Satgen 219  RS12 DX and Transpolar 10m     by GM4IHJ          5th June 93
BID of this msg is SGEN219  Please use that BID if you retransmit this msg

After 50 years in the radio business, there is a tendency to believe that
you have seen it all. It is therefore a considerable surprise when new
things keep turning up. Time was when Propagation Wisdom said - 10m only
present during the day, in winter, over non polar routes , at solar cycle
maximum. But the last couple of years of RS12 operation has kicked these
"rules" , right out of the window.

The last few weeks of May have been the best for RS12 ( 21 MHz up 29 MHz
down ) DX for some time. Having monitored transpolar 29 MHz traffic over
the winter months, the expectation was that NM7M's Polar Plasma
Propagation mode , where a southerly interplanetary magnetic field allows
Solar Wind plasma to get into sub polar and polar regions, would disappear
as we got into spring and summer. Theory was that as the Sun began to
illuminate the Arctic Ionosphere once more, the ionisation of the D and E
layers would produce too much absorption , and signals to and from
satellites or terrestrial stations would be blocked on transpolar routes.

This has not happened. After a tremendous early spring burst in late
February early March, April and early May were almost dead - as expected.
But since 26th May there has been an almost continuous series of 10m
satellite signals to and from UK - Japan and the Russian Far east between
1700 and 2000ut.

Clearly this transpolar propagation takes some explaining. But at least it
has happened before in May 92, when dare I say it, one or two folks said
it was a fluke. But what is somewhat more startling is that the
propagation seems to be extending to a GM to VE7 path, with RS12 being
tracked down into Canada over Fort Simpson and on towards Edmonton and
Calgary at about 1900 ut. In both cases UK - Japan + Russian Far East, and
UK Western Canada it is going to be difficult to determine the signal
paths to UK ,because the signal doppler shift is often abnormal indicating
a non great circle path. Indeed the UK - Canada path is apparently not the
short route ( UK - N Greenland - W Canada), but appears to have a north
easterly azimuth from UK suggesting that it is a non great circle route
east over Siberia - Bering Straits - W Canada ). Lets hope these incidents
continue so that we can have some fun sorting out this puzzle.

Meanwhile for RS12 DXers . Mary Lou Brown NM7N will be with a team of YL
DXers at FP the French Island of St Pierre near Newfoundland 17th to 24th
June 93 operating all RS12 orbits which have mutual windows with Europe.
So please give the ladies a call, for an unusual location which should be
in range of almost all Europe and some of North Africa. The team go on to
Sept Isles VE2 25 to 30 June. 73 de GM4IHJ @ GB7SAN