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ARRL Propagation Bulletin ARLP022 (2018)

ARLP022 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 22  ARLP022
From Tad Cook, K7RA
Seattle, WA  June 1, 2018
To all radio amateurs 

ARLP022 Propagation de K7RA

On May 30 at 0005 UTC the Australian Space Forecast Centre issued a
warning: "On 1 June geomagnetic activity is expected to increase to
Active and Minor Storm levels due to arrival of the co-rotating
interaction region and high-speed solar wind streams associated with
the recurrent trans-equatorial coronal hole."

On May 31 issued this Solar Wind Alert:
"NOAA forecasters estimate a 60% chance of minor G1-class
geomagnetic storms on June 1st, increasing to 65% on June 2nd, when
a stream of high-speed solar wind is expected to reach Earth.  The
last time this gaseous stream lashed our planet's magnetic field,
almost a month ago, it sparked bright ribbons of purple light
(a.k.a. 'STEVE') seen from multiple US states. Visit today's edition
of for more information."

The Sun remained active over the past reporting week. Average daily
solar flux rose from 70.1 to 74.9, and average daily sunspot number
rose from 7.7 to 26.3. During the previous week in which the average
daily sunspot number was 7.7, the first four days had no sunspots.

New sunspot regions appeared on May 21, 23 and 24.

Predicted solar flux is 77 on June 1-3, 76, 74 and 72 on June 4-6,
70 on June 7-8, 71 on June 9, 72 on June 10-14, 70 on June 15-17, 72
on June 18-23, 73 on June 24, 72 on June 25-30, 70 on July 1-6, 72
on July 7-11, 70 on July 12-14 and 72 on July 15.

Predicted planetary A index is 25 on June 1-2, 15, 12 and 8 on June
3-5, 5 on June 6-12, 8 on June 13, 5 on June 14-18, 8 on June 19, 5
on June 20-23, 8 on June 24-25, 5 on June 26-27, then 15, 28, 15,
12, 10 and 8 on June 28 through July 3, then 5 on July 4-9, 8 on
July 10, and 5 on July 11-15.

2018 ARRL Field Day is June 23-24. Assuming the predicted numbers
above, conditions should be good for Field Day. We want to see low
geomagnetic activity, and planetary A index at 5 and 8 on Saturday
and Sunday are good indicators. During this period of low solar
activity solar flux at 72 and 73 is also good.

Ted Leaf, K6HI of Kona, Hawaii reports that he is still in operation
through the local volcanic activity, and asks, "Are there beacons
for the lower frequencies, especially now with the lower solar

I found this Wikipedia resource for HF beacons:

Of course, there are lower frequency HF resources on, but this is a bit different than showing
what you can tune in and hear without using a special weak signal

Any readers have suggestions for lower frequency HF beacons?

Note that Ted has a comment on page 56 of the June 2018 QST
regarding preamps and attenuator effects on receiver noise.

From last week:

F.K. Janda, OK1HH brings us this geomagnetic activity forecast for
the period June 1-26, 2018.

"Geomagnetic field will be: 
Quiet on June 11-12, 16-17, 20-23 
Quiet to unsettled on June 10, 18, 24-25 
Quiet to active on June 8-9 
Unsettled to active on June 3-4, 7, 13-15, 19 
Active to disturbed on June 1-2, (5-7, 26) 

"Solar wind will intensify on June 1-3, (4-8, 13-15), 16-17, (18-19,

- Parenthesis means lower probability of activity enhancement. 
- Forecasts remain less reliable."

From Dr. Tamitha Skov, the Space Weather Woman:

"What's Old is New Again

"Dear Tad,

"I am still smiling at the huge response I got to a post I put up on
Twitter this week. A newbie to our Space Weather community dared to
talk about amateur radio as if it were an outdated hobby-- whoops,
bad idea. I gently educated him. In doing so, I roused many radio
amateurs and emergency communicators, who added their own comments
and talked about their own personal experiences in the field. It was
very gratifying. What I hadn't expected, however, was the strong
interest in the concept that amateur radio will be critical to
establishing over-the-horizon radio communications on planets like
Mars in the near future.

"This idea brings me back to how we managed to communicate over long
distances many decades before we had satellites, internet or
cellular networks. In terms of wireless communications on Earth, we
were very much in the same place back in the early 1900s that we
find ourselves in now when we think about colonizing Mars. Yet few
people realize that despite all our advanced technology, we can't
bring a cell phone to Mars. We will need to fall back on our 'old
ways' of doing things when it comes to communicating on other
planets. Isn't it funny how 'old' things become 'new' again?

"Speaking of, this week brings us a new chance for a decent solar
storm. Strangely though, the source of this storm is an old coronal
hole that gave us a moderate level solar storm about a month ago.
This old hole has survived its backside passage on the Sun and has
now returned, with the new promise of bringing aurora views down to
mid-latitudes again. Isn't it funny, what was old has become new
again, in more ways than one!

"Cheers, Tamitha"

Dr. Skov's latest video report:

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
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 24 through 30, 2018 were 39, 32, 26, 27, 20,
22, and 18, with a mean of 26.3. 10.7 cm flux was 73.7, 75.7, 72.9,
74.6, 76.9, 74.9, and 75.3, with a mean of 74.9. Estimated planetary
A indices were 4, 3, 4, 4, 4, 4, and 4, with a mean of 3.9.
Estimated mid-latitude A indices were 5, 4, 5, 5, 4, 5, and 5, with
a mean of 4.7.


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