Topband: 160 Meter Propagation

[Robert Brown]

G'morning all,

In connection with the remarks about propagation conditions at low
latitudes like A9 nd 9V, let me point out that GEOMAGNETIC COORDINATES
instead of geographic coordinates are the important factor.  160 meter
signals are propagated through the earth's field and there is a vast
difference between signals which propagate through field lines that are
almost parallel to the earth (low magnetic latitudes) and field lines
which are more perpendicular to the earth (high magnetic latitudes).

As a result, W to E paths like 9V to the USA have a much higher
probability of being ducted (with very efficient propagation) than E to W
paths in the opposite direction.  You can think about that the next time
you call a 9V and he does not respond to your call.  It's not a matter of
attitude, just latitude, GEOMAGNETIC latitude.

73,

Bob, NM7M


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