Register Account

Login Help

ARRL Propagation Bulletin ARLP052 (2021)

ARLP052 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7RA
Seattle, WA  December 28, 2021
To all radio amateurs 

ARLP052 Propagation de K7RA

Solar activity was way up this week, and it was reflected in on-air
activity, especially on 10 meters. If only the ARRL 10 Meter Contest
were held a week later!

Average daily sunspot number jumped 100 points, from 24.4 last week
to 124.4 in the current reporting week, December 16-22.

Average daily solar flux increased from 82.9 to 125.

Average planetary A index went from 5 to 9.1, and average middle
latitude A index from 3.9 to 6.4.

It was great looking at every day and seeing the
Sun covered with spots.

Predicted solar flux over the next week looks quite promising, with
daily solar flux over 100 until the end of the year, then rising
above 100 on January 16-22, 2022. But the outlook issued on
Thursday, December 23 wasn't as optimistic as the one issued the
previous day.

Flux values are predicted at 130, 125, 120, 115 and 113 on December
24-28, then 110 on December 29-30, 85 on December 31, 2021, then 83,
81, 80 and 81 on January 1-4, 2022,  82 on January 5-6, then 83, 86,
90 and 92 on January 7-10, 95 on January 11-12, 96 on January 13-15,
then jumping up to 115 on January 16-17, then 114, 111 and 110 on
January 18-20, 108, 102 and 95 on January 21-23, then 90, 88, 87 and
85 on January 24-27, then dropping to a low of 80 on January 30
before rising above 90 after the first week in February.

Predicted planetary A index is 20, 12, 16, 8, 10 and 12 on December
24-29, 8 on December 30-31, 2021, then 5 on January 1-8, 2022, then
8 and 5 on January 9-10, 10 on January 11-12, 5 on January 13-14,
then 8, 12, 18, 12 and 8 on January 15-19, 5 on January 20-22, then
8, 10, 8 and 8 on January 23-26, and 5 on January 27 through
February 4.

These observations from J.K. Janda, OK1HH:

"Unlike meteorologists, for example, we do not have reliable models
of the Sun's behavior and subsequent changes in the Earth's
magnetosphere and atmosphere. Therefore, we did not expect the
current increase in activity. On the other hand, we can consider
them as another promise of a higher maximum of the 25th cycle.

"Most spots are in the southern hemisphere of the Sun, M-class
flares are observed in both hemispheres, the solar flux has climbed
from the minimum to the highest values in two weeks and the speed of
the solar wind remaining increased in ten days.

"Geomagnetic activity increased relatively only slightly, only after
the spot activity moved to the western half of the solar disk. These
changes were mostly favorable for the changes in the shortwave
propagation conditions. Before the beginning of the ascent, as
shortest the 18 MHz band was regularly opened for the DX contacts,
while in last days the 21 MHz band is opened relatively reliably.

"As a result of the eruptions of previous days, the Earth's magnetic
field activity should increase around December 24th and then
probably again on 27th.

"Before the end of the year, there will return a significant
decrease in solar activity. Its next growth is expected around

Thanks to KH6CP for this tip on the new WindCube satellite:

W9NY wrote from Chicago:

"Even though conditions were disappointing for most of the ARRL 10
Meter Contest weekend, there were sporadic openings all over the
United States from my Dune Acres location and for a few minutes at a
time signals from both the Colorado and California areas were very
strong. I also worked a number of stations in South America, but
only Puerto Rico in the Caribbean.

"On Sunday 12/19/21 10 meters really opened up for a while. I first
heard a W6 beacon in the morning coming in S9 and not a signal on
the band.  After one CQ at 28.420 I started a long string of
contacts in the late morning, and again mid-afternoon. Some West
coast stations running just 100 watts to dipoles were coming in 20
over S9 - just like the good old days.

"Made some contacts on 12 meters too. I heard NOTHING on 6 meters.

"I am looking forward to 10 meters using my MFJ loop from Miami
Beach the 1st 3 months of 2022."

KA3JAW monitors 11 meters for sporadic-E. On December 23 he wrote:

"Wednesday, December 22, 2021 there was a six-hour multi-hop
transatlantic sporadic-E event into western Europe on the 11 meter
band from 1326-1929 UTC.

"Solar flux index hit its highest point in the current solar cycle
at 140. This was due to 9 sunspot groups; 2907, 2908, 2909, 2911,
2912, 2915, 2916, 2917, and 2918."

He also wrote:

"Sunday, December 19, 2021 was a crazy eight hour single and
multi-hop sporadic-E day on the 11 meter band from 11:23 AM till
7:37 PM EST; 1623 UTC December 19th - 0037 UTC December 20th.

"During noontime, western Canada prairie provinces plus US west
coast stations were rolling into the US northeast region.

"From 5:22 PM to 6:20 PM Es conditions were deteriorating with
increased background noise conditions until the last station from
Golden Valley, Arizona was heard at 7:37 PM.

"Seems that the secondary sporadic-E winter season has begun."

On December 19, Steve Sacco (who did not give a call sign) wrote,
regarding 10 meters:

"I've never seen so many KL7s on at once.  So far, have worked two,
plus VE8CK and VY1FC.

"PSKR showing the band open from my location to Europe and KL7 and
JA and VK at 2215 UTC on 12/19/2021. JA3REX worked at 2217 UTC.

"If only this happened LAST weekend!"

N0JK wrote:

"I was on 6M MSK144 the morning of December 14 at the peak of the
Geminids Meteor shower. 50.260 MHz was busy.  Worked WI9WI, WG0G and
KF0Y in rare grid DN92 around 1400 UTC. All random contacts.

"Also checked 50.245 for W5A (EL15). Some flickers on the screen,
but no decodes."

W8TJM of Liberty Lake, Washington commented on his December 19
activity on 15 meters:

"As soon as I got my 15 meter half-wave vertical antenna up at my
low-noise site at 1915 UTC, I worked OH6RM in Finland. He was S5-S7
with very little QSB and we had a solid 25 minute QSO and then I
listened to his contacts off and on for another hour. I also had an
enjoyable contact with Per, SM2LIY at 1950 UTC and he was also
S5-S7, but had a very fast flutter on his signal that was
consistent. I heard no European stations."

Carl, K9LA commented:

"The paths that Toivo and Per commented on can be two different
mechanisms depending on where the US station is. I wrote about this
(called the Santa Claus Polar Path) in my monthly column on my
website back in 2014." .

Dr. Tamitha Skov, WX6SWW has a new forecast on December 23 with a
video lasting 96 minutes:

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 December 16 through 22, 2021 were 127, 119, 117,
109, 115, 147, and 137, with a mean of 124.4. 10.7 cm flux was
117.9, 120.9, 121.3, 115.3, 122.7, 136.6, and 140.4, with a mean of
125. Estimated planetary A indices were 8, 3, 4, 12, 16, 10, and 11,
with a mean of 9.1. Middle latitude A index was 5, 2, 2, 8, 13, 7,
and 8, with a mean of 6.4.


Instragram     Facebook     Twitter     YouTube     LinkedIn