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ARRL Propagation Bulletin ARLP031 (2018)

ARLP031 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 31  ARLP031
From Tad Cook, K7RA
Seattle, WA  August 3, 2018
To all radio amateurs 

ARLP031 Propagation de K7RA

After six days with no visible sunspots, a new one appeared on
Wednesday, August, 1, with a daily sunspot number of 11. As there
was also only one day with a sunspot (also 11) in the previous week,
average daily sunspot number for this week was unchanged at 1.6. The
new sunspot is small and was given the number AR2717 on Thursday,
when the sunspot number again was 11.

Average daily solar flux was down from 68.4 to 68. Average daily
planetary A index decreased from 8.1 to 5, while average daily
mid-latitude A index went from 8 to 5.1.

According to an August 2 forecast prepared by the US Air Force,
predicted solar flux is expected to be 70 on August 3, 72 on August
4 to 9, 71 on August 10, 70 on August 11 to 17, 68 on August 18 to
20, 66 on August 21 to 23, 68 on August 24 through September 6, 70
on September 7 to 13, and 68 on September 14 to 16.

Predicted planetary A index is 8 on August 3, 10 on August 4 and 5,
6 on August 6, 8 on August 7 and 8, 5 on August 9 to 11, 8 on August
12 and 13, 5 on August 14 and 15, then 8 and 12 on August 16 and 17,
5 on August 18 and 19, 20 and 12 on August 20 and 21, 5 on August 22
through September 1, then 10 and 8 on September 2 and 3, 5 on
September 4 and 7, 8 on September 8 and 9, 5 on September 10 and 11,
8 and 12 on September 12 and 13, 5 on September 14 and 15 and 20 on
September 16.

Reader Max White, M0VNG of Worcester, England sent this about
experiments with ionospheric sounding over 50 years ago, both below
and above the ionosphere:

Jeff, N8II wrote:

"There has been sporadic E to somewhere every day on 10M in the past
week, but today, August 2nd, was absolutely amazing. It all started
working MW0EDX, Wales on 15M CW via sporadic E with a good signal at
1815Z. Then I called CQ on 15 CW and DL4KCA answered. He was 589 on
15 CW with a 3 element StepIR; we tried 12M and he was 549 (my
antenna 2 el vs 5 el Yagi on 15 and 10), and 549 on 10 CW.

I worked Fred F5NBX, a 10 CW regular just after Joe and tried more
CQ's on 10 and 15 to no avail. Then, the big surprise happened at
1905Z when I heard Vlad, R2KW 549 on 10 CW in Kaliningrad in a QSO;
one try and I was in his log. Then the following stations answered
my CW CQ's: UA3EDQ, RZ3AK, and RQ3A Moscow, RU2K Kaliningrad, and
UX7IB and UX2VA in Ukraine all S 2-3.

Then still in 1900Z hour, I had a few western EU stations call on CW
from Germany, France, PA0KBN Netherlands (new DXCC band slot since
1/17) and ON4BCN Belgium (new slot). I then found OH0Z Aland Is. who
was 549 (new slot)! This was followed by 9A2018CRO Croatia, and more
from Italy, Germany, France and England.

The 2000Z hour was relatively quiet with Hristo LZ2HR found at 2010Z
and Q5 copy for the next 2 hours! Also on 10 CW I worked one each
Spain, Italy, and England in the hour. I was about to QRT for dinner
at 2100Z when a few new stations appeared. On SSB Ian MM0TFU called
in very weak followed by CW QSO's with OH0Z now 559, Germany, Spain,
and Robert S50R Slovenia. Then at 2122-2151Z conditions markedly
improved and on SSB I ran 30 European stations all in Germany,
England, Spain, France, Italy, Netherlands, Belgium, and Portugal.
The last few minutes were spent chasing DX cluster spots and
spotting some stations of my own on CW working ZB2FK Gibraltar (new
slot), KL7SB/VP9 Bermuda (new slot), LZ3ZZ, TA1D Istanbul, Turkey
(new slot), and MU0FAL Guernsey at 2205Z. After a dinner break at
2246Z, the band seemed to have closed to EU, but VY2CAK on Prince
Edward Island was S9+.

