HIAWATHA VALLEY 10-X CHAPTER
SUN. 2000 local 28.750 MHz
This month I'm going to try to give every-
one some idea of what factors effect prop-
Solar Flux: Solar Flux is the measurement
of overall solar activity at 2800 MHZ. It
is closely related to the Smoothed Mean
Zurich Sunspot Number. For example a
Solar Flux of 66, the lowest it can be,
equals zero sunspots. The highest Solar
Flux on record, 245 in 1958, equals 200
sunspots. The higher the Solar Flux, the
denser the ionospheric F-layer. This re-
sults in a higher MUF (Maximum Useable
Frequency) and better propagation on 10,
15 and 20 meters. However propagation on
the lower bands tends to suffer do to an
increase in the A-index.
A-index: The A-index is the measurement
of disturbance in the Earth's Geomagnetic
field with values of 0-400. As the values
increase, absorption increases, producing
selective fading and poor signal levels on
the lower bands. On the other hand, this
higher value will create Auroras, which
will produce, at times, great conditions
for communications on the 10-meter band,
and occasionally even into the VHF bands.
Conditions at the high end of this "open"
spectrum are best at the onset of a rise
in geomagnetic activity and as the dis-
turbance is breaking up. The A-index has
a much more pronounced effect on propagat-
ion at times of low solar activity.
November readings (daily from WWV)
Don't forget that weekly propagation con-
ditionscan be obtained from the Hiawatha
Valley 10-X Chapter.
In order to prevent interference with a
VE4 Chapter, the frequency of the Hiawatha
Valley Chapter has been changed to 28.750
MHz on the same date and time. This will
be effective Sunday January 9 local.