09/12/2025

Solar activity has been at very low to low levels this past week.
 
Low level C-class flaring was observed from Regions AR4210 and
AR4207. Slight growth was observed in Regions AR4213 and AR4214. The rest of the spotted regions were either stable or in decay. Solar
activity is expected to remain at low levels, with a chance for
isolated M-class flares (R1-R2/minor-moderate) through September 13.
 
A CME (Coronal Mass Ejection) was observed just beyond the Western
limb on September 9. No impacts are expected, and no Earth-directed
CMEs were observed.
 
Solar wind parameters continued to be enhanced under positive
polarity coronal hole high speed stream (CH HSS) influences. Solar
wind speed increased from approximately 450 km/s to near 550 km/s.
Elevated solar wind conditions are expected to continue into
September 12.  Another enhancement is likely on September 14 with
the onset of negative polarity CH HSS influences and the possible
glancing effects of the September 11 CME.
 
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, September 11, 2025, by F. K. Janda, OK1HH:

"During a seven-day interval (August 26 to September 1), when solar
flux values were above 200 s.f.u., there was a decline to below 120
s.f.u. during the first ten days of September. Which also occurred
during the previous solar rotation - on August 17-19.

"Solar flare activity simultaneously decreased significantly, while
all sunspot groups moved to the western half of the solar disk.
Instead, we are now observing a large coronal hole, located mostly
north of the solar equator, whose boundary has already crossed the
central meridian.

"The intensified solar wind, which is definitely blowing from its
western edge, is expected to reach Earth since September 13. It will
likely contribute to increased geomagnetic activity, which, combined
with relatively low solar activity, will have negative consequences
for the state of the ionosphere. MUF values will decrease,
attenuation will increase, and shortwave propagation conditions will deteriorate.

"Starting in the half of September, however, solar activity will
begin to increase, although not as significantly as it did in
August. In addition, geomagnetic activity appears to be declining at
the same time. The approaching Autumn Equinox will also have a
significant impact on the state of the ionosphere. These are already
three reasons why shortwave propagation conditions should gradually
improve."

The Predicted Planetary A Index for September 13 to 19 is 5, 12, 20,
15, 8, 8, and 8, with a mean of 10.9.  Predicted Planetary K Index
is 2, 4, 5, 4, 3, 3, and 3, with a mean of 3.4.  10.7 centimeter
flux is 120, 125, 130, 135, 135, 140, and 145, with a mean of 132.9.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.

 


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

09/19/2025

Solar activity was at low levels this past week. Low-level C-class
flaring was observed from Regions AR4216 and AR4217, as well as from
Region AR4213 just beyond the Southwest limb. Slight growth was
observed in all spotted regions. No Earth-directed CMEs were
observed. Solar activity is expected to be low, with a chance for an
isolated M-flare (R1-R2/minor-moderate), through September 20.
 
Solar wind parameters were indicative of coronal hole high speed
stream (CH HSS) influences. Solar wind speed increased to near 760
km/s early on September 15 before subsiding to between 600-700 km/s.
Solar wind parameters are expected to continue under the influence
of a negative polarity Coronal Hole High Speed Stream.  Solar wind
speed is likely to gradually diminish on September 20.  The
geomagnetic field is expected to be at quiet levels on September 20,
and quiet to active on September 21.

Spaceweather.com[1] for September 19 reports that a co-rotating
interaction region, or CIR, could hit Earth on September 22.
 
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, September 18, 2025, by F. K. Janda, OK1HH:

"The development of phenomena on the Sun and subsequently in the
Earth's magnetosphere and ionosphere during the second decade of
October was interesting and exciting. First, solar activity passed
through a 27-day minimum on October 10-13, and the subsequent
increase is likely to continue for most of the month. Above all,
however, we observed a large butterfly-shaped coronal hole on the
Sun. Predictions of when the intensified solar wind from its edges
would reach Earth rarely coincided on Sunday, September 14.

"And so, it happened after 1600 UTC. The CME of September 11 (1030
UTC) contributed to the intensification of the solar wind, while the 'Russell-McPherron effect,' which connects the Sun's magnetic field
with the Earth's magnetic field during the weeks around the equinox, contributed to the impact. During the evening, the positive phase of
the disturbance continued with an increase in the MUF of the F2
ionospheric layer.

"The geomagnetic disturbance intensified to G3 on September 15,
while on September 15-16, we experienced its negative phase with a
significant decrease in MUF in the middle and higher latitudes of
the globe. And, of course, the overall deterioration in shortwave
propagation conditions was unmistakable. The improvement began
slowly on September 17 and will continue, as we expect further
growth in solar activity for most of September. As usual, the fact
that we are in the period around the Autumnal Equinox will also
contribute to the improvement.

"We could also tell that Summer in the ionosphere was over by the
significant decrease in the activity of the sporadic-E layer, which
was still quite frequent in mid-latitudes in the first half of
September."

The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=xzoxXGTDLyM[2] .

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
tutorials on propagation can be found at, http://k9la.us/[6] .

Also, check this:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for September 20 to 26 is 5, 5, 5,
5, 5, 5, and 5, with a mean of 5.  Predicted Planetary K Index is 2,
2, 2, 2, 2, 2, and 2, with a mean of 2.  10.7 centimeter flux 135,
135, 135, 130, 125, 130, and 125, with a mean of 130.7.

 


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=xzoxXGTDLyM
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

09/26/2025

Solar activity reached moderate levels this past week. An impulsive
M1.0 flare was observed on September 24 from Region AR4217. Slight
growth was observed in Region AR4226 with an increase in spots near
the leader. New Regions AR4229 and AR4230 were numbered this period.
All other regions were either stable or in decay. No Earth-directed
CMEs were observed. Solar activity is expected to return to low
activity.

Solar wind parameters were indicative of the arrival of a negative
polarity Coronal Hole High Speed Stream (CH HSS). Solar wind speed
increased from approximately 310 km/s to near 530 km/s. Total field
showed an increase beginning on September 22. The CH HSS influence
persisted through September 23 and diminished to background levels
on September 25. A trend towards nominal solar wind conditions is
expected through September 26 as Earth moves out of a geoeffective
position with the CH HSS.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, September 25, 2025, by F. K. Janda, OK1HH:

"A study published on September 8 in the Astrophysical Journal
Letters states that solar activity will increase after approximately
sixty years of decline (following the high Solar Cycle No. 19). The
next solar cycles should be even higher than the current one and, in particular, higher than the previous one (i.e., than Solar Cycles 24
and 25).

"Short-term developments in the second half of September are in line
with forecasts. Overall solar activity has increased, although
eruptive activity is slightly lower than expected. In line with the
forecast, on September 21, the Earth's magnetic field entered the
common rotation interaction (CIR) region and the solar wind
intensified. After a two-day increase that began on September 24,
geomagnetic field activity declined again. Although the forecasts
are based primarily on the expected increase in the speed of the
solar wind flowing from the edges of coronal holes, while should
therefore be less accurate than forecasts based on observed
eruptions and CMEs, they are still relatively reliable.

"Most sunspot groups are now on the solar disk (the visible part of
the Sun), but they will gradually begin to set. Solar activity
should therefore decline by the end of September, with the decline
likely to stop in mid-October. In the Earth's ionosphere, the
decline in maximum usable frequencies (MUF) will begin with a slight
delay, similar to the expected rise in the second half of the
month."

