On October 9th 1988 at 23.10 GMT a new world distance record was
established on the 50 MHz band by the Greek experimental station SZ2DH
operated by Costas Fimerelis SV1DH and a station in Tokyo, when it was
proved that the signals had travelled a distance of 30,650 over the
South American continent. This is 15,000 kilometres more than the
short path between the two stations, over which there was absolutely
no propagation at that moment in time.
A simple 5 element Yagi and a power of 100 watts was used at
SZ2DH. The contact was on CW but the signals were so strong that it
might well have been on SSB. It is estimated that 8 hops were needed
to cover this record distance.
Most people know by now that SV1DH was one of the principal
stations involved in the very successful Transequatorial propagation
tests which took place during the 21st sunspot cycle between 1977 and
1983. Costas gave me a simplified explanation of the phenomenon first
noticed by Ray Cracknell ZE2JV and Roland Whiting 5B4WR way back in
September 1957, namely that VHF signals can travel great distances
across the equator (5,000 to 8,000 kilometres) during the years of
high sunspot activity.
Costas said that usually stations located approximately the same
distance north and south of the magnetic (not geographic) equator can
contact each other shortly after sunset at both locations. The first
such QSO took place on the 10th April 1978 between ZE2JV and 5B4WR.
Two days later ZE2JV contacted George Vernardakis SV1AB and this
contact was followed a few days later with QSOs with SV1DH and SV1CS.
(Fuller details of these contacts are given later in this book in the
interview with SV1AB).
In October 1976 there was a rumour that 145 MHz signals had been
heard directly between Argentina and Venezuela. With the imminent
beginning of sunspot cycle 21 many amateurs in the northern and
southern hemispheres began organizing tests on 50,144,220 and 432 MHz.
Within less than a year successful 2-way contact was established
between Argentina and Venezuela on 144 MHz.
Greece is favourably placed for TEP to countries in Africa where
there is considerable amateur radio activity, like Zimbabwe and the
Union of South Africa. So towards the end of 1977 SV1AB and SV1DH
began looking for colleagues in suitable geographic locations with the
appropriate equipment and the time and inclination to engage in tests
which could go on for months and months on end. Very soon the
following stations agreed to participate in the tests. The northern
group included SV1AB, SV1DH, 5B4WR and 5B4AZ. In the southern
hemisphere participants were ZE2JV (now G2AHU), ZS6PW, ZS6DN, ZS6LN
and ZS3B.
After 4 months of daily test schedules, early in 1978, successful
contacts took place on 144 MHz, some of which constituted world
distance records for that time, as can be seen in the accompanying
table. Amateurs in Malta, Italy, France and Spain soon began to
participate in the tests, as well as amateurs in other areas of South
Africa.
It can be seen from the world map that the magnetic dip (shown as
a heavy line) is very different to the geographic equator. The QTH of
SV1AB is in a suburb 10 kilometres north of SV1DH's so George's
contacts with the stations in Africa always had that edge on them.
In South Africa Dave Larson ZS6DN had set up a beacon which was
first heard in Athens by SV1AB in February 1979. Within a few days
ZS6DN had QSOs with SV1DH and SV1AB. The latter contact was a world
distance record via the F-regions of the ionosphere because of the
extra distance involved owing to the locations of the two Greek
stations, as mentioned in the previous paragraph.
For anyone who may be interested very comprehensive reports of the
work done in transequatorial propagation during cycle 21 and earlier
appeared in articles written by Ray Cracknell ZE2JV/G2AHU and Roland
Whiting 5B4WR/G3UYO in the June/July/August 1980 issues of Radio
Communuication, the journal of the R.S.G.B. and in the
November/December 1980 issues of QST.
RECORD TRANSEQUATORIAL PROPAGATION CONTACTS
DURING SUNSPOT CYLE 21