Propagation to Western Europe

The following comments from Bob Brown, NM7M, are regarding propagation between Western Europe and Scarborough Reef:
Propagation on paths toward Europe-
From Scarborough Reef, paths to Western Europe go off to the west
and extend from more than 9,000 km to almost 12,000 km.  In terms
of hops, that would be 3-4 signal reflections off the ionosphere
and the paths would start at a low latitude at The Reef.  Beyond
that, the paths would cross mid-latitudes in China and Russia,
spanning a range in latitude from 40N to 60N.
The path headings would be in a small range at The Reef, from
about 315 degrees to 330 degrees east of north to cover directions
from the Mediterranean Sea to lower Scandinavia.  While a beam
antenna could include those directions with one setting, the
extent that the "footprint" of the antenna pattern could cover
that region would depend on the radiation angle at the time.  In
any event, since Western Europe could be contained in one beam
width, that means a wide range of calls/prefixes could be directed
toward The Reef at one time, making for a serious QRM problem when
a band is open.
At the time of the DXpedition, the hours of darkness across Asia
and Russia allow operation on lower frequencies, say 3.5 MHz and 7
MHz, for around 2 to 4 hours, 1900 UTC to 2100 UTC for a path to
Sweden and 1800 UTC to 2200 UTC for one to Italy.  Beyond that,
paths toward the Mediterranean would be open to higher frequencies
than those toward the Baltic.  Thus, depending on the level of
solar activity at the time, paths to Italy could be open beyond 18
MHz during times of daylight but there would be little prospect of
that being the case for a path to southern Sweden.
Operations on the lower frequencies would be best when the path is
in darkness so as to minimize D-region absorption.  But absorption
decreases at higher frequencies so operations could commence there
before sunset in Western Europe.  And since F-region critical
frequencies peak after the sun reaches its highest elevation and
then decay slowly after sunset, probably the best time for making
contact between Western Europe and The Reef on 14 MHz would be as
dusk approaches, say after 1300 UTC in Italy and after 1500 UTC in
Portugal.  There would be no real problem with D-region absorption
and the path would be open until when the critical frequency on
the first hop toward The Reef fell below 14 MHz, a few hours
Again, consult a propagation program for details that would apply
to any specific location or band.  The paths from The Reef to
Western Europe do not extend into high latitudes and propagation
should be well described by MINIPROP PLUS or Capman and paths
shown clearly by DXAID.

For everything you need to know about basic HF radio propagation, you should pick up a copy of Bob's book, The Little Pistol's Guide to HF Propagation. It's available for $10 (plus $2 S&H) from Worldradio Books, P.O. Box 189490, Sacramento CA 95818, U.S.A. Or, for on-line information regarding radio propagation, check out the propagation links on the N4GN Home Page.
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Last modified 02 February 1999 by Tim Totten,