There is a chance for isolated R1-R2 (Minor-Moderate) radio
blackouts until September 28. Unsettled to active levels are likely
on September 29 and 30, October 3 to 7, October 11 to 13, and on
October 18 due to recurrent CH HSS influences. Quiet to unsettled
levels are likely for the remaining days in this outlook period.

The geomagnetic field is expected to be quiet to unsettled levels on
September 27, and quiet to active levels on September 28.

The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=xzoxXGTDLyM[1] .

The Predicted Planetary A Index for September 27 to October 3 is 5,
5, 15, 8, 5, 5, 5, and 15, with a mean of 8.3.  Predicted Planetary
K Index is 2, 2, 5, 3, 2, 2, and 5, with a mean of 3.  10.7
centimeter flux is 175, 170, 170, 170, 160, 150, and 140, with a
mean of 162.1.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and
tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check this:

https://bit.ly/3Rc8Njt[6]

"Understanding Solar Indices" from September 2002 QST.

 


[1] https://www.youtube.com/watch?v=xzoxXGTDLyM
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

10/03/2025

Solar activity, which has been at low levels, has returned to
moderate levels. Region AR4232 produced the largest event of the
period, an impulsive M3.6 flare (R1-minor) on October 1, 2025.

An associated Coronal Mass Ejection (CME) was observed in subsequent
SOHO LASCO/C2 coronagraph imagery that began on September 29.
Analysis and modelling of the ejecta is ongoing.

Newly numbered Region AR4237 remained relatively quiet as it
developed. Region AR4263 also produced an R1 event with an M1.0/Sf
flare near the end of the reporting period.
 
It is important to note that, after careful assessment of recent
magnetograph imagery, a spot previously associated to region AR4239
is now considered part of the AR4230, explaining its reported size
increase. A new region appeared but remained unnumbered until
further observation.
 
With multiple regions continuing to exhibit growth, flare activity
is likely to remain at moderate levels (R1-R2/minor-moderate) with a
slight chance for an X-class flare (R3-strong) through October 30.
 
Weak enhancements in the solar wind environment, that began
September 29, are likely to continue as influence from a negative
polarity Coronal Hole High Speed Stream (CH HSS) persists.

The CH HSS influences on the solar wind conditions near Earth are
expected to persist through October 5, as the planet continues to be
embedded at the CH associated co-rotating interactive region (CIR).
A recurrent negative CH was observed rotating into the East limb of
the visible solar disk during the period, but no impact is expected
from it in the upcoming days.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, October 2, 2025, by F. K. Janda, OK1HH:

"During September, a relatively large number of sunspot groups were
observed on the solar disk, but there were almost no energetically
significant eruptions. It seemed to be the calm before the storm.
The question was what would cause the storm and how the disturbance
would develop. Important factors were: the proximity of the Autumn
Equinox and the configuration of areas on the solar disk.

"The following phenomena were key to further developments:
- The Russell-McPherron effect, in which the magnetic field lines of
  the Sun and Earth can connect around the equinox.
- The source of the intensified solar wind heading towards Earth.

"The second condition was also met - we observed coronal holes No.
83 and 84 on the solar disk near active regions No. 4230 and 4238,
with the space between them being close enough to the central
meridian.

"The disturbance began with a so-called positive phase on the
afternoon of September 29 UTC, while the critical frequencies in the
F2 ionospheric layer initially rose for several hours. In the
following days, the solar wind speed gradually increased to an
impressive 800 km/s. The intensity of the geomagnetic disturbance
reached grade G3 (three-hour K indices rose to 6 to 7).

"The return of the ionosphere to normal conditions will be slow, as
solar activity is expected to gradually decline in the first half of
October. In addition, after a slight lull, another disturbance can
be expected around October 7, and even after that, the situation
will not be very calm."

The latest report from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at:  https://www.youtube.com/watch?v=a7mWOPWe0NA[1] .

The NOAA Space Weather Prediction Center has a webpage that
discusses the current solar cycle progression: https://www.swpc.noaa.gov/products/solar-cycle-progression[2] .

The Predicted Planetary A Index for October 4 to 10 is 8, 8, 8, 5,
5, 5, and 5, with a mean of 6.3.  The Predicted Planetary K Index is
3, 3, 3, 2, 2, 2, and 2, with a mean of 2.4.  10.7 centimeter flux
is 170, 165, 165, 165, 155, 155, and 155, with a mean of 161.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
tutorials on propagation can be found at, http://k9la.us/[6] .

Also, check this:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

 


[1] https://www.youtube.com/watch?v=a7mWOPWe0NA
[2] https://www.swpc.noaa.gov/products/solar-cycle-progression
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

10/10/2025

Solar activity has been at moderate levels for the past 24 hours. Solar activity is expected to be low with a chance for M class flares. Solar wind speed reached a peak of 1124 km/s.

Solar activity reached moderate levels following an M2.0 flare (R1-Minor) at from a region just around the Northwestern limb. Only low-level C-class activity was observed from the remaining spotted regions on the visible disk. New Regions 4248 and 4249 were numbered as they emerged late in the period, but were otherwise unremarkable.

A chance for R1-R2 (Minor-Moderate) radio blackouts exists over October 10 to 12 due
to flare potential from several active regions returning from the Suns far side.

Spaceweather.com[1] reports on October 10, a hole has opened in the sun's atmosphere, and it is venting a stream of solar wind directly toward Earth

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere - October 10,2025

Solar activity has been declining since the beginning of October, as expected. The last slightly larger sunspot group, designated as active region AR 4236, disappeared behind the northwestern limb of the solar disk in the middle of the present week. Almost immediately after it became invisible to us, a moderately strong eruption occurred. This happened on Thursday, October 9, peaking at 12:31 UTC. However, the decline in solar activity will continue, followed by an increase that should last for almost the entire second half of October.

This will include a positive effect on the state of the F2 ionospheric layer. Although this did not bring such good conditions for shortwave propagation, precisely because of the decline in solar radiation, there were interesting improvements here and there - especially at the beginning of geomagnetic disturbances, most recently on the afternoon of October 7. However, another phenomenon played a major role in the surprising improvement in shortwave propagation conditions between Europe and the Antipodes on October 8 - the rare and rather unusual occurrence of a sporadic E layer at this time of year...

Official forecasts of increased solar activity for the second half of October are rather skeptical for the time being. This is probably because the activity on the far side of the Sun, as measured by helioseismological methods, is not high. However, this may change. A surprise in the form of faster growth cannot be ruled out.

The latest report from Dr. Tamitha Skov, WX6SWW, can be found on Youtube.

The predicted Planetary A Index for October 11 to 17 is 15, 12, 10, 8, 5, 5, and 5 with a mean of 8.5. The Predicted Planetary K Index is 5, 4, 3, 3, 2, 2 and 2 with a mean of 3. Predicted 10.7 centimeter flux is 140, 135, 135, 140, 135, 140 and 145 with a mean of 137.1.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and
tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check this:

https://bit.ly/3Rc8Njt[6]

"Understanding Solar Indices" from September 2002 QST.
 


[1] http://Spaceweather.com
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

10/17/2025

Region AR4246 underwent significant evolution, growing in overall
size while gaining multiple new spots. Subsequently, AR4246 was the
main provider of activity which included an M1.2 flare on October
13. Several coronal mass ejections (CMEs) with potential
Earth-directed components are in the mix at this time.

