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ARRL Propagation Bulletin ARLP016 (2011)

ARLP016 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 16  ARLP016
From Tad Cook, K7RA
Seattle, WA  April 21, 2011
To all radio amateurs 

ARLP016 Propagation de K7RA

The bulletin is out a day early due to the Good Friday holiday
observed tomorrow.

Average daily sunspot numbers and solar flux for the week were both
higher - sunspot numbers up over three points to 93.1 - and solar
flux up by eight points to 117.2.  Geomagnetic activity was a bit
lower, with April 20 the most active day after a coronal hole on the
Sun spewed a solar wind at high speed.  The Australian government
gave an alert one day prior.  You can subscribe to those emailed
warnings at
If you are in Australia, the same service offers an HF radio
propagation course. See for details.

The same Australian service has predicted monthly smoothed sunspot
numbers and solar flux at and it
looks like they predict the peak of Cycle 24 exactly two years from
now in April 2013.

Currently there are four sunspot groups visible, and today could see
a geo-magnetic disturbance from a slow-moving coronal mass ejection.

The latest forecast from NOAA/USAF shows solar flux at 115 for April
21-24, 110 for April 25-29 and 115 again on April 30 through May 3.
Predicted planetary A index is 10 and 8 for April 21-22 and 5 on
April 23-27.  On April 28-30 the predicted planetary A index is 7,
15 and 12.

The May issue of WorldRadio Online is now available at Check out the propagation column by
K9LA on page 22, which this month concerns an unusual divergence
during the recent solar cycle when correlation between solar flux
and sunspot numbers seemed to decrease.

Mark Lunday, WD4ELG of Greensboro, North Carolina is excited about
all the recent solar activity and associated propagation.  Mark
says, "I never thought it would happen, but the sunspots are back!"

Mark notes that 10 meters is open worldwide during the day and 20
meters is open all day and night to somewhere in the world.  He
sends lists of DX worked from all over, all with simple antennas.
Check his blog at

Richard Kautz, KC2HZW of Pelham, New York is looking forward to a
good sporadic-E and F-layer propagation season on 6 meters.  He
says, "Really been enjoying the renewed sunspot activity the last
two months. This week conditions on 15 meters have been excellent.
Friday April 15 I worked HS0ZIN at 1523 with 59+ signals in both
directions. Saturday I worked VU2PAI at 1920 again with 59 signals
in both directions. Also worked JE1LET at 2330. Listened to KL7LF
for a while working a pile-up with a great 59 signal. I modeled many
of the contacts I made the last few days on W6ELPROP and while the
program predicted many of the contacts were possible, in none of the
cases did the predictions show signal strengths anywhere near what I
experienced. I am not complaining -- it been about 8 years since I
worked into South East Asia on the higher bands and it was a real

Oleh Kernytskyy, KD7WPJ of Saint George, Utah has been operating QRP
CW from mountain peaks out west.  He writes, "On April 16/17, 2011 I
activated Grandeur Peak (SOTA -W7/NU-065) - 2530 m. I was able to
make contacts with JE2RMH and 5N7M on 21 MHz with 10 w and simple
dipole. I also heard a lot of stations from Brazil on 28 MHz, but
they all worked in the contest."

Jeff, N8II of West Virginia writes on April 16, "The SFI is 129 and
the K is 1 today and you could tell it. But first back to Monday the
11th when I was lucky enough to be off from work. On 15 meters CW,
between 0018 and 0031Z BA1KW, HS0ZBS, and XV2W were logged, great DX
for us on the East Coast. Then as early as 1249Z IS0GQX was 599 on
12 meters CW. P29NI running a big IOTA EU pile-up was easily worked
on 17 meters at 1236Z and JJ0NCC answered a CQ at 1309.

"Then up on 15 meters YB0NFL was worked on SSB 59 at 1325 (quite
early) along with UA0SR, UA9QM, and YB9/DJ7XJ on 15 CW. But the
biggest surprise of the day was E21EJC at 1418, HS0ZBS, and 9M2TO on
12 meters CW! Then, I was treated to more over the pole DX on 15
meters, VU2PAI and V85TL. HS0AC was logged on 17 meters CW at 1525,
and found Kob, E21EJC there 10 minutes later. It doesn't get much
better than that here unless 10 meters opens polar which is rare.
Today the 16th started with 14 Russians from all over Asia answering
my CQ from 0033 thru 0115 along with HB9, EA5, BD0AH, and UN7PBW on
20M CW.

"At 1305Z XV2RZ was worked on 17 meters CW and P29VLR was running a
large EU pile-up and was about S3-4 here. At 1325, 12 meters was
open well to EU at 1325Z with OL2011VP 599 on 12 CW, but despite a
good EU opening with lots of Germans logged, the band never opened
to the Far East as on Monday. 10 meters started to open to EU at
1423Z with 4O3A logged 599+ 15dB, but CQs yielded no answers.  After
a run of EU on 12 meters, I returned to 10 meters SSB at 1522Z to
find HZ1DG a 57. Then I worked around the Mediterranean area on 10
meters logging Is, three IT9s, E71A, and 9H5BZ. Down on 15, the band
was open to most of Asia including due north to SE Asia logging
RL9AA on CW and on SSB 9M2GET a 59 at 1634Z running a big pile-up, I
also logged YC6NE and neighbor YB6MIX at 1702Z. It was quite a

Bud Trench, AA3B of Boyertown, Pennsylvania writes that he was on
this past weekend and the bands were very nice.  His summary:

"10M - Very nice opening to SA on both Saturday and Sunday.  Also
brief openings to southern and central Europe on both days, with
Sunday being the better of the two.

"15M - opened nicely to Europe early both mornings and stayed open
until late afternoon.  Also, a good North - South path.  This was
the best band for the weekend.

"20M - marginal on Saturday to Europe, a little better on Sunday.
The best openings were mid to late afternoon.

"40M - the band opened to Europe around 22z with decent conditions.
Signals on the North - South path were fluttery.

"80M - some loud signals from Europe around 00Z, but conditions
weren't impressive."

There was a problem with some of the web links in some versions of
last week's Propagation Forecast Bulletin ARLP015, specifically the
ones that were emailed to subscribers and the copies that appear in
the bulletin archive at I was using a
shortened link that goes through the site, and
they had some problems which deleted the links we provided. So the
first one, ending in "snys" should have gone to, the second
one, ending in "snz" should have gone to, and the
next ending in "so8j" should have linked to
Thanks to Dick Grubb, W0QM for catching this.

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 April 14 through 20 were 131, 124, 97, 67, 67,
76, and 90, with a mean of 93.1. 10.7 cm flux was 118.7, 129.4,
119.2, 114.4, 111, 110.9, and 117, with a mean of 117.2. Estimated
planetary A indices were 7, 6, 4, 5, 10, 6, and 16, with a mean of
7.7. Estimated mid-latitude A indices were 3, 3, 2, 2, 8, 4, and 11,
with a mean of 4.7.


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