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ARRL Propagation Bulletin ARLP020 (2020)

ARLP020 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 20  ARLP020
From Tad Cook, K7RA
Seattle, WA  May 16, 2020
To all radio amateurs 

ARLP020 Propagation de K7RA

No sunspots appeared last week. The previous seven days had only one
big sunspot group on one day, with a sunspot number of 35. Over the
seven day period this averaged out to a sunspot number of 5, so
average daily sunspot numbers declined from 5 to 0 this week.

Average daily solar flux also declined, by one point from 69.5 to

Geomagnetic indicators were quiet, with average daily planetary A
index declining from 5.1 to 4.1, and mid-latitude A index from 5 to
4.7. reports that the percentage of days with no
sunspots so far in 2020 (76%) is very close to 2019 (77%).

Every day I look at STEREO to see if
there are any hints of activity over the horizon. Each 30 degree
division on that display represents about 55 hours, and currently on
May 14 I see a bright possibly active area about 30 degrees over the
solar horizon.

Predicted solar flux is 68 on May 15 to 21, 69 on May 22, 70 on May
23 to 31, 68 on June 1 to 13, 70 on June 14 to 27 and 68 on June 28.

Predicted planetary A index is 5 on May 15 to 18, 8 on May 19 and
20, 5 on May 21 to June 8, 8 on June 9 and 10, 5 on June 11 to 13,
then 10 and 8 on June 14 and 15, and 5 on June 16 to 28.

Geomagnetic activity forecast for the period May 15 til June 9, 2020
from F.K. Janda, OK1HH.

"Geomagnetic field will be
quiet on: May 26, June 2 to 5
quiet to unsettled on: May 16, 25, 27 to 31
quiet to active on: (May 15, 20 to 22, 24, June 1, 6 to 8)
unsettled to active on: (May 17 to 19, 23)
active to disturbed: no disturbances predicted

Solar wind will intensify on: May (18 to 21, 23,) 24, June (6 and 7)

- Parenthesis means lower probability of activity enhancement.
- The predictability of changes remains lower as there are no

I've noticed recently that even with very little sunspot activity,
there is plenty of activity on the air. Checking FT8 communications
on I can see lots of weak
signal communication over marginal paths, even on 12, 10 and 6
meters. I also get reports from readers, and see reports on a local
DXer email list, and everyone seems more active of late.

I suspect much of this activity is related to the COVID-19 pandemic,
and the great number of operators isolating at home.

The May 7 ARRL Eclectic Tech podcast (listen at features a story (starting at minute 10:57)
about a medical research project using distributed computing
employing idle microprocessor cycles in volunteer's personal
computers to aid in medical research. Called Folding at Home
( participants can form
teams to do the work, and keep score. It has recently been
re-positioned to aid research on COVID-19.

Twenty years ago I started a folding team, dedicated to the memory
of the former holder of my call sign, K7RA. You can view the stats
on our team at If you
can join us, download the software from
and during installation please dedicate your work to team number

I was aware of the Carrington Event (see,
the huge solar storm of 1859, but there was another big one, 99
years ago this week, that also set fire to telegraph offices and
caused general mayhem. See and

Ken Brown, N4SO (EM50) in Grand Bay, Alabama reports unusual 15
meter propagation at an odd time, after midnight where he is. On May
11, using FT8 he heard VE7SKY (CN89) at 0602 UTC and then 8C2WFH,
(OI53) in Indonesia at 0649 UTC.

Mark Bell, K3MSB of Airville, Pennsylvania wrote on May 8: "10M Has
been open the past few days. I've worked stations in TX and CA on
Thursday May 7th, and stations in MN and WA on May 8th, using CW and
100 watts. It was classic Es propagation. I had no RBN reports for
the 7th, but very nice ones on the 8th. Several other stations were
calling me on the 8th but I was unable to work them."

On May 11 Mark wrote:

"Here's an update to my update. Between May 7-10, I worked 10 states
on 10M CW. Single hop sporadic-E into TX, MN, FL, TN, MO, LA, and WI
and double hop into CA, WA and ID, all CW. I heard quite a few more
stations calling me but I was unable to work them."

Marked mentioned RBN. More info:

Jon Jones, N0JK wrote from Kansas: "Es May 11. Caught J68HZ (St.
Lucia) on 50.313 MHz at 2345z on 2x Es. Note the report, -24 dB! So
far no major openings like on April 15, but overall Es season
starting to pick up."

Danny Miller, KB8W wrote: "There was a nice Es opening on 6 meters
during the afternoon and evening of May 8 from my UP of Michigan QTH
(EN57) to Idaho, western Montana, Alberta and Saskatchewan. Es is
common in the central USA during the summer months but it is very
early to have it happen so far north in early May, the Es cloud
appeared to be over North and South Dakota.

I worked 12 stations over about ten hours, using FT8 on 50.313 MHz.
I run only 50 W to a 5 element Yagi on 6 meters, so it is great to
have some extended propagation to help me work those western grid

K0ZN wrote from De Soto, Kansas: "May 7th had some exceptional HF
conditions. I have not heard things this good in several years. What
got my attention was when I turned the radio on about 11 PM, WWV was
pounding in at 35 db over S-9 on 10 and 15 MHz and S-9 on 20 and S-7
on 25 MHz here in Kansas City; that is only a 550 mile path, quite
short for 20 and 25 MHz at 11 PM CST! I got on 10M and heard strong
west coast signals and worked a KH6 running 30 W to a vertical with
good signals both ways. The impressive thing was hearing a UA6 who
was S-9 working a Polish station! 30 M was clearly wide open to a
large part of the world... at midnight CST. One can only hope this
is an omen of better things coming on HF."

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

For more information concerning radio propagation, see and the ARRL Technical Information
Service 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

Monthly propagation charts between four USA regions and twelve
overseas locations are at

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

Sunspot numbers for May 7 through 13, 2020 were 0, 0, 0, 0, 0, 0,
and 0, with a mean of 0.  10.7 cm flux was 68.7, 67.9, 71, 67.9,
66.2, 68.9, and 68.8, with a mean of 68.5.  Estimated planetary A
indices were 4, 4, 3, 5, 5, 4, and 4, with a mean of 4.1.  Middle
latitude A index was 5, 4, 3, 5, 7, 5, and 4, with a mean of 4.7.