Additional modeling efforts are underway to perhaps confirm those
suspicions. The largest flare was a long-duration M4.8/2n on October
15. Modeling efforts showed the ejecta to be on a northward
trajectory and not on an Earthward course.
 
Other notable activity included a prominence eruption off the ENE
limb-first visible in LASCO C2 imagery on October 14. Given the
location of the event, initial analysis suggests this ejecta to be
well into foul-ball territory and not Earth-directed. Additional
modeling efforts are underway to perhaps confirm this suspicion.
 
Slight decay was observed in the intermediate portion of Region
AR4248 as it grew in length. Region AR4247 was in decay as well. The
remaining regions were unremarkable in comparison. No new regions
were assigned numbers this period. Minor to moderate (R1-R2) radio
blackouts are likely for the next 3 days, with a slight chance for
an isolated R3 (strong) event, due to the current and potential
flare activity of Regions AR4246 and AR4248.
 
Solar wind parameters continued to reflect the influence of a
negative polarity coronal hole high speed stream (CH HSS). Solar
wind speeds finally dipped below 600 km/s and phi was predominantly
in the negative solar sector.
 
Solar wind parameters are expected to continue at enhanced levels,
although gradually waning, and continuing through October 17, due to
CME arrivals from the October 11 to 13 timeframe originating from
AR4246.  Solar activity reached moderate levels due to M-class flare
activity.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, October 16, 2025, by F. K. Janda, OK1HH:

"In line with forecasts, solar activity continued to gradually
increase, including several moderately strong flares. These were
mostly observed in the active region NOAA 4246, located in the
northwest of the solar disk, while approaching its limb.

"The second of the two larger active regions is NOAA 4248, also
located in the northwest, but closer to the central meridian and the
solar equator, while relatively close to the extensive coronal hole
No. 87. In the coming days, AR NOAA 4248 will move into the active
longitudes. Therefore, its eruptive activity will increase. Between
it and the aforementioned coronal hole, a source of intensified
solar wind will form, which will hit Earth during the coming week.

"Even earlier, on October 16, when this text is being written, we
expect a G2 geomagnetic disturbance, which will first cause a brief
improvement and then a deterioration in ionospheric propagation of
short waves, which have been rather average so far. The exception
was a shorter increase in MUF on October 15 between 1000 and 1200
UTC, probably caused by an intensification of the solar wind.

"Solar activity should remain at current levels for the rest of the
month. Fluctuations in propagation conditions, mostly around average
with occasional deterioration, will depend on the irregular
occurrence of geomagnetic disturbances."
 
The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at:  https://www.youtube.com/watch?v=pAZtua4DZUs[1] .
 
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and
tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check this:

https://bit.ly/3Rc8Njt[6]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for October 18 to 24 is 5, 5, 15,
10, 8, 5, and 5, with a mean of 7.6.  Predicted Planetary K Index is
2, 2, 5, 3, 3, 2, and 2, with a mean of 2.7.  10.7-centimeter flux
is 150, 150, 150, 150, 145, 140, and 145, with a mean of 147.1.
 


[1] https://www.youtube.com/watch?v=pAZtua4DZUs
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

10/31/2025

Solar activity has decreased to very low levels. Region 4266
exhibited signs of slight development as it gained asymmetric
penumbra surrounding its trailing spots. Meanwhile, Region 4267
underwent decay, losing several leading spots. Additional activity
included a coronal mass ejection (CME) off the NE limb on October
29.
 
An associated Type II radio sweep was reported with the CME; however
SUVI 195 imagery revealed the CME to have originated on the far
side. Also, an approximate 12 degree filament eruption, centered
near N27W24 was observed becoming unstable beginning October 29.
Most of the material of this event appeared to have been reabsorbed
with perhaps a faint and narrow CME escaping. Modeling of this event
revealed a possible glancing blow to the north of Earth by late on
November 2, but confidence is low in both the analysis of this event
and the modeling outcome.
 
Solar wind parameters continued to reflect positive polarity coronal
hole high speed stream (CH HSS) influences. Solar wind parameters
are expected to continue to reflect positive CH HSS influences
through November 1.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, October 30, 2025, by F. K. Janda, OK1HH:

"It is very rare for the situation on the Sun and between it and
Earth to be as relatively simple and clear as it has been in recent
days. This is one of the reasons why it was possible to make a
fairly accurate prediction of further developments. Although there
were concerns that an intensified solar wind could hit Earth as
early as October 26, the original forecast ultimately proved
accurate and the disturbance began on October 28. The last weekend
in October was thus marked by relatively good conditions for radio
wave propagation on all shortwave bands.

"Regular helioseismological observations of the far side of the Sun
are closely monitoring the only two currently active regions on the
Sun. They will begin to emerge on the eastern edge of the solar disk
in the first half of next week, which will immediately be reflected
in an increase in solar flux. This may peak around October 10, but
it seems that it will happen sooner.

"The increase in solar activity during the usual favorable seasonal
changes alone will result in improved conditions for shortwave
propagation. With a little luck, the improvement could peak around
November 8, when the next increase in geomagnetic activity can be
expected."

Solar activity is expected to be at moderate levels until November
15 due to the return of Region 4246. Low levels are expected to
prevail from November 14 to 22 as multiple regions depart the
visible disk.

A greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels until November 15 due to responses
from recurrent CH HSS influences.  Moderate levels are expected from
November 16 to 22.

Geomagnetic field activity is expected to be at quiet to unsettled
levels on November 1 to 6, 10 to 14, and November 16 to 22.  Active
conditions are expected from November 7 to 9, and November 15.

The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=y8uEPcivbQ8[1] .

Spaceweather.com[2] for October 31 reports on "Halloween Fireballs" and
the rapid brightening of Comet 3I/ATLAS.

The Predicted Planetary A Index for November 1 to 7 is 8, 5, 5, 5,
5, 5, 8, and 12, with a mean of 6.9.  Predicted Planetary K Index is
3, 2, 2, 2, 2, 3, and 4, with a mean of 2.6.  10.7-centimeter flux
is 130, 130, 135, 140, 140, 140, and 140, with a mean of 136.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
tutorials on propagation can be found at, http://k9la.us/[6] .

Also, check this:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

 


[1] https://www.youtube.com/watch?v=y8uEPcivbQ8
[2] http://Spaceweather.com
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

10/24/2025

Solar activity reached moderate levels this past week, but has now
returned to, and remains at, lower levels. Region 4248 produced an
M1.1 flare on October 20, which was the largest event of the period.
Region 4261 was numbered this period as it rotated into better
viewing conditions.

Region 4262 was numbered this period as well, splitting it from
Region 4257. Additionally, new spots were noted near N08W00 and
N09E67 but went unnumbered due to a lack of flaring and time of
emergence. No Earth-directed CMEs were observed in available
coronagraph imagery. Solar activity is expected to remain low, with
a chance for isolated M-class flares (R1-R2/minor-moderate).
 
Additional notable activity included a type II radio sweep with an
estimated speed of 2,474 km/s and a type IV radio sweep that began
on October 21. Significant field line movement, appearing to
originate from beyond the northwestern limb, was observed in GOES
SUVI imagery beginning on October 21.  The subsequent coronal mass
ejection (CME) was then first seen on LASCO C2 coronagraph imagery
on October 21. This event has been analyzed as a far-sided
asymmetric halo.
 
