Up to the end of 1988 the only Greek amateur who had positively
authenticated Moonbounce contacts was Costas Georgiou SV1OE. His very
first contact was made in 1982 when he contacted VE7BQH in Canada on 2
metres. In the ensuing four years Costas managed to work four more
stations: K1WHS, SM4GVF, W5UN and KB8RQ.
In 1982 Costas had been trying for three years, without success, to
hear his own signal via Moonbounce. The reason for his failure was
that he was unaware of a very basic fact.
"I was completely ignorant of the Doppler shift effect," Costas
told me. "The frequency of received signals varies according to the
position of the moon. If it is to the East of your own location the
signals return 500 to 1,000 Hz below the original transmitted
frequency. For years I had been sending long dashes slowly and waiting
to hear my signals return on the same spot, which they never did.
This happens for one instant only, when the Moon is at 180 degrees
azimuth, exactly due south. When it moves to the west of south the
returning frequency is correspondingly higher. Using a 50Hz audio
filter (which is essential for Moonbounce) it is very easy to miss the
weak signals. Soon after I found out my ridiculous mistake I began to
hear my signals, naturally with a delay of one or two seconds because
of the enormous distance involved--770,000 kilometres, 385,000 there
and 385,000 back.
Costas continued: "My next problem was finding the moon. I had no
computer at the time and no Keplerian elements. I mounted a small
video camera in the centre of four 16-element Yagi antennas and
rotated the elevation and azimuth motors until I could see the moon in
the centre of the monitor in the shack. Of course when the sky was
overcast I was out of business. Much later when I obtained a little
Sinclair ZX80 computer life became easier.
"When I made my first contact I was simultaneously in QSO with
SV1AB and SV1IO on 1,296 MHz who could hear what was going on. I
remember SV1AB got very excited and began shouting 'I can hear him, I
can hear him!' The QSO was with VE7BQH. Later Lionel sent me a very
valuable present, valuable not for its cost but for the fact that it
was something quite unobtainable in Greece at that time--a very
low-noise preamplifier for 2 metres.
"After the successful launch of Oscar 10 those amateurs who had
complex antenna systems and low-noise receivers they had used for
Moonbounce congregated on 145.950 and spoke to each other on QRP which
prevented ordinary mortals from hearing them. By QRP I mean outputs
of half a watt or less. But when finally one day I broke into a net
QSO I arranged schedules for Moonbounce with two stations in Sweden.
I had a successful contact with one of them but never heard the other.
The reason may have been a very simple one: the polarisation of
signals returning from the Moon varies from one moment to the other,
so if you have been transmitting with horizontal polarisation and go
over to reception it is very easy to miss the answer of the other
station if the polarisation has changed."
SV1OE then explained the very strict procedure which must be
adhered to for Moonbounce schedules.
"Schedules are arranged to last one hour. The first station to
start transmitting on the hour must be the one whose QTH lies to the
east of the other. The calling frequency for Moonbounce is 144.011
MHz., and the duration of the call is 2 minutes, but for the first
minute and a half you call CQ DE SV1OE and during the last half minute
you also give the call of the station you are trying to contact, for
instance G3FNJ DE SV1OE. You must on no account transmit for more
than two minutes because at the beginning of the third minute the
other station will begin transmitting the same pattern of signals. But
if he has heard you he will alter the pattern. For the first half
minute he will send SV1OE DE G3FNJ and for the ensuing minute and a
half he will transmit the letter O which signifies that he has heard
your callsign completely and without difficulty i.e. Q5 in the Q Code.
If I have also heard your callsign completely I will send G3FNJ for
half a minute followed by RO for a minute and a half, which means that
I have also received your callsign and your O. And you will reply RO
73 which concludes the successful contact.
"There are one or two other letters that can be used. Sending M
signifies that I hear you well but can only copy 50% of your
transmission, equivalent to Q3. And the letter T signifies I hear you
but cannot read you at all--Q1.
"It has been found by experience that the best sending speed is 8
w.p.m. Sending slowly or very fast presents problems at the other
end."