October 1960 Electronics World
Wax nostalgic about and learn from the history of early electronics. See articles
Electronics World, published May 1959
- December 1971. All copyrights hereby acknowledged.
We are nine days away from the 54th anniversary of the first
successful earth-moon-earth (EME) communication path by amateur
radio operators. What is today a routine operation by Hams was
a big deal back in the day. The moon was still a mystery to
most of the world since at the time not even an unmanned probe
had been sent for exploration. 1,296 MHz was the frequency
of choice using a 1 kW klystron on the transmit end and
a highly sensitive parametric amplifier on the receive end,
with high gain parabolic antennas on both ends. The Federal
Communications Commission (FCC)
has allocated the 144.00-144.20 MHz
(2 m), 222.0-222.025 MHz
(1.25 m) 432.00-432.07 MHz
and (70 cm), 902.8-903.0 MHz,
(33 cm), 1295.8-1296.05 MHz
(23 cm), and 2303.9-2304.2 MHz
bands for various modes of EME operation per
Ham Radio Earth-Moon-Earth Contact
Details on the first amateur radio moon-bounce two-way microwave
contact between California and Massachusetts.
The first amateur radio moon-bounce two-way microwave communication
took place on Sunday, July 17 between two distant points. This
contact marks an important milestone in the development of amateur
radio. The historic contact was between the members of the Eimac
Radio Club in San Carlos, California and Mr. Sam Harris, Rhododendron
Swamp VHF Society in Medfield, Mass.
Some members of the Eimac Radio Club in San
Carlos, California, who participated in the moon-bounce circuit
are shown here with their make-shift parabolic dish.
After months of personal effort by the radio amateurs concerned
with this project, signals were transmitted in both directions
on 1296 mc. The equipment was then refined and the first successful
two-way communication was made. The first transmission was from
West (W6HB) to East (W1BU). The pattern was then reversed and
the first amateur coast-to-coast communication via the moon
completed. At each end of the circuit, a 1000-watt klystron
was used in the transmitter and a very sensitive parametric
amplifier in the receiver.
Path of the 1296-mc. microwave signals.
This successful reception and transmission using the moon
as a signal reflector will stimulate efforts to improve amateur-built
equipment for further moon-bounce communications. The only other
moon-bounce communications equipment in existence is military
or experimental in nature; the principal installation is the
Naval link between Washington and Hawaii.
Members of the Eimac Radio Club who participated in the moon-bounce
circuit are: Bill Orr, W6SAI; Hank Brown, W6HB; Bill Eitel,
W6UF; Ray Rinaudo, W6KEV; Bob Morwood, K6GJF; Bob Sutherland,
W6UOV; Hugh MacDonald, W6CDT; George Badger, W6RXW; Allan Beer,
K6GSO; Al Clark, W6MUC; Mike Krivohlavek, K6AXN, and Charlie
Posted July 9, 2014