Solar wind parameters were mildly enhanced this period due to
negative polarity coronal hole high speed stream (CH HSS)
influences. Solar wind speeds exhibited a decreasing trend from
approximately 600 km/s to under 500 km/s by the period's end. Phi
was predominantly positive while undertaking brief excursions into
the positive solar sector. Mildly enhanced solar wind conditions and
waning negative polarity CH HSS influences were expected to
continue.

Solar activity is expected to be at moderate levels from October 31
to November 15 due to the return of Region 4246. Low levels are
expected to prevail to October 30, and then on November 14 and 15.
Geomagnetic field activity is expected to reach G1-G2
(Minor-Moderate) storm levels on October 28 to 30.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, October 23, 2025, by F. K. Janda, OK1HH:

"Although it may not seem so at first glance, solar activity is
still at the peak of its 25th cycle. Although the number of sunspot
groups fell to six in mid-October, a week later it had risen to ten.
Few eruptions were observed on the solar disk, or the side of the
Sun facing Earth, including only a few that could be classified as
moderately strong based on the intensity of X-ray emissions.

"However, something is brewing on the far side of the Sun. This is
evidenced by the occurrence of three CMEs, the first on October 21
and the other two on October 22. The increased concentration of
protons with an energy of 10 MeV (and a lower concentration of 100
MeV) in the solar wind confirms that this is significant activity.
To analyze the development of the relevant activity, we will have to
wait until it appears on the eastern limb of the solar disk.

"The geomagnetic field has calmed down in recent days. The next
disturbance is expected around October 28. At first glance, this is
very good news for shortwave propagation conditions during the
weekend of October 25-26, but if geomagnetic activity increases
during these days, it will come as no surprise.

"In fact, with the right timing of the disturbance, it could be
followed by an increase in MUF and an overall improvement. Although
a significant deterioration in propagation conditions is expected
with a relatively high probability only after the aforementioned
disturbance (i.e., around October 29), it may occur earlier."

The Predicted Planetary A Index for October 25 to 31 is 10, 5, 5,
25, 35, 25, and 15, with a mean of 17.1.  Predicted Planetary K
Index is 3, 2, 2, 5, 6, 5, and 4, with a mean of 3.9.  10.7-centimeter flux is 150, 150, 150, 145, 145, 145, and 140, with a mean of 146.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.

 


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

11/14/2025

There were two nights of visible aurora throughout the continental
US and dead HF bands due to a severe geomagnetic storm caused by
what Space.com[1] calls "a colossal X5.1 class solar flare" and
associated coronal mass ejection (CME) on Tuesday, November 11.

Spaceweather.com[2] for November 14 reports that a NASA model of the
latest CME suggests that it could deliver a glancing blow to our
planet's magnetic field late on November 16.
 
Meanwhile, Region 4274 was responsible for multiple low- to
mid-level C-class flares. The largest was a C4.5/Sf on November 12.
Slight decay was observed in Region 4274. Motion along the inversion
lines was minimal within the group. The rest of the spot groups were
either stable or in decay. No Earth-directed CMEs were observed.
 
Solar activity is now forecast to be high, with R1-R2
(Minor-Moderate) expected and X-class (R3-strong) activity likely on
November 15, mostly due to the flare potential of Region 4274.
 
Solar wind parameters continued to reflect persistent negative
polarity coronal hole high speed stream influences (CH HSS).  Solar
wind speeds were between 450 km/s and 600 km/s. Phi was variable
through the first half of the period before turning mostly negative
for the second half. The solar wind environment had likely become
mildly enhanced with CME influences on November 10 as the November 7
CME passed in close proximity to Earth. Stronger solar wind
disturbances were likely over November 11-12 due to the anticipated
arrival of the November 9 asymmetric halo CME.

R1-R2 (Minor-Moderate) radio blackouts are likely, with a chance for
an isolated R3 (Strong) event, through 16 November primarily due to
AR4274s past flare history coupled with its current potential.

The geomagnetic field is expected to be quiet to unsettled levels on
November 15.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, November 13, 2025, by F. K. Janda, OK1HH:

"In October, during the last solar rotation, two active regions on
the Sun: AR4246 and AR4248 were very interesting. Although they were
not the largest, their magnetic configuration indicated a possible
further increase in eruptive activity. This was confirmed during the
following parade on the far side of the Sun, when we could observe
several more powerful CMEs, especially on the eastern limb of the
solar disk.

"After their emergence on the disk, the culprit was reliably
identified as the AR4246 region, now AR4274, which continued to grow
to three times its October size. Above all, on November 9, 10, and
11, it produced a series of three large solar flares, each of which
was significantly more powerful than the previous one, including an
increase in the energy of the ejected protons by one order of
magnitude.

"The particle cloud from the second flare was faster than the one
from the first. It caught up with and cannibalized it, reaching
Earth after midnight UT on November 12 and causing powerful
geomagnetic disturbances accompanied by auroras visible at
mid-latitudes. It had the greatest impact on the ionosphere on
November 12, when MUF values dropped and attenuation increased.
After that, however, shortwave propagation conditions behaved very
unusually and interestingly.

"A sporadic-E layer appeared, ionospheric waveguides were formed,
allowing communication with very low transmitter power,
trans-equatorial routes opened up excellently, and, conversely,
routes leading through the auroral oval closed. The propagation of
radio waves through the polar region was further complicated by
attenuation in the polar cap (PCA).

"Until the AR4274 region fades away in a few days, we can expect
more similar surprises, although probably not as powerful. Solar
activity will begin to decline in the coming days, with geomagnetic
activity likely to decline a little later."

The latest report from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at, https://www.youtube.com/watch?v=RMSpOSTrcS4[3] .

The Predicted Planetary A Index for November 15 to 21 is 5, 10, 10,
5, 5, 12, and 10, with a mean of 8.1.  Predicted Planetary K index
is 2, 3, 3, 2, 2, 4, and 3, with a mean of 2.7.  Predicted
10.7-centimeter flux is 170, 165, 170, 165, 160, 155, and 155, with
a mean of 162.9.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[4] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[5]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[6] . Information and
tutorials on propagation can be found at, http://k9la.us/[7] .

Also, check this:

https://bit.ly/3Rc8Njt[8]

"Understanding Solar Indices" from September 2002 QST.

 


[1] http://Space.com
[2] http://Spaceweather.com
[3] https://www.youtube.com/watch?v=RMSpOSTrcS4
[4] http://www.arrl.org/propagation
[5] http://arrl.org/propagation-of-rf-signals
[6] http://arrl.org/the-sun-the-earth-the-ionosphere
[7] http://k9la.us/
[8] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

11/21/2025

Solar activity has remained low this past week. The largest flare
was a C9.9 on November 19 from a region just beyond the NE limb near
N17. Region 4284 grew slightly in the early part of the period but
was in decay after November 19.

New Region 4287 was numbered. A Type II radio sweep (estimated at
695 km/s) was observed on November 19 at 2215 UTC, likely associated
with a B9.0 flare from just beyond the east limb. No Earth-directed
CMEs were observed. Solar activity is expected to be at low levels,
with slight chance for moderate levels (R1-R2/minor-moderate) to
November 21.
 
