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ARRL Propagation Bulletin ARLP010 (2022)

ARLP010 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7RA
Seattle, WA  March 11, 2022
To all radio amateurs 

ARLP010 Propagation de K7RA

On March 11 at 0431 UTC Australia's Space Forecast Centre issued
this warning:

"A slow coronal mass ejection has been observed late on 10 march,
and event modeling suggests arrival at the Earth late on 13 March.
Increased geomagnetic activity is expected for 14 March 2022."

We observed an active Sun this week. Geomagnetic indicators peaked
on Saturday, March 5 when Alaska's high latitude college A index
reached 42.

Again this week, sunspots covered the Sun every day. Average daily
sunspot numbers rose from 44 to 87.4, and average daily solar flux
went from 98.5 to 115.5. Geomagnetic indicators were also higher.
Average daily planetary A index increased from 7.3 to 11.4.

Predicted solar flux is 120 on March 11-12, 115 on March 13, 110 on
March 14-16, 105 on March 17, 100 on March 18-21, then 101 and 103
on March 22-23, 104 on March 24-27, then 110, 115 and 116 on March
28-30, 118 on March 31 through April 1, 120 on April 2, 116 on April
3-4, then 115 and 112 on April 5-6, 110 on April 7-9, then 108, 102,
98 and 99 on April 10-13 then 100 on April 14-17.

Predicted planetary A index is 12 on March 11, 5 on March 12-13,
then 10, 18, 15, 5 and 8 on March 14-18, then 12 on March 19-20, 15
on March 21, 7 on March 22-24, then 5, 10 and 8 on March 25-27, 5 on
March 28-29, then 10, 12, 25, 20 and 10 on March 30 through April 3,
5 on April 4-6, then 15, 20 and 12 on April 7-9, and 5 on April
10-13, then 8 on April 14, and 10 on April 15-16.

OK1HH wrote, "The power density of solar radio noise at a wavelength
of 10.7 cm, more briefly referred to as 'solar flux,' remains above
110 for a week. Because we see two more active areas beyond the
eastern limb of the solar disk (thanks to the STEREO Ahead
satellite), solar flux should stay that way for another week.

"The concurrence of increased solar activity with seasonal changes
during the approaching equinox results in improved conditions for
short-wave ionospheric propagation.

"Occasional irregular occurrences of a slight increase in
geomagnetic activity (as was the case on March 5-6) cause only a
slight deterioration. Possible recurrent disturbance is expected
until the beginning of April, probably already in its first days."

Russ Hunt, WQ3X wrote on March 4, "Yesterday I heard WA2BOT on 10m
FT8 working DX on the long path and aimed my beam due south. In just
over a half hour's time I worked 33 JAs, 2 DUs and VR2XYL. I had a
pileup 6 deep at times using 250w and 5 element Yagi at 50'. It was
probably the most exciting time I've had in the last 20 yrs. Today I
worked two more VR2s and 3 JAs also LP just after sunrise. Love them

A few hours later he wrote, "During the middle of the day we get
some VK/ZLs starting around 3 PM local time. But try sunrise and
sunset and you will find a lot of DX.

"I hear the 6s and 7s working a lot of Asia in the evening. Here we
get EU, Africa, and the middle east in the mornings. I've done WAC
about 4 or 5 times a week, but now running out of new stations to

Robert Strickland, KE2WY asked about a good source for the latest
daily sunspot numbers, and I sent him to this site:

On March 10, N9II sent some observations of last week's DX contest,
only a small portion presented here.

"I operated single band 15M in the ARRL DX contest but made a few
QSOs on other bands. 20M was open well to Africa and south in the
0100 UTC hour Saturday, some very loud Caribbean signals. 10M was
open for many hours to the south some booming signals even from LP
stations in Puerto Rico and Turks and Caicos and many HP stations
like J68HZ, St Lucia, PJ4G on Bonaire, and PJ2T, Curacao.

"On 15M, a disturbance and slightly low solar flux made for some
challenging conditions to Asia and northern Europe.

"Saturday evening the disturbance rendered Japan nearly completely
closed, with Sunday evening conditions fair with most signals less
than S9.

"I made 600 15M QSOs working 86 countries.

"On 10M CW starting 1414 UTC on March 8 I worked 3 new ones in a
row: 7Q6M, Malawi, 5X1NA, Uganda, and JY5HX, Jordan.

"Then on 10 SSB, Dov, 4Z4DX, Israel, on 10 CW V26K, Antigua, and
OA1F in Peru.

"Later on 17 CW V4/G0TLE, St. Kitts, then topping off with E51BQ on
South Cook Islands on 10 SSB at 2325 UTC.

"On 12m CW on the 9th at 1550 UTC I worked V26K. I called CQ on 10
SSB at 1557 UTC and was called by Spain, then Francisco, TT8FC in
Chad, ZS1PPY, South Africa, then 3B8HE in Mauritius. Today, the 10th
featured excellent high band propagation with today's solar flux
climbing to 127. I heard Indonesia peaking S8 on 15M SSB at 1340
UTC, then worked 4L1AN in Georgia at 1344 UTC (new), VU2DSI, India,
at 1353 UTC.

"Turning to 10M SSB, I found Selki, S01WS, Southern Sahara, and
CU1EZ, Azores for #100 on 10 SSB. Then at 1551 UTC for the next hour
10M blew wide open to Europe starting with Bulgaria, Italy, and

"Several stations with simple end fed wires were S9 and the loudest
signals were S9+20 dB or a bit stronger. This was one of the best
openings all Winter, but others were more widespread farther north."

Here is an email list for operators of, or anyone interested in, HF

The Vernal Equinox is in a little over a week, 1533 UTC on Sunday,
March 20, when Earth will be bathed in an equal amount of solar
radiation over both southern and northern hemispheres, good for HF
propagation. It is the first day of Spring in the northern
hemisphere and Fall in the southern.

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

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 .

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

Sunspot numbers for March 3 through 9, 2022 were 92, 77, 95, 82, 84,
93, and 89, with a mean of 87.4. 10.7 cm flux was 110.9, 113.1,
120.1, 115.7, 118.3, 115.3, and 114.8, with a mean of 115.5.
Estimated planetary A indices were 5, 10, 27, 18, 9, 6, and 5, with
a mean of 11.4. Middle latitude A index was 3, 7, 19, 13, 7, 5, and
4, with a mean of 8.3.


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