\n<\/p>\n
Solar activity was a bit weak during recent days. Average daily
sunspot number was 159.1. During the previous week the average was
194.7.<\/p>\n
Predicted solar flux for the near term is 165 on January 10-11, 160
on January 12, 155 on January 13-17, 200, 210 and 220 on January
18-20, then 230 on January 21-25, then 225, 220, 215, 210, 205 and
200 on January 26-31, 170 on February 1-2, 165 on February 3-4, 170
on February 5-6 and 175 on February 7.
\u00a0
Predicted planetary A index is 8 on January 10-11, then 10 on
January 12-13, 5 on January 13-14, then 8 on January 15-16, 10 on
January 17-20 and 5 on January 21-30, then 18, 15, 12, 10 and 8 on
January 31 through February 4.<\/p>\n
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s
Ionosphere – January 9, 2025, from F. K. Janda, OK1HH:<\/p>\n
“For most of the eleven-year solar cycle, two numbers are more or
less sufficient to give us a rough estimate of the state of the
ionosphere and shortwave propagation conditions: the solar activity
index (optimally the solar flux) and the geomagnetic activity index
(usually the daily A index or the three-hour K index is sufficient).
We need more information during the high solar activity period and
much more at the peak of the high cycle.<\/p>\n
“It may not yet be enough to understand what is going on, let alone
predict it. These include the solar wind speed and particle density
(free electrons and especially energetic protons) and the strength
and polarity of the longitudinal component of the interplanetary
magnetic field. Another excellent tool is ionospheric probe
measurements, especially ionograms. Unlike the pre-Internet era, we
all have access to them.<\/p>\n
“Yet, or perhaps because of this, we often experience surprises,
whether a lull or disturbance. The quiet post-Christmas period and
the big solar flares on 30 December were followed by geomagnetic
disturbances on 1-2 January, accompanied by auroras and SAR,
observable even in the mid-latitudes. The following decrease in
solar activity and irregular rises in geomagnetic activity (3-7
January) mostly resulted in a deterioration of shortwave conditions.
The improvements were mostly brief and occurred irregularly.
Moreover, forecasts of further developments were unreliable.<\/p>\n
“A further upsurge in solar activity is not expected until the
second half of January, after large sunspot groups begin to reappear
in the eastern part of solar disk. With few exceptions, major
geomagnetic disturbances should follow after the active regions on
the Sun reach the central meridian, in February.”<\/p>\n
“Solar Observances” from the Royal Observatory of Belgium:<\/p>\n
https:\/\/www.sidc.be<\/p>\n
For more information concerning shortwave radio propagation, see
and the ARRL Technical Information
Service web page at, For
an explanation of numbers used in this bulletin, see
.<\/p>\n
An archive of past propagation bulletins is at
. More good
information and tutorials on propagation are at .<\/p>\n
Also, check this article:<\/p>\n
https:\/\/bit.ly\/3Rc8Njt<\/p>\n
“Understanding Solar Indices<\/em>” from September 2002 QST<\/em>.<\/p>\n Instructions for starting or ending email subscriptions to ARRL Sunspot numbers for January 2 through 8, 2025 were 173, 190, 193, \u00a0<\/p>\n<\/p><\/div>\n
bulletins are at .<\/p>\n
178, 154, 113, and 113 with a mean of 159.1. 10.7 cm flux was 212.4,
199.9, 209.3, 168.6, 171.9, 167.7,and 160.2 with a mean of 184.3.
Planetary A index was 22, 9, 32, 20, 12, 15 and 8 with an average of
16.9. Middle latitude A Index was 14, 7, 21, 12, 13, 8, and 6, with
a mean of 11.6.<\/p>\n