ARRL Propagation Bulletin ARLP027 (2008)

ARLP027 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 27  ARLP027
From Tad Cook, K7RA
Seattle, WA  June 27, 2008
To all radio amateurs 

ARLP027 Propagation de K7RA

Recent days graced by sunspots were short lived.  June 10 through
June 13 saw a single sunspot group, followed by two days with no
spots, then a week of spots from June 16-22.  During that week the
sunspot number was 11 every day, the lowest non-zero sunspot number.
The four days since have had no spots at all.  You can see the
sunspot numbers for the last calendar quarter at,  This current
quarter data is only available on the net through June 30.  July 1
begins a new quarter.

This weekend is ARRL Field Day, and while there are no sunspots,
sporadic E skip is a possibility, and conditions should be quiet,
meaning no geomagnetic disturbance is expected.  Predicted planetary
A index for June 27 to July 3 is predicted at 10, 8, 5, 5, 5, 5 and
5.  Geophysical Institute Prague expects unsettled conditions June
27-28, quiet to unsettled June 29, and quiet June 30 to July 3.

Ken Standard, AD5XJ of Houma, Louisiana wrote, "I have been tracking
the NOAA dynamic indicators available at, While I see that if
everything is in the green areas that is better than when they are
in the yellow or red areas. My problem is figuring out what
indication each has for HF propagation specifically. The available
data on these indicators is scarce and ambiguous at best. Can you
enlighten a student of El Sol?"

The first figure, the Magnetic Field Bz component, relates to the
IMF, or Interplanetary Magnetic Field, which we've mentioned in past
bulletins.  When it is pointing north relative to earth, this
provides a kind of shield against solar wind, and earth is less
likely to experience geomagnetic activity.  When it points south,
the earth is vulnerable.  The scale in this figure is marked green
at one of the scale, indicating the most protection, and red at the
other end, to represent the greater likelihood of geomagnetic

The next two figures, Speed and Dynamic Pressure, express the speed
and pressure currently from solar wind.  Similarly, the scales run
from green to red signifying their relationship to geomagnetic

We've had news of recent e-layer propagation on 6 and 10 meters, and
Tom Scorr, AD5FD of Shertz, Texas wrote to us about 2 meter sporadic
e and an opening Sunday morning of the recent VHF contest.  Running
100 watts to a dual band ground plane on SSB, he worked three grids
in Minnesota and two in Wisconsin.  He is in EL09, and said this
went on four an hour with very loud signals.  One station was 20 db
over S9.

Neal Sulmeyer, K4EA of Canton, Georgia said on June 13 from
2300-2345z he worked 17 JA stations on 6 meters from EM74.  He
wrote, "My best guess is that this was multi-hop Es as there was no
aurora and the SFI was in the mid sixties.  I have asked several of
the long time 6M operators in the area and there is agreement that
this is the first time that JA's have been worked from north Georgia
on Es."

Todd Phillips, N4QWZ of Greenbrier, Tennessee had a blast on 2
meters in the recent VHF contest.  He is in EM66ok, and says WA7JTM
was his longest distance 2 meter contact, at 1278 miles.  He worked
KB0HH EM06 on both 144 and 432 MHz via tropo, at 685 miles.  He
wrote, "To top the day off, on 6 meters as I was working a pile of
1s and 2s, EA8BPX IL18 called me (4034 miles). The best JUNE CONTEST

Pat Dyer, WA5IYX of San Antonio, Texas sent a link to audio of
National Weather Service station KXI68 on 162.45 MHz in Iowa, 1011
miles away.  This was on Sunday morning during the VHF contest, and
you can hear the audio file at,  He used an 11 element 6
meter Yagi mounted six feet above ground, and worked mostly into
Iowa and Minnesota.  You can listen to him at, working Japan on 6 meter

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 a detailed
explanation of the numbers used in this bulletin, see An archive of past
propagation bulletins is at Monthly
propagation charts between four USA regions and twelve overseas
locations are at

Instructions for starting or ending email distribution of this
bulletin are at

Sunspot numbers for June 19 through 25 were 11, 11, 11, 11, 0, 0,
and 0 with a mean of 6.3.  10.7 cm flux was 64.9, 65.2, 64.8, 65.4,
65.3, 65.8, and 65.9 with a mean of 65.3.  Estimated planetary A
indices were 6, 11, 5, 4, 3, 4 and 12 with a mean of 6.4.  Estimated
mid-latitude A indices were 5, 8, 4, 2, 2, 3 and 10 with a mean of