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ARRL Propagation Bulletin ARLP025 (2020)

ARLP025 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 25  ARLP025
From Tad Cook, K7RA
Seattle, WA  June 19, 2020
To all radio amateurs 

ARLP025 Propagation de K7RA

We just experienced a nearly two week period of sunspots appearing
every day.

It's been quite some time since we've witnessed a continuous string
of sunspot activity such as what we've experienced over the past two
weeks. Back on January 24 through February 1, 2020 were nine
consecutive days with sunspot activity, but to find any longer
period of sunspot appearances requires a look back to May 3-18 of
2019. Perhaps this is an indication we've now moved past the sunspot

You can access these older records via ftp at, .

Average daily sunspot number for this reporting week (June 11-17)
was 7.9, down from 14 over the previous seven days. Average daily
solar flux slipped from 71.3 to 70.

Planetary A index went from 5.1 to 3.9, and average middle latitude
A index changed from 6.1 to 4.9.

Predicted solar flux for the next 45 days is 70 on June 19-26, then
68 on June 27 through August 2.

Predicted planetary A index is 5, and nothing other than 5, every
day over the next 45 days, from June 19 through August 2.

Regular followers of solar flux and planetary A-index predictions
may find the forecast from June 17 amusing. None of it is correct.
See it at .
I alerted NOAA, and it was fixed in the following day's forecast.

Geomagnetic activity forecast for the period June 19 til July 14,
2020 from OK1HH.

"Geomagnetic field will be
quiet on: June 22-24, 29-30, July 1-3, 8-10
quiet to unsettled on: June 19 -21, 27-28, July 7, 11, 13-14
quiet to active on: (June 25-26, July 4-6, 12)
unsettled to active on: not predicted
active to disturbed: not predicted

"Solar wind will intensify on: June (26-30,) July 4-7

- Parenthesis means lower probability of activity enhancement.
- The predictability of changes remains lower as there are very few

Ken Brown, N4SO is enjoying using the map at as a
propagation tool.

"With the PSKreporter map set for 21 MHz, FT8 mode, call sign N4SO
with the time set for last hour, do I have propagation to China,
Japan or Taiwan between 2100 to 2200 UTC?

"The map shows that yes, I do have spots in the FT8 mode, from my CQ
and working a station a few minutes ago from a couple of stations in
China, multiple stations in Japan, and one in Taiwan, as seen on the
display map on the right side of the image. It shows a path to China
when I do not have decoding from any Chinese stations in the FT8
mode on 21.074 MHz from the software. The other spots on the PSK map
are also mine from previous transmissions."

Michael, W6MVT in Upland, California wrote, "A most amazing evening
here on the west coast, as 10 meters was open and pretty strong to
most of the country. Along with another station I had a chance to
work ten stations leapfrogging all the way to the east coast. The
bad news: I had to be reminded to be a courteous operator and not
'hog' the calling frequency. A good reminder while carried away in
the heat of the QSO moment."

I will assume he was using FT8, but this is a good time to remind
readers, when sending in reports, don't forget important details,
such as the mode you were using.

Here is an article about the Solar Orbiter:

On Monday Ken Brown, N4SO sends this report on FT8 on 15 meters:

"21.074 MHZ - Digital mode FT8.

"Early morning propagation to Asia on 21 MHZ is now consistent
with end of decoding signals averaging local time 2:30 AM (0730 UTC).
I have Japan and this Indonesia station for example:

"072600 -16  0.3 1442 ~ CQ YG9WKB PI88  Indonesia

"Also, early in the evening, local time 9 PM (0200 UTC) there is
propagation on 21 MHZ on a path to Virginia (WZ4K), Michigan (W2GLD)
extending all the way to Asiatic Russia and RV0AR, Pavel in
Sosnovoborsk, Russia.  This station was easily worked at 0248 UTC.

"024800 -16  0.1 1121 ~ N4SO RV0AR R-18"

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 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

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 June 11 through 17, 2020 were 11, 11, 11, 11,
11, 0, and 0, with a mean of 7.9. 10.7 cm flux was 71.5, 70.5, 69.4,
70.2, 70.4, 69.3, and 68.8, with a mean of 70. Estimated planetary A
indices were 4, 4, 3, 2, 4, 5, and 5, with a mean of 3.9. Middle
latitude A index was 4, 6, 4, 3, 5, 7, and 5, with a mean of 4.9.


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