ZCZC AP18
QST de W1AW
Propagation Forecast Bulletin 18 ARLP018
From Tad Cook, K7RA
Seattle, WA May 6, 2022
To all radio amateurs
SB PROP ARL ARLP018
ARLP018 Propagation de K7RA
https://www.spaceweather.com reported on May 4 at 0859 UTC that an M5 solar flare erupted from sunspot group AR3004, causing a shortwave radio blackout over the Middle East and Africa.
Please see https://bit.ly/3vKzelk
A recent flare update:
https://bit.ly/3OXvuo8
Solar activity was lower this week, even though we could see sunspots every day.
Average daily sunspot numbers dropped from 109.3 to 68.6, while average daily solar flux went from 156 to 120.
Average daily geomagnetic indices were only slightly higher, with average planetary A index changing from 9.1 to 10.7, and middle latitude A index from 8 to 9.3.
Predicted solar flux looks low for the next month, even dipping below 100 in early June. In fact, from Wednesday to Thursday the predicted solar flux for the first week of the forecast dropped dramatically.
For a comparison, see this week’s ARRL Letter at, http://www.arrl.org/arrlletter?issue=2022-05-05 .
Predicted values are 118 on May 6-8, then 115, 110 and 112 on May 9-11, then 115, 115 and 120 on May 12-14, 125 on May 15-18, 127 on May 19-20, then 130, 128, 125, and 122 on May 21-24, 118 on May 25-26, then 114 and 110 on May 27-28, 105 on May 29-31, then 102 and 100 on June 1-2, 97 on June 3-5, then 99, 102 and 108 on June 6-8, then 115 on June 9, 120 on June 10, and 125 on June 11-14.
Predicted planetary A index is 5 on May 6, 8 on May 7-8, 5 on May 9-12, then 8, 10 and 8 on May 13-15, 5 on May 16-19, then 12 and 8 on May 20-21, 5 on May 22-23, 18 on May 24, 15 on May 25-27, then 8, 15 and 8 on May 28-30, then 5 on May 31 through June 8, then 8, 1, and 8 on June 9-11.
These predictions are from forecasters Housseal and Dethlefsen of the USAF 557th Weather Wing.
Recent flare activity in the news:
https://bit.ly/39vn8Uq
https://bit.ly/38YBfRO
https://bit.ly/3P0IfOX
https://bit.ly/3ydNeFM
https://bit.ly/3FhULFc
Thanks to KA3JAW for this story:
https://bit.ly/3kLmchd
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere from OK1HH:
“We have seen more of large solar flares this year, but it was usually by night in Europe. On April 30, the first major flare finally occurred during the day, thanks to which we were able to observe the ShortWave Fadeout (SWF) in the western part of the Old World. Solar X-rays caused abnormally high ionization in the ionospheric D region, where attenuation increased significantly. Our shortwave receivers fell silent at 1337 UTC.
“The solar flare peaked at 1347 UTC, ending at 1352 UTC. Only then could the attenuation in the ionospheric D region begin to decline and signals other than those coming via ground wave gradually appeared. Solar activity began to rise again mainly due to active area No. 3004, which emerged on May 2, and grew rapidly.
“Its magnetic structure became more complex with increased energy, with significant eruptions up to several times a day. In addition, they were often accompanied by type IV radio noise bursts, which indicated that the solar plasma cloud had left the Sun. As Group 3004 is now facing approximately toward us, we can expect at least one of the clouds to hit Earth, causing a disturbance. Perhaps we will see further improvement in the shortwave propagation conditions, during the possible positive phase of its development.”
KA3JAW sent this report about signals heard on the 8 meter band:
“On Saturday, April 30, 2022, between 1607-1632 UTC I received WM2XEJ in Grid Square EM82 calling CQ using digital mode FT8 on the experimental 8-meter (40 MHz) band via short-haul sporadic-E. Distance was 670 miles (1078 km), with an azimuth of 220 degrees.
“The 8-meter experimental band is within the worldwide Industrial-Scientific-Medical (ISM) segment between 40.660 to 40.700 MHz with a 40 kHz bandwidth, center frequency on 40.680.
“Licensed users are Fixed, Mobile and Earth exploration-satellite service.
“WM2XEJ is an FCC Part 5 Experimental Radio Service station operated by Tom Mills, WB4JWM in Eatonton, Georgia. Tom is authorized to operate at 400 watts of Effective Radiated Power (ERP) using CW, SSB, digital modes FT4, FT8, WSPR, and Q65.
“Tom uses an Icom IC-9100 rig into a vertical loop antenna giving about 300 watts of ERP.”
Amateur radio has 8 meter allocations in the UK, Slovenia, Denmark, and South Africa.
Here is a blog devoted to 8 meters:
https://ei7gl.blogspot.com/p/40-mhz.html .
If you would like to make a comment or have a tip for our readers, 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/.
Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.
Sunspot numbers for April 28 through May 4, 2022 were 118, 90, 50, 36, 69, 53, and 64, with a mean of 68.6. 10.7 cm flux was 132.2, 123.5, 119.7, 109, 111.9, 113.8, and 130.1, with a mean of 120. Estimated planetary A indices were 14, 15, 18, 9, 6, 7, and 6, with a mean of 10.7. Middle latitude A index was 11, 10, 16, 9, 6, 7, and 6, with a mean of 9.3.
NNNN
/EX
Source: W1AW Bulletin via the ARRL.