Solar wind parameters were at nominal levels. Solar wind speed
ranged from 346 - 421 km/s. Total field ranged from 4-8 nT while the
Bz component was between +8/-2 nT. Phi angle was predominantly
negative. By late November 20, a negative polarity coronal hole high
speed stream (CH HSS) is expected to become geoeffective, causing a
minor enhancement in the solar wind.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, November 20, 2025, by F. K. Janda, OK1HH:

"Solar activity over the last three months has fluctuated fairly
regularly within an approximately 27-day period, determined by the
rotation of the Sun. The positions of active longitudes do not
change much, which makes it relatively easy to predict not only
solar but also geomagnetic activity. However, we are still close to
the 11-year maximum, so the large solar flares on November 9, 10,
and 11 were not a major surprise.

"However, the fact that the coronal plasma clouds from the first two
flares merged (the second, faster one caught up with the first) and
caused a massive geomagnetic disturbance on November 12 could have
been a surprise.

"The massive disturbance lasted only until November 13, followed by
alternating calm days on November 14-15 and November 18-19 with
turbulent days, for which a more accurate forecast was not possible.
We are likely to see an increase in solar activity during the third
3rd of November and the first 3rd of December, with increased
geomagnetic activity most likely expected in the last days of
November and the first days of December. However, the regularity of fluctuations in solar and geomagnetic activity will end during this
period, while it is advisable to pay attention to newly emerging
active regions and the shift of coronal holes on the Sun."

High Speed Stream activity is expected to wane through November 22.
Solar wind speeds in the 450-550 km/s range are likely based on
recurrent values.  The geomagnetic field is likely to reach
unsettled conditions on November 22 due to waning solar wind
enhancements. Mostly quiet conditions are expected on November 23.

Spaceweather.com[1] for November 21 reports that Sunspot 4274, which
caused the Veteran's Day aurora and radiation storm, will be back
after Thanksgiving.

The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=FOLDm_N6ft8[2] .

The current Solar Cycle Progression from the NOAA/Space Weather
Prediction Center can be found at, https://www.swpc.noaa.gov/products/solar-cycle-progression[3] .

The Predicted Planetary A Index for November 22 to 28 is 8, 5, 15,
18, 25, 20, and 10, with a mean of 14.4.  Predicted Planetary K
Index is 3, 2, 4, 5, 5, 5, and 3, with a mean of 3.9.
10.7-centimeter flux is 110, 105, 110, 110, 110, 120, and 130, with
a mean of 113.6.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[4] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[5]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[6] . Information and
tutorials on propagation can be found at, http://k9la.us/[7] .

Also, check this:

https://bit.ly/3Rc8Njt[8]

"Understanding Solar Indices" from September 2002 QST.

 


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=FOLDm_N6ft8
[3] https://www.swpc.noaa.gov/products/solar-cycle-progression
[4] http://www.arrl.org/propagation
[5] http://arrl.org/propagation-of-rf-signals
[6] http://arrl.org/the-sun-the-earth-the-ionosphere
[7] http://k9la.us/
[8] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

12/05/2025

Solar activity was at low levels this past week with only C class
flares. Region 4294 remains the largest region on the disk but is
appearing to be simplifying magnetically. Region 4296, on the other
hand, gained a delta region in its intermediary region, though with
no corresponding increase in flare activity as of yet. New flux
emerged along the eastern side of Region 4298, resulting in several
C flares throughout the reporting period. Region 4299 also developed
a delta region in its primary spot but no appreciable shear was
observed. Region 4301 developed, was numbered, but was otherwise
unremarkable. No Earth directed CMEs were observed in available
coronagraph imagery.
 
Isolated to occasional M class flares are expected through December
6, with a chance for X class flares, given past flare history, and
the potential of current active regions on the disk.
 
The environment will likely remain enhanced due to fast solar wind
conditions through December 6.

M class flares (R1 to R2/Minor to Moderate) are likely, with slight
chance for X flares (R3 Strong or greater), through 12 Dec due
primarily to the flare potential of Region 4294.

Geomagnetic activity is likely to reach active levels on December 3
and 6, and G1 (Minor) storm levels on December 4 and 5, driven by
influences from a negative polarity CH HSS.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, December 4, 2025, by F. K. Janda, OK1HH:

The significant increase in solar activity since the beginning of
December has finally confirmed the original assumption that the
current 25th eleven year solar cycle will have two peaks. The first
occurred last October, while we have been eagerly awaiting the
second this year (especially in the fall). The increase in activity
at the end of this summer started promisingly, but it was only the
first of several. It was only after the large solar flare on
November 11, 2025, which was the largest since October 3, 2024, that
it was possible to estimate that the second maximum was approaching.

High solar activity period can be expected during the first half of
December, while it is a bit of a shame that it did not occur a week
or two earlier. This would have been particularly appreciated by
shortwave radio amateurs, as the telegraph part of the largest
competition, the CW WW DX Contest,  traditionally takes place
during the last weekend of November.

Although the current parameters of high speed solar wind do not
create exactly the structure of the Earth's ionosphere that we would
like, at least the highest usable frequencies allow connections to
be established on all shortwave bands. During December, we are
likely to experience another increase in solar activity in the last
third of the month, preceded by several days of increased
geomagnetic activity.

The latest video report from Dr. Tamitha Skov, WX1SWW, can be found
on Youtube.

The Predicted Planetary A Index for December 6 to 12 is 12, 10, 8,
5, 5, 5, 8 with a mean of 7.5. Predicted Planetary K Index is 4, 3,
3, 2, 2, 2, and 3, with a mean of 2.7. 10.7 centimeter flux is 190,
190, 190, 190, 185, 180, and 180, with a mean of 186.4.
 
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.
 


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

01/23/2026

Solar activity reached moderate levels with two M-class flares
earlier this week.
 
The first flares occurred on January 21 in regions 4345 and 4349.
Region 4345 continued to show development, as well as region 4342.
Region 4341 was a main contributor to the C-level activity of the
day, including a larger C-class flare on January 21. No
Earth-directed CMEs were observed in the available coronagraph
imagery.
 
Solar activity is likely to be at moderate (R1/R2, minor/moderate)
levels, with a slight chance for X-class flares (R3-strong) on
January 24, primarily due to the magnetic potential of Regions 4341,
4342 and 4345.
 
Solar wind parameters reflected Coronal Mass Ejection (CME)
influence transitioning into a high-speed stream paradigm, with the interplanetary magnetic field returned to largely enhanced
background levels. Solar wind speeds gradually decreased from about
800 km/s to 575 km/s at the end of the day. Phi angle remained in
the positive solar sector (away from the Sun), indicating the
coronal hole high speed stream (CH HSS) dominant influence over the
period. Solar wind parameters near Earth are expected to be
dominated by the CH HSS conditions in the next three days.
 
Geomagnetic field activity is likely to reach (G1-Minor) geomagnetic
storm levels on January 29 and unsettled to active levels on January
27 and 28, then 30 and 31, and then from February 4 to 11.  All
enhancements in activity are due to the anticipated influence of
multiple, recurrent Coronal Hole High Speed Streams.  The remainder
of the outlook period is expected to be mostly quiet.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, January 22, 2026, by F. K. Janda, OK1HH:

"A combination of favorable circumstances contributed to the
northern lights on the night of January 19-20 becoming one of the
main stories in the media in the following days. In particular, much
of Europe enjoyed very favorable weather conditions thanks to an
extensive high-pressure system, the center of which slowly moved
southward from Russia across Ukraine, the Black Sea, and Turkey to
the Middle East. In its western part, a dry, cold wind blew from the
south. As a result, the aurora borealis was observed as far south as
southern Europe, for example in southern France, northern Italy, and
Romania.

