Register Account

Login Help

ARRL Propagation Bulletin ARLP022 (2011)

ARLP022 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 22  ARLP022
From Tad Cook, K7RA
Seattle, WA  June 3, 2011
To all radio amateurs 

ARLP022 Propagation de K7RA

Sunspot activity is up sharply this week, with the average daily
sunspot number increasing over 55 points to 89.9.  Average solar
flux rose nearly 20 points to 103.1.

The latest forecast shows solar flux at 115 on June 3, 110 on June
4-6, 105 on June 7-8, 100 on June 9-14, rising to 105 on June 15 and
110 on June 16-26.  Planetary A index is predicted to be 12, 20, 15
and 10 on June 3-6, 5 on June 7-10, 8 on June 11-13 and 5 on June
14-21.  The next period of high geomagnetic activity is projected
for Jun 22-27, at 12, 22, 18, 18, 15 and 8. Note that ARRL Field Day
for 2011 is June 25-26, which should be just after the predicted
peak in geomagnetic activity, currently predicted for June 23.

Geophysical Institute Prague sees unsettled to active conditions
June 3-4, unsettled June 5, quiet conditions June 6-7, and quiet to
unsettled June 8-9.

With the passing of May, we can look at some moving averages of
sunspot numbers.

74.4 was the average daily sunspot number for the latest 3-month
period, March through May, centered on April.  The three month
moving averages centered on May 2010 through April 2011 were 16.4,
20.4, 23.2, 28.9, 33, 35.6, 31, 30.1, 35.3, 55.7, 72.3 and 74.4.

The average sunspot number for May was 61.5, down somewhat from
March and April.  The monthly averages of daily sunspot numbers for
January through May 2011 were 32.3, 53.5, 81.1, 80.8 and 61.5.

Currently there are eight sunspot groups visible.  You can see a
daily sunspot update at,

Check for
an article titled "Mysterious Origins of Dark Sunspots Explained."
The journal Science has an abstract for the article mentioned in the
Dark Sunspots piece at,
Often with an account at your local library you can log in and read
the full text of the article.

Another article similar to the "Dark Sunspots" article is on the

Don Tucker, W7WLL who lives in Yachats (pronounced YAH-HOTS) on the
Oregon coast, writes "The bands, particularly 20, have been so hot
that I worked WAC and probably could'a worked DXCC in one 24 hour
period if I'd tried!!  Antennas, antennas, antennas. Can't hear 'em,
can't work 'em."

Check out Don's station and antennas at

Bob Elek, W3HKK of Johnstown, Ohio reminds us of the upcoming ARRL
June VHF QSO Party, which runs from 1800 UTC June 11 through 0259
UTC June 13.  See for
details.  Bob writes - concerning 6 meters - "My own observation
over 2010 and 2011 is that during last year's Es season there were
many more broad strong openings 1000 miles out, and therefore more
double/triple hop openings than I've heard this year. In 2011, I
often hear a handful of signals, often up and down into the noise,
and that's it. How much of this is based on antenna height, and very
low angle of radiation I have no idea. But it just seems like 6
meters has been a far tougher Es band this year."

Jon Jones, N0JK of Lawrence, Kansas writes: "On Sunday May 22, 6
meters opened via multi-hop Es to the Caribbean most of the day. I
worked FG5FR at 1928 UTC on 50.105 MHz. Franz was a solid 559 on my
dipole. Heard numerous KP4s, 9Y4D and P43A. FJ/OS1T was on earlier
and gave many a new country on 6M."

Later Jon wrote: "I heard K0ZN EM28 working K0SBV DM42 on May 29.
K0ZN is in DeSoto, about 15 miles from Lawrence."

Kent Doucy, N0IRM of Galena, Missouri had a nice 15 meter opening.
He writes, "At 0454 UTC on May 31, 2011 I found 5W1SA from Samoa
calling CQ on 21.020 with a great 579 signal. A little later at 0528
UTC I was also able to work Brad FO/N6JA on Marquesas Island on
21.018, he was a little harder copy with a 519 signal. Nothing else
was heard after that but it was a nice short lived late 15 meter
opening to the Midwest." See Kent's antennas at .

Rudy Hanau, K2EVY of Rye, New York had some interesting comments
regarding backscatter:  "Most of us have run into HF backscatter at
one time or another.  In my experience the other station and I find
ourselves pointing our beams at some common point out of line with
the direct path between us.

"However, this incident was a bit different. On May 29 the SFI was
101 and the A index was 36. Not your most common set of conditions
and, I suspect the geomagnetic activity associated with the high A
is involved. Twenty meters was very sparsely populated and K6ZA's S9
signal stood out. My QTH is Rye Brook, NY (FN31) and Barry is in
Walnut Grove, CA (CM87). His bearing should have been 280 degrees,
just a bit north of West for me, and indeed it was. He was just
finishing another QSO and I called him. He told me he had been
working KL7 and was looking North! I swung North and lost him. He
looked East and lost me. We were both S9 or better when our antennas
were about 90 degrees to one another.  We scratched our heads and
looked every which way for another path but there was none.

"I signed after about 30 minutes and Barry went on to work another
station (more about that later). When working backscatter we usually
think of some far off reflecting area such as aurora over Alaska or
the pole.  In mulling this contact over the only explanation I can
offer is that the reflecting area was very near Walnut Grove and was
omnidirectional, like a vertical.  If it was 50 or 100 miles north
of Barry it would be indistinguishable from Barry's QTH for me
whereas Barry would have to point north to see it.

"Barry described his next contact as follows: 'After our QSO I was
called by a Laughlin, Nevada station SE of me, also same scenario.
He was seeing me at normal NW direction. He was strongest to the
North. Then, during the 30 min contact, I found I could move the
beam toward the east with no change in strength and then he began to
peak more toward him and less to the North. By the end, he was 40
over at SE, and no propagation to the north at all."'

There is a slightly revised solar cycle prediction from NASA at This month it says
"Three consecutive months with average daily sunspot numbers above
40 has raised the predicted maximum above the 64.2 for the Cycle 14
maximum in 1907." Last month it said "Two consecutive months with
average daily sunspot numbers in the 50s has raised the predicted
maximum above the 64.2 for the Cycle 14 maximum in 1907."

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 Find more good
information and tutorials on propagation 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 26 through June 1 were 40, 65, 91, 89, 105,
132, and 107, with a mean of 89.9. 10.7 cm flux was 82.7, 89.9, 101,
110.8, 111.9, 112, and 113.6, with a mean of 103.1. Estimated
planetary A indices were 7, 11, 40, 32, 9, 13, and 12, with a mean
of 17.7. Estimated mid-latitude A indices were 4, 7, 32, 17, 7, 10,
and 9, with a mean of 12.3.


Instragram     Facebook     Twitter     YouTube     LinkedIn