In my 47 plus years of operating I had never worked Russia,
Kaliningrad, Ukraine, Aland Is., or Turkey on 10M via sporadic E
during the summer months; it was an incredible opening!" (When Jeff
says "new slot" it refers to the first time working a DXCC country
on a particular band, as he explained above.)

Jon Jones, N0JK in Lawrence, Kansas sent this on August 2: "Usually
the sporadic E season winds down in August. But so far it has been
going strong. A big E opening on 6 meters August 1 from Japan to the
southeast states, and N0LL and I had CT1HZE into Kansas August 1. On
August 2 Europe was in for hours as far west as the Mississippi
River. Why the good conditions? It has also been a great season for
NLC (noctilucent clouds). They form at 85 km altitude. The E-layer
is 90 - 160 km high. Perhaps the same upper atmosphere conditions
keeping NLC going strong may be influencing sporadic E. See"

Note that has a gallery of images devoted to NLC:

Frantisek Janda, OK1HH sent the following from Ondrejov in the Czech
Republic. See his bio on for more about him.

"Geomagnetic activity forecast for the period August 3 to 29, 2018.

Geomagnetic field will be:
Quiet on August 5, 10 and 11, 15, 23-24
Quiet to unsettled on August 14, 16, 22
Quiet to active on August 3 and 4, 6 to 9, 12, 25 to 29
Unsettled to active on August 12, 17 to 19, 21
Active to disturbed on August (13,) 20

Solar wind will intensify on August (16 to 19,) 20 to 22, 28 to 30

- Parenthesis means lower probability of activity enhancement.
- Reliability of predictions remains low."

Dr. Tamitha Skov sent this, followed by her video for this week:

"Dear Tad,

Last week I mentioned traveling was always an adventure and this
trip has been no exception. After being unable to connect to the
television in my hotel room (I tried with two separate computers), I
settled for shooting my forecast using my mobile phone camera in a
way it was never intended. The result has been an unconventional
video to say the least. I almost didn't post it, as it's not up to
my usual standards, but I figured you would forgive the
imperfections in favor of the content.

Additionally, I apologize for getting this newsletter out to you a
little late this week. Spotty internet connection while on the road
has prevented me from sending it out until today. However, being
mobile in Europe this week has given me the chance to reflect on how
deeply entrenched space exploration is in our global culture. In
fact, while in Amsterdam I came across an art installation showing
an astronaut impossibly balancing between a chair and a flower pot
(see The Joseph Klibansky installation,
called "Self-Portrait of a Dreamer," succinctly captures our
culture's dreamy fascination with space and its intersection with
objects in our more ordinary lives.

As I stared up at this massive structure, the symbolism began to
sink in. I realized we are a lot like that dreamy astronaut,
striving to blend our understanding of space with its impacts on our
everyday world. I also realized that just like the astronaut, we too
will one day soon strike a perfect balance.

This week's forecast brings us an Earth-directed stealthy solar
storm followed by a small pocket of fast wind that will likely have
little effect, but could bring subtle aurora to high latitudes. Even
though GPS users might experience glitchy reception near aurora,
users at low latitudes should enjoy better than normal reception due
to the light impact of the storm. The Sun also has two bright
regions rotating into Earth-view this week that should help keep
amateur radio propagation near marginal levels, so there is some
good news for everyone.

Cheers, Tamitha"

For more information concerning radio propagation, see 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 July 26 through August 1, 2018 were 0, 0, 0, 0,
0, 0, and 11, with a mean of 1.6. 10.7 cm flux was 66.2, 66.6,
67.9, 68, 68.3, 68.9, and 70.2, with a mean of 68. Estimated
planetary A indices were 4, 4, 5, 5, 5, 6, and 6, with a mean of 5.
Estimated mid-latitude A indices were 6, 4, 6, 5, 5, 5, and 5, with
a mean of 5.1.


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