"Before the disturbance, a sunspot group AR4341, had been gradually
growing. Its magnetic configuration became increasingly complex,
while to the west and south of it lay the extensive coronal hole No.
15. Then, in a position near the center of the solar disk, very
favorable for the Earth to be hit by solar wind, a proton flare with
the highest concentration and energy of protons in the last 36 years
was observed. The beginning of the phenomenon was registered on
January 18 at 1727 UT, with a maximum at 1809 UT and an end at 1851
UT.

"A very fast particle ejection (CME) began on January 18 at 1748 UT,
lasted 5 hours, while was best observed around 1812 UT. The particle
flow velocity was extreme, ranging from 2900 up to 3500 km/s.
Therefore, the geomagnetic disturbance did not begin two to three
days after the flare, as is usual, but the very next day - January
19. The aurora borealis was visible for most of the night from
January 19 to 20, and even at mid-latitudes it had not only the
usual red color, but also, exceptionally, green.

"The G4 geomagnetic disturbance lasted 15 hours and was followed by
a G3 disturbance lasting 18 hours. The occurrence of numerous
inhomogeneities in the ionosphere caused large and variable
attenuation. On the other hand, the values of the critical
frequencies of the F2 ionospheric layer during the daytime in
mid-latitudes on January 19 and 20 were above average. The decline,
typical for the end of the disruption, did not occur until January
21.

"Solar activity at the end of December indicated that the maximum of
the eleven-year cycle is not yet over and will extend from 2024-2025
into part of 2026. During the rest of January, solar activity will
decline only very slowly, with a more significant decline occurring
after the beginning of February, when another longer geomagnetic
disturbance can be expected."

The Predicted Planetary A Index for January 24 to 30 is 5, 5, 5, 10,
15, 25, and 12, with a mean of 11.  Predicted Planetary K Index is
2, 2, 2, 3, 4, 5, and 4, with a mean of 3.14.  10.7 centimeter flux
is 180, 175, 170, 165, 160, 165, and 165, with a mean of 168.6.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.

 


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

07/06/2026

A series of M-class flares - all from Region 4479 - pushed solar activity to high levels this week. The largest of the flares was an M3.5 on July 1.
 
An earlier flare from this region, M1.3 accompanied by a 1N H-alpha flare which peaked late July 1, appears to have been associated with dimming and a coronal mass ejection (CME) first identified in CCOR-1 imagery. Initial analysis suggests the CME has an Earth-directed component, although the speed derived from the available imagery was only 300-450 km/s. Further analysis is needed to increase confidence.
 
Flux emergence and some consolidation around the leader and trailer spots was observed in Region 4479 during the period. Region 4478 produced an M8.5/2b flare on July 1 following occasional C-class flaring. This region also exhibited flux emergence in the intermediate spots and around the leader spot. Finally, Region 4480 was quiescent although some intermediate spots developed.
 
Solar activity is likely to decrease to moderate levels (R1-R2, minor-moderate) with a slight chance for X-class flares (R3-strong), particularly from Region 4479.
 
Solar wind parameters were enhanced with CME passage. Solar wind speeds have ranged from approximately 360 - 425 km/s. The CME from June 30 is expected to arrive early on July 3, bringing disturbed solar wind conditions that are expected to last into July 4. There is enough uncertainty around the CME timing that an arrival mid-to-late on July 2 is possible.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 2, 2026, by F. K. Janda, OK1HH:

Near the extensive active region AR4478, which the Solar Orbiter had been observing for several days before it rose on the southeastern limb of the solar disk, a small region, AR4479, was initially discovered. Both regions grew rapidly in the following days, while the configuration of their magnetic fields indicated nearby increased eruptive activity. High-energy flares occurred primarily on and after June 30, while some were accompanied by CMEs.

Because the CMEs occurred near the solar central meridian, Earth was strongly affected by an intensified solar wind. Shortwave propagation conditions were favorable during the so-called positive phase of the disturbance on June 30, but very unfavorable during the negative phase on July 1. A similar pattern may recur in the coming days!

The predicted Planetary A Index for July 7 to July 12 is 14, 5, 5, 12, 15, 12, and 8, with a mean of 10.1. The predicted Planetary K Index is 4, 2, 2, 4, 4, 4, and 3, with a mean of 3.3. Predicted 10.7 centimeter flux is 130, 125, 125, 125, 120, 125, and 120, with a mean of 124.3.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

07/10/2026

Solar activity reached moderate levels with an M1.5/1N flare on July 8 from Region 4482.

There are currently five numbered regions on the visible disk. Region 4482 demonstrated continued growth and developed a delta spot within its trailing spot group. Region 4485 displayed new flux emergence. Regions 4486 and 4487 were newly numbered during the period. Region 4481 was stable and remained an unremarkable unipolar group.

No Earth-directed CMEs were observed in available coronagraph imagery.

Solar activity is expected to remain at low levels through July 11, with a high chance for M-class (R1-R2/minor-moderate) flares and a slight chance for X-class (R3/strong and greater) events. This flare probability is almost entirely due to the complexity and potential of Region 4482.

Solar wind parameters reflected near ambient background conditions. Solar wind speeds were generally near 400 km/s. The phi angle was predominantly in the positive sector.

Enhancements are anticipated to begin on July 9 and continue through July 11 with the arrival of a co-rotating interaction region (CIR) ahead of a negative polarity coronal hole high-speed stream (-CH HSS).

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 9, 2026, by F. K. Janda, OK1HH:

The power flux of solar radio noise at a frequency of 2800 MHz (at a wavelength of 10.7 cm), which is measured precisely every day at noon local time in Penticton, Canada, and is referred to as the "solar flux," remains at a relatively low level. The reason is that the number of observed sunspot groups on the solar disk dropped to just three on July 7, the lowest number recorded during a single solar rotation (the following day, their number increased to five). The largest active region, NOAA 4482, which we observe in the southeast of the solar disk, has not changed significantly in size and continues to produce moderate-intensity flares on a regular basis. All three coronal holes are currently relatively far from it. The intensity of the solar wind is changing only slightly; periods of increased geomagnetic activity alternate with quiet days, making it impossible to accurately predict future developments.

A more pronounced increase in solar activity is expected in the second half of July (with a gradual increase in solar flux up to 180 s.f.u.). More significant geomagnetic activity can be expected if major solar flares occur, especially if they occur near or west of the central meridian. This is likely to happen sometime in the second half of July.

The predicted Planetary A Index for July 11 to 17 is 12, 8, 5, 5, 5, 10, and 8, with a mean of 7.6. The predicted Planetary K Index is 4, 3, 2, 2, 2, 3, and 3, with a mean of 2.7. Predicted 10.7 centimeter flux is 125, 120, 125, 130, 135, 135, and 135, with a mean of 129.3.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

07/20/2026

Solar activity has remained at low levels, with an occasional
low-level C-class flaring observed, including a C3.3/Sf flare on July
15 from Region 4489. The largest event of the period, a long-duration
C8.9 flare that peaked on July 15, originated from a returning region
on the eastern limb. This region is not yet numbered and will be
assessed once it has become visible from Earth's perspective, but the
latest imagery from Solar Orbiter suggested only a simple and rather
average bipolar group with a relatively small penumbra.
 
