ARRL Propagation Bulletin ARLP014 (2011)

ARLP014 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 14  ARLP014
From Tad Cook, K7RA
Seattle, WA  April 8, 2011
To all radio amateurs 

ARLP014 Propagation de K7RA

Our Sun is still quite active, but sunspot numbers are down this
week when compared with the week before.  Average daily sunspot
numbers were down nearly 34 points to 68.3, and average daily solar
flux declined nearly 3 points to 111.8.  Geomagnetic activity was
quite strong this week, with planetary A index on April 2 at 20, and
26 on April 6.

The latest forecast from USAF and NOAA is for lower activity than
the forecast from Wednesday, reported in the ARRL Letter.  The
latest from Thursday, April 7 has solar flux of 110, 100, 95 and 100
for April 8-11, 105 on April 12-15, then 90, 100, and 115 on April
16-18, and 125 on April 19-27.  Predicted planetary A index is 5, 5,
10 and 10 on April 8-11, and 5 on April 12-17, and 7 on April 18-20.

Geophysical Institute Prague predicts quiet conditions on April 8,
quiet to unsettled April 9, unsettled to active April 10, active
April 11, unsettled April 12, quiet to unsettled April 13, and back
to quiet on April 14.

On April 4 NASA released a new solar cycle prediction, and they say
Cycle 24 may be the smallest sunspot cycle in 200 years.  Read about
this prediction at

NOAA/SWPC Boulder has their own updated prediction, which you can
see on page 14 of the April 5 Preliminary Report and Forecast at This has hardly
changed from last month's version, at, but notice that the
predicted smoothed sunspot values for April, May and August 2011 are
each slightly higher on the new one, by one point each.  Since these
smoothed values are averaged over a year, perhaps this slight
increase is because of higher recent solar activity.

As he often does, David Moore sent in a couple of interesting and
informative links.  Click on for a video
from the Smithsonian on the Solar Dynamics Observatory and the
STEREO mission.

The second at is an article from the
Smithsonian about scientific efforts to understand our Sun.

Glenn Wyant, VA3DX of St. Catherines, Ontario sent in a report on DX
recently worked.  He writes, "On March 25 my good friend Garry VE3XN
called me on the phone at about 1125z. He claimed he had just
finished his 5 Band WAZ with a XU7ACY (Cambodia) QSO on 80 meters
CW! Although it was too late for me that day, I was there the next
day and put Peter XU7ACY in my log for a new one on 80.

"What was really neat was to work Peter again on March 28 at 1133z
for a new one on 12 meters! I also worked E21EJC (Thailand) on 12
meters at 1620z for another new one on 12. The following day (March
29) I again worked Kob E21EJC on 10 meters at 1440z, as well as
VU4PB on 12 CW at 0103z, and had to beam at 190 degrees to copy him.
I figured I was done with new band countries for awhile now, but
March 30 proved me wrong.

"At 1437z I worked VU4PB on 10 meter CW and then again at 1558z on
10 meter SSB. Both QSOs were on the traditional path at 10 degrees.

"What was strange was that VU4PB was 5x7 here at one point on SSB,
yet my friend Garry VE3XN, only 142 miles west of me and using the
same antenna as I and at the same height could not copy them at all!
Sort of like 6 meter spotlight propagation."

See a picture of Glenn and his station at,

Angel Santana, WP3GW of Trujillo Alto, Puerto Rico says, "Last week
I had an 'Arabian Night' because between 31 March/1 April UTC over a
50 minute period got to work A92GR, A41OW and 9K2OD on 20 meters,
plus heard 9Y4D work a VU3, which sounded very strong! And 1/2 an
hour later contacted the largest Island of the world: Greenland -
OX3KQ on 18.126 MHz. And incredibly got to work YB0NFL on 10 meters
at 1530 UTC (11:30 am local) Saturday 2nd!"

This was all on SSB. See an interesting photo of Angel in his
station at,

Dan Eskenazi, K7SS of Seattle notes that just before the recent
improved propagation conditions, his antenna blew down in a
windstorm.  Now some of his more superstitious ham friends are
begging him not to put it back up.

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 March 31 through April 6 were 76, 62, 66, 70,
83, 65, and 56, with a mean of 68.3. 10.7 cm flux was 113.3, 108.9,
107.5, 114, 112.7, 109.2, and 117.1, with a mean of 111.8. Estimated
planetary A indices were 3, 13, 20, 16, 8, 7, and 26, with a mean of
13.3. Estimated mid-latitude A indices were 2, 9, 13, 11, 6, 4, and
16, with a mean of 8.7.