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The K7RA Solar Update


This reporting week (May 30 to June 5) our Sun was active, with nine
new sunspot groups.

One emerged on May 30, another on May 31, two more on June 1,
another on June 2, three more on June 3, and one more on June 4.

Average daily sunspot number rose from 124.6 to 183.4, and average
daily solar flux from 164.8 to 184.8.

Predicted solar flux is 190 on June 7-9, 170 on June 10-19, 180 on
June 20, 190 on June 21-23, 195 on June 24 and 25, 200 on June 26,
205 on June 27-29, 180 on June 30, then 185, 185 and 180 on July
1-3, 175 on July 4-7, 180 and 175 on July 8-9, and 170 on July

Predicted planetary A index is 5, 10 and 8 on June 7-9, 5 on June
10-18, 8 on June 19-20, then 5, 8 and 8 on June 21-23, and 5 on June
24 to July 6, then 8, 10, and 8 on July 7-9, and 5 on July 10-15.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - June 6, 2024 from F.K. Janda, OK1HH:

"The rise in solar activity is confirmed by the average sunspot
number for May, 171.7, which is the highest in 22 years. Plugging
this into the formula for calculating the smoothed 12-month average
gives 127.8 for last November. As a consequence of the high solar
activity, including CME flares, there were a large number of
geomagnetic storms in May. The largest of these occurred on 10-11
May, while accompanied by auroras, easily observable even at

"Shortwave conditions were above average on only six days out of the
entire month of May, and mostly poor on half of the days in response
to a total of seven one- to three-day disturbed intervals. The worst
day was May 11. In addition, a summertime sporadic-E layer
contributed to the erratic development, especially in the
mid-latitudes of the Northern Hemisphere.

"While the two large sunspot groups, AR3663 and AR3664 (AR3691 and
AR3697 in June), continue to have a magnetic configuration conducive
to the production of large flares, there are fewer of them than in
May, and the evolution of propagation conditions is therefore more
regular, and the occurrence of above-average days is more frequent.
The number of sunspot groups increased from seven to twelve during
the first six days of June.

"Although the sunspot number and the solar flux (which is the power
flux of solar radio noise at the 10.7 cm wavelength) may still be
increasing, a repeat of the large disturbances experienced in May is
unlikely in the near term."

On June 3, Glenn Packard, K4ZOT, wrote:

"I just received your Propagation Report and was reading it when a
near miracle happened. Hawaii 6M FT8 station (KH6HI) came in on my
JTAlert program here - South of Atlanta, GA - 06/3.  Also, worked
several west Coast stations (VE7DX, KF7PG, etc.) as well in rapid
succession before the band changed.  Very rare indeed to even hear a
HI station in Atlanta."

An article about Astrophotographer Andrew McCarthy:

The latest report from Dr. Tamitha Skov, WX6SWW:

Send your tips, reports, observations, questions and comments to When reporting observations, don't forget to tell us
which mode you were operating.

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 .

An archive of past propagation bulletins is at . More good
information and tutorials on propagation are at .

Also, check this QST article about Solar Indices:

Instructions for starting or ending email distribution of ARRL
bulletins are at .

Sunspot numbers for May 30 through June 5, 2024 were 144, 135, 194,
186, 208, 224, and 193, with a mean of 183.4. 10.7 cm flux was
172.9, 179.4, 188, 179.8, 186, 192.3, and 195.3, with a mean of
184.8. Estimated planetary A indices were 8, 12, 5, 5, 11, 8, and 7,
with a mean of 8. Middle latitude A index was 10, 14, 6, 5, 13, 8,
and 10, with a mean of 9.4.




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