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ARRL Propagation Bulletin ARLP031 (2008)

ARLP031 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 31  ARLP031
From Tad Cook, K7RA
Seattle, WA  July 25, 2008
To all radio amateurs 

ARLP031 Propagation de K7RA

For several days over the past week we saw a couple of sunspots, but
just like other recent dying cycle 23 spots, they faded quickly.
This group was number 1000, and lasted from July 18-20.  No sign of
cycle 24 in recent memory, just a couple of false starts.

The autumnal equinox, the beginning of the fall season, is less than
60 days from now.  I would like to suppose that cycle 24 will be in
full swing by then, but we have no way of knowing.

We are still getting regular reports from readers about the
continued sporadic-E activity on six and ten meters.

Going back a few weeks, Mark Lunday, WD4ELG of Hillsborough, North
Carolina commented ''Amazing the stuff that happens at the sunspot
lulls.  Actually gives calmer conditions under which to observe
phenomenon like gray line prop without the geomag disturbances''.
That's true, and I can recall a couple of years when there was a
fair amount of sunspot activity, but month after month we witnessed
severe geomagnetic storms, making HF bands nearly useless,
especially at higher latitudes.

Back on July 7 at 0210z Mark accidentally switched to 12 meters and
heard FO5RH (French Polynesia) calling CQ on CW.  This was 90
minutes after Mark's local sunset.  They exchanged S5 signal

Two days later on July 9 at 2335z, George Pituras, W8KQE of North
Olmsted, Ohio (EN91) worked CT9HZE (Portugal) on 6 meters CW, when
George was running 100 watts into an omnidirectional loop antenna.
The next day he worked Utah on six, completing 48 states worked
using the same loop.  He hopes someday to confirm Alaska and Hawaii
on six.  He signs his email, ''Six meters forever!''

Doug Phillips, W7RDP of Sammamish, Washington reports that on July
12 he and a group known as PNW QRP used the call K7S for an annual
outing to the Bowman Bay area of Deception Pass State Park on
Fidalgo Island. (48.416 deg N, 122.65 deg W, see  In addition to HF, Rod Johnson, WE7X
ran 3 watts on 6 meter CW and SSB into a halo antenna 15 feet above
his picnic table, and worked several Southern California stations in
the Los Angeles and East Mojave Desert area.

Jim Henderson, KF7E of Queen Creek, Arizona sends us some
provocative observations regarding the double solar cycle peaks and
possible double minima, mentioned by W7TJ in ARLP029.

Jim writes, ''The double peak was prominent on the last two cycle
maxima.  Last minimum showed slight double as well.  But I have
stated since about mid-2005 that the coming cycle will start after a
protracted, double minimum (as in a dip, slight but obvious
increase, then dip).

(Here he references

''Of interest to me (besides the admonition that this minimum is not
a record low) is the possible support of Mausumi Dikpati, et al's,
forecast that this cycle will start late and be ''30-50% more
intense' that is revealed in the plots for the 1933 minimum at the
end of this piece.

''While we need 200+ days of spotless sun to equal 1933, a comparison
of the peak of Cycle 16 (approx 80) to that of Cycle 17 (approx 120)
shows that it was almost exactly 50% higher.

''Protracted low, followed by a bigger maximum.

''A bit of good news?

''It doesn't prove anything, but I am encouraged to continue placing
my bet on Ms Dikpati....

''If I am wrong about Dikpati's forecast and we go into an extended
period of low cycles, I will be selling my 10/12/15m antennas and
installing a 160m Yagi. :-)''

(Dikpati is reference to a 2006 prediction for a large cycle 24.
See ARLP010 from 2006 at

Mark Bell, K3MSB from Airville, Pennsylvania writes: ''Just read Jeff
Hartley's, N8II, comments about the IARU radiosport contest in
ARLP030.  For me, the biggest surprise was working 5B4AII (1530Z)
and TA3D (1635Z) on 10 CW from PA !!  They were not strong, and didn't
last too long, but I got 'em.  As Jeff said,  the HQ stations were
beacons on 10M!!''

Regarding six meters on June 22, Ed Oswald, W3DUB of Sinking Spring,
Pennsylvania wrote: ''Probably not the first mail you got about six
meters today but what a morning/afternoon here in FN10.  6 was open
today here from the time I first got on the radio around 1600z to
right around 2000z, first opening north/south with lots of stations
heard here and worked from Alabama, Georgia, North Carolina, and
Tennessee (W3GQ, K4LF, KM4QQ, K4AAK).  Stations were booming in S9+
and the band seemed pretty packed.  Around 1830z or so the band
started going east/west with Minnesota, Illinois, Iowa, and
Wisconsin coming in, with K9ZVZ, N2BJ, N0VZJ, and N0JJQ worked''.

''Have to say the highlight of my day was the contact with KP4A
around 2000z on 50.110.  That was my first ''DX'' on 6m. Altogether a
dozen contacts over four hours and 11 grids.  Being new here, those
11 were all new so I'm pretty happy!''

''Not too shabby for 100 watts using an 80-10 vertical tuned for 6
(if I say so myself)!''

Several readers sent stories from Science Magazine
( and the Baltimore Sun
( that have nothing to do with
propagation, but are interesting pieces on solar physics.

For the next week, there are no predictions indicating more
sunspots.  Predicted planetary A index for the near future is 5,
with a slight increase to 8 on August 1, and a large increase to 20
on August 8.

Geophysical Institute Prague predicts quiet geomagnetic conditions
through the end of the month, except July 27, which is quiet to

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 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 July 17 through 23 were 0, 11, 12, 11, 0, 0, and
0 with a mean of 4.9.  10.7 cm flux was 65, 65.3, 66.4, 65.9, 66.2,
65.8, and 65.5 with a mean of 65.7.  Estimated planetary A indices
were 5, 5, 3, 3, 6, 11 and 16 with a mean of 7.  Estimated
mid-latitude A indices were 3, 5, 1, 2, 5, 9 and 12 with a mean of


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