venerdì 10 giugno 2022

Propagation de K7RA

From Tad Cook, K7RA
Seattle, WA June 10, 2022
To all radio amateurs

Hard for me to believe, I had to blink to make sure, but on
Wednesday, June 8 for the first time this calendar year there were
no sunspots, even though two new sunspot regions appeared on June 4.

Average daily sunspot number declined to 44 from 52.9 last week.
Average daily solar flux was only 99.4, down from 104.3 last week
and 158.8 the week before.

News about the first spotless day can be found here:

https://bit.ly/39cOiQk

I am grateful that on Thursday, June 9, a new sunspot group emerged,
bringing the sunspot number for the day to 17.

Predicted solar flux is 105 on June 10, 110 on June 11-16, 115 on
June 17, 120 on June 18, 125 on June 19-20, 150 on June 21, 110 on
June 22, 100 on June 23 through July 3, 105 on July 4-5, 110 on July
6-10, then 115 on July 11-13, 120 on July 14, and 125 on July 15-16.

Assuming the above prediction is true, this would mean average daily
solar flux rising from 99.4 to 109 over the next reporting week and
123 the next.

Predicted planetary A index is 5 on June 10-14, then 8, 12 and 8 on
June 15-17, 5 on June 18-22, then 12, 18, 10 and 8 on June 23-26, 5
on June 27 through July 9, then 12, 8, 12, 10 and 8 on July 10-14,
and 5 on July 15-19.

Despite the recent downturn, Solar Cycle 25 activity exceeds the
official forecast:

https://helioforecast.space/solarcycle

According to Spaceweather.com, May 2022 sunspot activity was the
highest it's been in eight years.

OK1HH wrote:

"As during the last solar revolution, solar activity has been low in
the last two weeks.

"On June 8, the Sun was even empty - no sunspots - R = 0.

"This is a remarkable development more than 2 years after the
beginning of Solar Cycle 25. However, during the last few hours,
rapid spots have been observed near the central meridian. In
addition, NASA's STEREO-A spacecraft is monitoring a probable group
of sunspots approaching beyond the northeastern edge of the Sun:

"https://stereo.gsfc.nasa.gov

"It should be followed by other groups of spots, which will increase
solar activity again.

"The Earth's magnetic field was largely quiet, except for an
increase in activity on June 6.

"The result was an improvement in the propagation conditions on June
6 and a degradation on June 7 and the morning of June 8. Gradual
improvement can be expected in the coming days."

W9NY wrote:

"Just got a new dipole up on 10 meters on my condo roof which is
over 400 feet off the ground overlooking Lake Michigan.

"Made a couple of contacts late this afternoon into Texas and
Louisiana S5-S6 and nothing else on the band, until a ZL called me
from New Zealand about 6:20 PM local time. He gave me an S9, and he
was S5. Just like the good old days on 10 meters!

"The ionosphere has to be working, I think, to get over to New
Zealand."

Some observations from K7RA on 6 and 12 meters this week:

On June 4, at 1745 UTC on 6 meter FT8 I worked KB1EFS/2 in Cape
Vincent, New York.

On pskreporter.info I saw that my signal was propagating along a
very narrow arc at 72-74 degrees received only by a concentration of
stations in the northeast USA. No real 6 meter antenna here, just a
32 foot end-fed wire, 4:1 UnUn and autotuner, mostly indoors on the
second floor of my 1907 all wood Craftsman home.

Just prior to that at 1730 UTC I seemed to be monitored only by
stations 2000-2500 miles from me in an arc with bearings 77-79
degrees with WA9WTK at the south and VE3TTP at the north.

On June 9 at 2300 UTC on 12 meters FT8 I am only heard by N4DB at 91
degrees, 2292 miles and K4BSZ at 94 degrees, 2276 miles. Then at
2320 UTC, WB4EVH at 2326 miles and 103 degrees bearing, at 2330 UTC,
VK5PJ at 8306 miles, 250 degrees.

Here is an article about aurora:

https://bit.ly/398hPdM

Mostly good info, except the statement about being half way through
this Solar Cycle. I guess we might be half way toward the peak.

Here is a link about the K-index:

https://bit.ly/3xnDrLc

Here is a nice solar image, and another interesting link:

https://bit.ly/3xlrB4B

https://bit.ly/3x9WNna

Amateur Astro photographer and his image:

https://bit.ly/3NILWYo

More information here:

https://bit.ly/3QcuX2a

Here is a 3-week movie of sunspot activity:

https://bit.ly/3zqGu87

If you would like to make a comment or have a tip for our readers,
please email the author at, k7ra@arrl.net.

For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals. For
an explanation of numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. More good
information and tutorials on propagation are at http://k9la.us/.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for June 2 through 8, 2022 were 59, 52, 75, 57, 45,
23, and 0, with a mean of 44.4. 10.7 cm flux was 100.9, 100.7,
100.9, 98.7, 96.4, 98.4, and 99.9, with a mean of 99.4. Estimated
planetary A indices were 5, 4, 4, 4, 10, 8, and 5, with a mean of
5.7. Middle latitude A index was 5, 4, 4, 5, 10, 11, and 5, with a
mean of 6.3.
NNNN
/EX

(ARRL)