Register Account

Login Help

ARRL Propagation Bulletin ARLP028 (2016)

ARLP028 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 28  ARLP028
From Tad Cook, K7RA
Seattle, WA  July 8, 2016
To all radio amateurs 

ARLP028 Propagation de K7RA

The recent zero-sunspot period (June 23 through July 4) ended with
the appearance of a single sunspot group (2560) on Tuesday, July 5.
Sunspot numbers were 23, 11 and 25 respectively on July 5-7. See for images of this region.

Compared to the previous week, average daily sunspot number rose
from 0 to 4.9. Average daily solar flux declined from 75.6 to 73.1.
Average planetary A index dropped from 9 to 6.7 and average
mid-latitude A index declined from 9.1 to 8.3.

Predicted solar flux shows a rising trend for the next few days,
with flux values from USAF/NOAA at 84 and 85 on July 8-9, 86 on July
10-14, 80 on July 15, 74 on July 16, 72 on July 17-30, 74 on July 31
through August 12, and 72 on August 13 and beyond.

Predicted planetary A index is 15, 10, 8 and 15 on July 8-11, then
12, 8, 5 and 8 July 12-15, 5 on July 16-18, then 15, 12, 10, 8, and
10 on July 19-23, 5 on July 24-27, then 8 and 5 on July 28-29, 10 on
July 30-31, 5 on August 1-3, then 12, 10, 8 and 18 on August 4-7,
then 12, 8, 10 and 8 on August 8-11, and 5 on August 12-14.

A glance at the STEREO web site at can
offer clues about upcoming activity about to rotate into view from
the other (hidden) side of our Sun. I can see coming over the 90
degree eastern horizon (which counter-intuitively is on the left
side of the image) are some magnetically complex regions, which
could offer more sunspot activity. These are white areas in the
image, and I am seeing this at 0800 UTC on July 7, and at 0700 UTC
on July 8 I see it has advanced well over the horizon, and has been
numbered sunspot group 2562. The group 2560 is gone, and 2561 is now
about to transit over the western side.

The STEREO images are updated frequently (as I recall, every few
minutes) so are a good source of real time information. At 0 degrees
longitude is the area directly facing Earth, and therefore the most
geo-effective. The area directly facing us takes about 4 weeks
(about 27.5 days) to transit all the way around the Sun and again
reaches the position it is in now.

At 2352 UTC on July 6, 2016 the Space Weather Services in Australia
issued a geomagnetic warning:

"The effect of a co-rotating interaction region and a high speed
solar wind stream may raise geomagnetic activity to minor storm
levels on 7 and 8 July."

For July 7 they predict: "Quiet to active with minor storm periods
possible." For July 8: "Unsettled to minor storm."

Sure enough, the planetary A index on July 7 was 23, up from 5 on
July 6. Solar flux rose from 77.1 on July 6 to 83.3 the next day.

F.K. Janda, OK1HH sends us his geomagnetic outlook:

Geomagnetic activity forecast for the period July 8-August 3, 2016.

Geomagnetic field will be:
Quiet on July 16-17, 22, 26, August 2
Mostly quiet on July 10, 14-15, 24-25, 31, August 1
Quiet to unsettled on July 9, 12-13, 21, 27-28
Quiet to active on July 8, 18-20, 23, 29-30, August 3
Active to disturbed on July 11

Increased solar wind from coronal holes is expected on July 8, (10,)
16, 28, and 30-31.

- Parenthesis means lower probability of activity enhancement. 
- Reliability of predictions is slightly reduced.

Here is a Wikipedia entry concerning VE3CC, who developed the first
system to measure 2.8 GHz (10.7 cm) noise from the Sun, and figured
out that this could be used as a proxy for sunspot measurement. A
big advantage was the ability to measure solar activity when visual
observations of the Sun were not practical, such as when the sky is

I found the reference to Covington here:

And found that link from here:

The last time this NASA solar cycle prediction was updated was
January 12, 2016, but in this July 6 version I find no difference:

This inquiry is from a reader, WA6QBU in Santa Rose, California:

"Just finished reading your Propagation article and found it very
interesting. I too have been wondering what is going on. I am a
casual DXer with simple equipment: FTDX1200/FL2100b/40 meter
horizontal loop fed with ladder line up about 30 feet.  Over this
sunspot cycle I've worked 1344 DX stations to date and in the past
two weeks 16 stations in both Europe and the South Pacific.  Mostly
this was with no sunspots and BTW, sometimes stations were coming in
from both directions at the same time.  I'm near San Francisco
(100km north) and near the coast.  These are really the strangest
conditions I've seen.  Any comments, especially about the two
directions at the same time.  Oh, and this is always after dark here
up to midnight."

Unsure how to answer this, but I may assume that this is all on 40
meters (although his page at says he
tunes this loop over 80-10 meters and works the world with 100

I am not sure that hearing stations from opposite directions
(especially since his antenna is not directional) is unusual, but of
course only WA6QBU is familiar with normal propagation from his QTH.

I also do not know how far away these stations are, but when I run
an analysis on W6ELprop using his QTH as the midpoint between my QTH
in Washington state and Los Angeles, I can see multiple examples of
both L.A. and Seattle received at the same time in Northern

But what is encouraging is WA6QBU is happy making lots of contacts
when there are no sunspots. In fact, if you use any propagation
prediction software and enter 0 for the sunspot number, you will
discover many scenarios in which there is viable propagation.

Here is a report on Field Day in Puerto Rico, submitted by Angel
Santana-Diaz, WP3GW:

"Field Day was without sunspots but we had a great network of
stations during the weekend. More than 1,000 stations worked, just
missed Idaho, Utah, Wyoming and Hawaii. Fifteen meters was king
during the day."

He also mentioned in a later email that 20 and 40 meters were good
during the evening.

And finally, this news article from Oregon which seems to get it
right concerning sunspots (or lack of them) and future climate

I see so many articles in the media concerning sunspots which
immediately jump to the Maunder Minimum and ice age, even though a
cooler climate effect would be heavily offset by massive amounts of
carbon loaded into the atmosphere over the past couple of centuries.
That's what climatologists have been telling us for the past few

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 the ARRL
Technical Information Service web page at, For an explanation of the
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 30 through July 6 were 0, 0, 0, 0, 0, 23,
and 11, with a mean of 4.9. 10.7 cm flux was 72.9, 72, 70.9, 72.3,
73.8, 72.4, and 77.1, with a mean of 73.1. Estimated planetary A
indices were 6, 7, 9, 9, 7, 4, and 5, with a mean of 6.7. Estimated
mid-latitude A indices were 7, 9, 11, 9, 9, 6, and 7 with a mean of


Instragram     Facebook     Twitter     YouTube     LinkedIn