e-mail: tobyhaynes@telus.net
  


Mark Mattila VE7CMK / VA7MM                                                     Toby Haynes VE7CNF

 

Project Moonbounce is a partnership between Mark Mattila and Toby Haynes, started in the fall of 2002 to take on the technical challenge of Earth-Moon-Earth communication.  At the outset key decisions were at hand to move the project forward including the frequency band, antennas, equipment and cost.  The amateur radio community was very helpful offering advice and equipment and with the purchase of a used transceiver and power amplifier for the 23cm band the project was underway.  Acknowledgements to the amateur radio community include Val Lavender VE7VL, Cor Maas VE7BBG, Gunter Neugebauer VE7CLD, Lionel Edwards VE7BQH, Barry Malowanchuk VE4MA.  Over the period of about a year we designed, assembled and tested the components of the 1296 MHz EME station. The first signals were received from the moon during the October 2003 ARRL EME contest. On the November 2003 contest weekend we had transmit capability and made our first eleven 2-way CW EME contacts. In the January 2004 EME SSB contest we achieved a 2-way voice contact with OE9XXI in Austria and in March 2004 we completed another 17 contacts in 10 different countries during the European EME Contest. By November 2006 the station had logged 58 initial CW/ SSB mode, 16 initial digital mode and 233 total EME contacts since start up.

Amateur Radio Earth-Moon-Earth Communication

EME is the art of bouncing radio signals off the moon. Scientists and the military experimented with moonbounce in the 1950's. Radio amateurs first succeeded with EME communication in 1960. Amateur EME is easier now, using a practical blend of new and old technology based on the cumulative experience of many amateurs over the years.

Amateurs attempt EME for the technical challenge. Assembling an EME station requires attention to detail, and operating EME requires patience. The signals are weak. Messages consist mostly of station call signs and signal reports in Morse code, repeated many times so that they can be heard during a moment of good signal amidst the usual fading and noise. Extended and comfortable voice conversations off the moon are done by a few amateur stations with very large antennas and high transmit power.

G4CCH (UK) recorded our signal off the moon during the November 2003 ARRL EME contest. Here is the EME Audio, "G4CCH de VA7MM" (313K). Here is the loudest signal we've heard from the moon, W6IFE transmitting from the Owens Valley Radio Telescope in California "CQ CQ de W6IFE W6IFE" (359K). Also hear recorded audio of a signal bounced of the International Space Station later on this page.

 VA7MM 23cm EME Station


Dish from the rear showing counterweights, altitude actuator, mount, and feed.

Antenna

  

 
Equipment at the operating position, and the power amplifier.

Station Equipment

Power Amplifier

Basic Station Performance

 


Inside the antenna position controller.

 
Sheet metal and feed probe parts for our VE4MA feed antenna. Access to a friend's lathe and vertical mill (Robert Carlson) helped a lot with this project.

  
The cavity amplifier unit design is based on a military UPX-4 pulsed L-band transponder transmitter. It was first modified by hams for the 23-cm band in the early 1970's. This one was built from stock brass by Hans Lohmann Rasmussen OZ9CR. It is shown with air-cooled tubes installed (center). The 7289/3CX100A planar triode tubes (left) have been modified for water cooling (right) in our amplifier. The cavity unit, chassis, and HV power supply (a modified AM modulator from an RCAF transmitter) were originally owned by VE7VL.

 

ISS-Bounce

In a joint experiment with Cor Maas, VE7BBG (Duncan, B.C.), we used our EME stations to bounce a signal off the International Space Station on May 16, 2004, ISS Orbit 31330.

For a local high-elevation pass, both station antennas were set to auto-track along the predicted trajectory of ISS. VA7MM transmitted CW while VE7BBG listened for the signal shifted by doppler up to 60 kHz. The signal scattered off the ISS was heard for about 3 minutes.

Cor was able to hear up to a S4 on his receiver before the signal was lost. In the downloadable audio clip (below) the frequency shift in the signal is Cor's manual tuning of the signal to compensate for the changing doppler shift. The signal was lost as the ISS passed overhead and the doppler shift was too rapid to keep up with manual tuning.

Audio Recording ISS-Bounce Audio (490K)

Communicating by passive satellite-bounce requires fast and accurate antenna tracking and computer-controlled compensation for the doppler shift. VE7BBG and VA7MM are studying computer-controlled doppler compensation for future experimentation.

 


Dish and feed before installation on the tower. Jupiter is the station mascot.