There are two numbered sunspot regions on the visible disk. Region
4482 showed minor new flux emergence behind its mature primary spot,
developing a bipolar configuration. As Region 4489 rotated further
into view and limb foreshortening effects decreased, very small opposite-polarity trailing spots became visible, making it a stable
bipolar group. Additionally, a small, magnetically simple, region
tracked in Solar Orbiter imagery has begun to rotate over the east
limb near S10. No Earth-directed CMEs were observed in available
coronagraph imagery.
 
Solar activity is expected to remain at low levels through July 18,
with a slight chance for M-class (R1-R2/minor-moderate) flares,
primarily driven by active regions anticipated to rotate onto the
visible disk over the next few days.
 
Solar wind parameters reflected possible combined glancing coronal
mass ejection (CME) effects and subsequent weak positive polarity
coronal hole high-speed stream (+CH HSS) influences.
 
A return to more ambient-like conditions is expected over the next
three days.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere,  July 16, 2026, by F. K. Janda, OK1HH:

The significant decline in solar activity throughout the first half
of July is clearly illustrated by the solar flux values, which fell
from 203 s.f.u. (July 2) to 100 s.f.u. (July 14-15), as well as by
the number of sunspot groups, which dropped from five to two. A
significant drop in the critical frequencies of the F2 layer began as
early as July 4 during the geomagnetic disturbance of July 4-5, and
due to the sharp decline in solar activity, these values returned to
average levels only very slowly in the following days. Consequently,
the sporadic E layer had an even greater impact on shortwave
propagation (particularly in the mid-latitudes of Europe on July
14-16).

The increase in solar activity, which is expected to begin as early
as the end of this week, while should last nearly until the end of
the month, will result in significantly better shortwave propagation
conditions than those experienced in the first half of the month.
More significant changes (possibly an initial rise, but then very
likely a temporary drop in MUF) will likely be caused by a
geomagnetic disturbance, which is tentatively expected on July 21-22.

The predicted Planetary A Index for July 18 to 24 is 5, 5, 5, 5, 12,
10, and 7, with a mean of 7.0. The predicted Planetary K Index is 2,
2, 2, 2, 4, 3, and 2, with a mean of 2.4. Predicted 10.7 centimeter
flux is 135, 135, 135, 135, 135, 135, and 135, with a mean of 135.0.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

07/24/2026

Solar activity continued at moderate levels as Region 4493 produced an M3.6 flare on July 22, which was the largest event of the period and was associated with a 10.7-centimeter radio burst of 200 solar flux units (sfu). Additionally, 4493 produced a C3.4 flare on July 22, which was associated with another 10.7-cm radio burst of 150 sfu.
 
Region 4493 continued to undergo consolidation in its leading and trailing spots, but showed signs of new flux emergence in its intermediate area during the early hours of the reporting period. Region 4494 developed new, simple spots, but remained uni-polar. The remaining two numbered active regions were relatively stable and quiet.
 
A filament eruption NW of Region 4493 on July 21 was modeled and assessed to be at least partially Earth-directed. While modeling efforts suggest that a bulk of the material should pass north and ahead of Earth s orbit, this is low confidence given the faintness of this event in Sun-Earth line-focused coronagraph imagery and compounded by likely interaction with the coronal hole in the vicinity of the source location.
 
Additional M-class flare activity (R1-R2 radio blackouts) is likely through July 25 primarily due to the flare potential currently exhibited by AR 4493.
 
Solar wind parameters were mildly enhanced under a sustained negative polarity coronal hole high-speed stream (CH HSS) regime and a possible secondary Co-rotating Interaction Region (CIR). Solar wind speeds were roughly between 400 and 482 km/s.
 
The current regime is expected to largely continue through July 25. Additional enhancements are possible beginning late on July 23 due to a coronal mass ejection (CME) that left the sun on July 20, with stronger enhancements arriving by early on July 24 with the arrival of the aforementioned CME event from July 21.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 23, 2026, by F. K. Janda, OK1HH:

A relatively large sunspot group, which was already very conspicuous in images from the SOLAR ORBITER spacecraft, was designated NOAA 4493 after its discovery as an active region on the northeastern limb of the solar disk. It produced class C and M flares on a daily basis. It is currently located in the northwest of the solar disk. As it grew, it disrupted a long north-south coronal hole and remains the largest and most complex sunspot group on the visible disk, accounting for most of the observed eruptive activity. The eruption observed within it on July 20 was accompanied by a CME. The ejected particles triggered a geomagnetic disturbance on the afternoon of July 23.

As a result of this activity, the ionosphere is currently undergoing variable conditions, characterized albeit irregularly by a pronounced presence of the summer sporadic E layer in the Earth s northern hemisphere. In the coming days, geomagnetic activity should begin to gradually decline (no earlier than July 25). Increased solar activity will likely persist almost until the end of the month. Conditions for ionospheric radio propagation will therefore remain variable, with irregular occurrences of relatively very favorable days.

The predicted Planetary A Index for July 25 to 31 is 5, 5, 5, 5, 5, 5, and 5, with a mean of 5.0. The predicted Planetary K Index is 2, 2, 2, 2, 2, 2, and 2, with a mean of 2.0. The predicted 10.7 centimeter flux is 125, 125, 120, 118, 118, 115, and 112, with a mean of 119.0.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

08/01/2026

Solar activity has remained at low levels. Region 4494 exhibited decay in its trailing spots as its flare activity subsided. Region 4498 rotated into better viewing positioning, revealing mixed polarity just behind its large leading spot, and was responsible for a handful of low-level C-class flares.

Region 4499 underwent evolution, gaining additional spots and producing a low-level C-class flare. Region 4501 rapidly emerged this period, developed rudimentary penumbra on its leading and trailing spots, produced a low-level C-class flare and was thus subsequently numbered. The remaining numbered active regions were unremarkable in relation.

No Earth-directed CMEs were observed in available coronagraph imagery.

Solar activity is expected to be low with a chance for M-class flares (R1-R2, minor-moderate) through August 1.

Solar wind parameters were at nominal levels. Solar wind speeds roughly ranged from 310 km/s to 401 km/s. A disturbed solar wind environment will likely return July 30 due to the prospect of combined positive polarity coronal high speed stream (CH HSS) effects and coronal mass ejection (CME) arrivals from events that left the Sun on July 26 - 27. An additional disturbance is likely on August 1 with the arrival of an additional CME that left the Sun late on July 27.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 30, 2026, by F. K. Janda, OK1HH:

During the last third of July, solar activity initially rose, while remained at a higher level until the end of the month. Although solar flares occasionally reached moderate intensity, while were exceptionally accompanied by coronal mass ejections, the Earth was not affected by them (though this could still happen by the end of July or early August, partly because there is a coronal hole in the southwestern part of the disk). There is only one active region on the far side of the Sun. Therefore, as the nine regions currently being observed fade, overall activity will decline shortly after the beginning of August.

Shorter periods of increased geomagnetic activity may still occur in late July and at the beginning and end of the first third of August. Following the expected decline in solar activity, these will be followed at irregular intervals by shorter periods of deteriorated ionospheric conditions for shortwave propagation.

The predicted Planetary A Index for July 31 to August 6 is 8, 5, 5, 5, 12, 15, and 10, with a mean of 8.6. The predicted Planetary K Index is 3, 2, 2, 2, 4, 3, and 3, with a mean of 2.7. Predicted 10.7 centimeter flux is 135, 130, 125, 125, 125, 120, and 125, with a mean of 126.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

08/07/2026

Solar activity has been at low levels, with occasional B-class flaring and isolated low-level C-class flares observed. The largest event of the period was a C1.6/Sf flare on August 5 from Region 4502.
 
