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ARRL Propagation Bulletin ARLP023 (2018)

ARLP023 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 23  ARLP023
From Tad Cook, K7RA
Seattle, WA  June 8, 2018
To all radio amateurs 

ARLP023 Propagation de K7RA

Sunspots vanished again after appearing on every day, from May 21
through June 4.  Average daily sunspot numbers this week (May 31
through June 6) dropped from 26.3 to 12.9.

Average daily solar flux declined from 74.9 to 73.2.  Average
planetary A index increased from 3.9 to 11.7 while average
mid-latitude A index increased from 4.7 to 10.4.

Predicted solar flux is 69 on June 8 to 10, 70 on June 11 to 14, 72
on June 15 to 17, 74 on June 18 to 23, 72 on June 24 to 30, 73 and
72 on July 1 and 2, 70 on July 3 to 7, 72 on July 8 to 14, 74 on
July 15 to 20 and 72 on July 21 and 22.

Predicted planetary A index is 5 on June 8 to 12, 8 on June 13, 5 on
June 14 to 18, 8 on June 19, 5 on June 20 to 26, then 15, 28 and 18
on June 27 to 29, 10 on June 30 through July 1, 8 on July 2, 5 on
July 3 to 9, 8 on July 10, 5 on July 11 to 15, 8 on July 16, and 5
on July 17 to 22.

Summer solstice in the Northern Hemisphere is coming up in less than
two weeks, on Thursday, June 21, just before ARRL Field Day weekend.
Around this time of year we may see sporadic-E propagation on ten
meters, and sometimes on six meters.

Check this site devoted to ten meter sporadic-E:

June 23 and 24 is Field Day weekend.  Predicted solar flux of 74 and
72 looks promising, and the planetary A index prediction of 5 for
both days is excellent.  Previously the planetary A index was
predicted at 8 for Sunday, and 5 is better.

Bill Mader, K8TE, president of the Albuquerque DX Association wrote:

"I hope you and Dr. Skov can educate folks about HF communications
on the planet Mars.  Although Mars' atmosphere is approximately 0.6
per cent of Earth's,

there are sufficient atoms to provide an ionosphere according to
some scientists (see

However, reading this paper, it's obvious the authors do not have a
lot of experience with the subject since they state the Mars
ionosphere 'reflects' radio signals, rather than refracts them.

Long ago, I gave a presentation to a middle school class on this
very subject.  This is before the scientific community knew about
Mars' complicated atmosphere, much less its ionosphere.  I suggest
satellite communications would be necessary between explorers on
Mars' surface.  It may well be you will eventually need to provide
HF propagation predictions for hams on Mars."

VK5EEE wrote, regarding a recent inquiry on HF beacons:

"Beacons on bands other than 10m on HF (28200 to 28300 kHz) are
discouraged by the IARU, however, there are a few exceptions that
have been approved (and many unapproved beacons).

The most famous and useful is DK0WCY.  The German website (with a
few pages in English) has a wealth of information.  I have also
corresponded with DDK9, the German RTTY WX station on 30m and
obtained information about that station too.  To make it easy for
hams, I have put together pages that make it easy to find what you
need about these.  Please take a look: and

A very fun beacon is IY4M that is licensed just below the 10m
exclusive beacon band (28200 to 28300) on 28195, and also on 12m.
It is extremely hard to find information about this beacon, which is
sad, as it is an amazing work.

You can QSO with the beacon in CW and it is very friendly and
upbeat, you give it various commands, such as to speed up, slow
down, send this or that info, etc.  I used to love having regular
QSOs with it from Europe especially during Sporadic E seasons.

All best wishes,

73 de Lou VK5EEE"

This is from George Ockwell, K7HBN:

"Perhaps it occurred too late in the reporting period, but I'm
surprised you didn't receive any comments on the exceptional
conditions during the WPX CW Contest.  Here in Western Washington 20
meters was open to somewhere the full 48 hour period.  The SFI was
74 to 75 with the A Index 4 to 5 and the K Index 0 to 1.  15 meters
was open to South America with some JA as well.  Brief openings also
happened on 10 meters."

That was last weekend on May 26 and 27.  See

Here is a propagation resource for the upcoming Baker Island

Other resources from K6TU:

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 May 31 through June 6, 2018 were 21, 22, 20, 16,
11, 0, and 0, with a mean of 12.9.  10.7 cm flux was 76.8, 74.8,
74.4, 73.6, 70.5, 71.3, and 71.1, with a mean of 73.2.  Estimated
planetary A indices were 12, 26, 17, 9, 5, 6, and 7, with a mean of
11.7.  Estimated mid-latitude A indices were 11, 19, 14, 9, 5, 6,
and 9, with a mean of 10.4.


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