The six numbered sunspot regions on the visible disk are mostly stable or in varying stages of decay. Region 4498 showed a slight decrease in penumbral extent. Region 4499 declined in length and area, though limb foreshortening hindered complete characterization of its magnetic structure. Region 4500 weakened in its leading spot. Region 4501 lost its trailing spots, decaying into a unipolar group.
 
Region 4502 exhibited consolidation across both magnetic poles. Region 4503 was limited by foreshortening near the southeast limb, but appeared to show modest new flux emergence in its trailing spots to become a bipolar group.
 
No Earth-directed coronal mass ejections (CMEs) were observed in available coronagraph imagery.
 
With ongoing region decay and several active regions in the western hemisphere expected to rotate off the disk over the coming days, there is a decreasing chance for M-class (R1-R2/minor-moderate) flares August 6. Current Solar Orbiter Helioseismic and Magnetic Imager (HMI) imagery suggests no significant returning regions during the forecast period.
 
Solar wind parameters remained at quiet, ambient, levels throughout the period. Solar wind speeds reflected a slow wind regime, gradually declining from early values near 400 km/s down to approximately 345 km/s late in the period. The phi angle remained predominantly in the positive (away from the Sun) sector.
 
Solar wind parameters are expected to remain in a slow wind regime through early August 7. Later in the day, enhancements are anticipated to begin due to the arrival of CMEs that departed the Sun on August 3. These CME enhancements may persist into August 8, alongside potential weak influences from a negative polarity coronal hole high-speed stream (-CH HSS) that is likely too far south to become significantly geoeffective.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 6, 2026, by F. K. Janda, OK1HH:

The effects of the expected decline in solar activity (within the context of the 27-day cycle), which began before the end of July, were exacerbated by the geomagnetic disturbance that occurred on August 2 3. The effects of this decline will still be felt in the ionosphere during the first third of August. The second third of the month will bring an improvement. Then, in the final third, when solar radiation levels will once again be elevated, the approaching fall will also have a noticeable and positive effect on the ionosphere.

The Predicted Planetary A Index for August 7 to August 13 is 5, 5, 5, 5, 8, 8, and 5 with a mean of 5.9. The Predicted Planetary K Index is 2, 2, 2, 2, 3, 3, and 2 with a mean of 2.3. Predicted 10.7 centimeter flux is 110, 105, 105, 105, 105, 105, and 110 with a mean of 106.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

08/17/2026

Weekly Highlights and Forecast, August 17, 2026, by NOAA Space Weather Prediction Center:

Solar activity ranged from very low to low levels throughout the
period. No R1 (Minor) or greater events were observed. The largest
flare was a C8.2/Sn at 16/1928 UTC from Region 4506. An associated
CME was observed in LASCO C2 imagery following the C8.2 flare, but
analysis is ongoing in order to determine any Earth-directed component.
Other activity included the lift-off of av large filament near S16E22
at 14/0332 UTC which produced a CME that is expected to arrive on 17-18 Aug.

Geomagnetic field activity is expected to reach active levels on
17-18 Aug due to the anticipated arrival of a CME that left the Sun
on 14 Aug. Active conditions are expected again on 21-22 Aug and 04
Sep due to the influences of a CH HSS. Quiet and quiet to unsettled
conditions are expected to prevail throughout the remainder of the
outlook period.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 13, 2026, by F. K. Janda, OK1HH:

It appears that solar activity will remain relatively low for a few more days before mid-August; however, it is more likely that July s surprise will repeat itself and solar activity will increase after a few days. This would be a more favorable scenario for possible future developments in the Earth s ionosphere. Although the sporadic E layer often plays a significant role in the ionosphere at mid-latitudes, its season will gradually come to an end.

Solar activity will rise in the second half of the month, while geomagnetic activity is expected to decrease on average. It is hard to imagine a better scenario for future developments, and it appears that this one will at least partially come to pass.

The current solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=7od5srHvDsw&t=3s[1] .

The Predicted Planetary A Index for August 14 to August 20 is 5, 5, 5, 15, 12, 20, and 8 with a mean of 10. The Predicted Planetary K Index is 2, 2, 2, 4, 4, 5, and 3 with a mean of 3.1. Predicted 10.7 centimeter flux is 95, 95, 95, 100, 105, 105, and 105 with a mean of 100.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and
tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check this:

https://bit.ly/3Rc8Njt[6]

"Understanding Solar Indices" from September 2002 QST.


[1] https://www.youtube.com/watch?v=6SoYfTnrudc
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS

08/28/2026

Solar activity reached moderate levels this week. Region 4513 was responsible for an M2.2/1B flare that reached its peak on August 26. This event was accompanied by a 10.7-centimeter radio burst that reached 140 solar flux units (SFU) and a type II radio sweep with an estimated shock speed of 930 km/s despite its relatively impulsive nature. No resulting coronal mass ejection (CME) has been observed in available coronagraph imagery as of the time of this report.
 
Other activity of note since the last reporting period included an easterly CME first seen in two LASCO C2 coronagraph imageries on August 25.
 
The first event likely originated from the vicinity of Region 4513 around August 25 while no definitive source could be identified with any confidence for the latter. Nevertheless, both of these events are currently being modeled and assessed to determine the presence of an Earth-directed path.
 
Solar activity will likely remain at minor-moderate (R1-R2) levels, with a slight chance for strong (R3) activity, through August 28, mostly due to the flare history and potential of Region 4513.
 
Solar wind parameters were at undisturbed levels with solar wind speeds between ~300-340 km/s, total field at or below 5 nT and Bz northward or near neutral. Phi angle was predominantly negative.
 
Nominal solar wind conditions are expected to continue until midday August 27, when the onset of a positive polarity coronal hole high speed stream (CH HSS) influence is anticipated. Additional solar wind disturbances, with increased solar wind densities and total IMF, are likely on August 28 due to the impact of the CMEs that left the Sun on August 25.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 27, 2026, by F. K. Janda, OK1HH:

More or less in line with expectations, total solar activity has been slightly elevated during the last third of August, including flare activity we have been observing moderate-sized flares since August 24, peaking on August 25. Most sunspots and all larger groups are now located in the western half of the solar disk, which increases the likelihood of rising geomagnetic activity, which had been low for a relatively long period beginning on August 21. This resulted in above-average shortwave propagation conditions, including propagation in the Earth s polar regions.

Solar activity is expected to remain elevated for the remainder of August and will drop significantly in early September. Geomagnetic activity, however, will increase, whilst is likely to remain higher for the rest of August. Consequently, shortwave propagation conditions will no longer be as consistent as in recent days; instead, there will be a decrease in usable frequencies and an increase in attenuation. The beginning of September will be calmer, albeit with slightly lower critical frequencies in the F2 layer of the ionosphere.

The Predicted Planetary A Index for August 28 to September 3 is 10, 8, 5, 5, 5, 5, and 5 with a mean of 6.9. The Predicted Planetary K Index is 3, 3, 2, 2, 2, 2, and 2 with a mean of 2.3. Predicted 10.7 centimeter flux is 120, 120, 120, 120, 120, 120, and 115 with a mean of 119.3.
 

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and
tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt
---
■ Synchronet ■ Whiskey Lover's Amateur Radio BBS