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ARRL Propagation Bulletin ARLP027 (2010)

ARLP027 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 27  ARLP027
From Tad Cook, K7RA
Seattle, WA  July 9, 2010
To all radio amateurs 

ARLP027 Propagation de K7RA

Average daily sunspot numbers for this week rose from 11.7 to 16,
back to the level of two weeks ago.  Geomagnetic indices have
quieted down, with average mid-latitude A index dropping over five
points from the previous week.

Sunspot group 1084 has continued to dominate.  It first appeared on
June 27, and has continued for 12 days.  For June 27 through July 8
the relative size of the sunspot group (in millionths of a solar
hemisphere) was 90, 90, 100, 110, 110, 100, 150, 110, 100, 110, 100
and 50.

In addition, there was a single day appearance of sunspot group 1085
on June 29 with a relative size of 10, and group 1086 made a three
day appearance with a relative size of 10 on July 5-7.

Just as sunspot group 1084 fades it looks like old group 1082 is
making a reappearance.  It last was on this side of our Sun on June
17-25, and it is now visible over the eastern limb.

The latest NOAA/USAF forecast shows a rising solar flux for July
9-15 of 76, 78, 78, 78, 80, 80 and 78, accompanied by low planetary
A index for the same period of 6, 5, 5, 5, 8, 12 and 8.

Geophysical Institute Prague predicts quiet to unsettled conditions
July 9-10, quiet July 11-12, and unsettled July 13-15.

Jeff Hartley, N8II of Shepherdstown, West Virginia reports that on
Friday, July 2 around 2300z six meters was open to 9Y4VU (Trinidad
and Tobago), CO8LY (Cuba), FG5FR (Guadeloupe) and a TI5 (Costa Rica)

Jeff also sent an update for the weekend: "I spent a lot of time on
the radio over the holiday weekend.  Conditions were spectacular for
multi-hop sporadic E at times.  The evening of the 2nd your area in
NW WA was in the bull's eye for double hop Es on 6M.  Signals from
the Seattle area were actually over S9 from several stations, but no
VE7's heard.  Also southern CA and AZ were in for long stretches.  A
few stations were worked scattered around the Rockies in NV, UT, ID
as well as NM.  5 new grids were worked, all double hop except for
K7RE in SD.

Saturday morning July 3rd, I was awake early and found a couple of
EU on 15M, so tried a CQ on 28400 SSB and was immediately answered
by DO6AN at 1149Z.  Between then and 1254Z, I worked in order of
first QSO with country 8 - DL's, 2 LZ including LZ2JR/qrp, 9 G,
5B4AIX, 3 ON, 3 PA, 6 I, 15 F, 2 EA, 2 GW, EI.

I was tuning 6M off and on during my run on 10 to no avail and
finally found F6KHM calling CQ, then worked GJ4FDM first call for a
new country, and ON4GG.  By the time breakfast was over 20 minutes
later both 6 and 10M were closed to EU.  6M was open to W0, and W5,
and sometimes FL most of day until 21Z.

On Monday the 5th, I heard a beacon from EU as well as several from
Seattle and VE7 very loud at 6 AM PDT on 10M.  I called a couple of
CQ's towards EU with no luck, tuned and found a loud F8KHF running a
big station then CQ'ed again on 28455.  Between 1305-1404Z and again
1450-1515Z (band never closed in between), the following were worked
in order of first QSO with country: 11 F's, 17 G, 11 I, 5 DL, GM,
4O3A, OM3LZ, RA6XV at 1332Z, RZ6AW, GU4LJC, 5 PA, 2 EA, RV1AC,
The band was still open well to G when I QRT'd.

Quite a few new ops missed an opportunity to work new countries on
10M; the USA activity was surprisingly low.  Be alert for beacons
and don't be afraid to call CQ.  I also heard the EA4Q beacon Sunday
afternoon, but couldn't raise anyone on CQ's".

Rod Vorndam, K9ROD of Rye, Colorado lives at 7,000 feet elevation in
a rare grid square.  He writes, "Seems like there is a lot more 6
meter activity during the day this year.  When I worked 6 meters 3
to 4 years ago, most of the activity was in the evening hours.  I
loved working a pile up on July 1 in the evening hours (54 contacts
in 1 1/2 hours). I live in DM77 which is 40 on the rare list (Many
thanks to the people that did the Fish Memorial Study to determine
grid square rarity).  I can't image not living in a rare grid
square.  Looking forward to 6 meters getting even better."

I believe the Fish Memorial Study refers to Fred Fish, and a report
on rare grid squares is at

Peter Laws, N5UWY of Norman, Oklahoma wrote about odd, short path
propagation during Field Day on 10 and 15 meters.  "From N5UWY, I
worked K5PXP on 10 meters, 375 km (233 miles) to my east.  More
surprisingly, to me at least, I worked W5MRC on 15 meters, a mere
226 km (140 miles) to my south.  A few minutes later, a few kHz up,
I worked N3IC at 1869 km (1161 miles).  All contacts were all around
0330 UTC on June 27.  I don't think I've ever made a contact that
short (375 km) on 15, save for a few contacts in my own county".

John Tudenham, W0JRP of Joplin, Missouri mentioned more short skip
on 15 meters during Field Day.  He wrote, "You didn't mention about
the good E skip on 15 meters on field day.  I worked mostly 15 meter
CW from Joplin MO ARC field day station W0IN made over 60 contacts
on CW on 15 and about 20 on 15SSB from here in SW Missouri, E skip
was as close as IL, KY, TN and NTX.  Good signals, also worked on F2
two stations in Hawaii and one Virgin Islands, running 100 watts to
a homebrew ground mounted vertical, also a few contacts on 10 and 6
loading 15 meter antenna".

Also from Missouri, Kent Doucey, N0IRM of Galena, Missouri reports
"I wanted to drop you a line about the nice band openings here in
Southwest Missouri on July 4.  Early in the day, around 1300z to
1400z great contacts were made on 20 meters to South Korean stations
DS5FNE, HL5NLQ, and HL4CBX with solid 57 signals.  Also a nice
contact with V85RY from Brunei was made at the same time with a fair
54 signal.  Signals seemed to be solid with little fade on a very
quiet band.  It was nice to see these stations since the conditions
have been poor for the past bit.

Then on the afternoon of July 4th at around 2100z to 2200z contacts
were made with HA4FF, 4O3A, IK4GRO, CT1DVV, and F5BZB on 10 meters.
Signals ranged from 53 to 57 with QSB into Southwest Missouri, but
were all workable.  It was nice to see 10 meters open to Europe
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 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 July 1 through 7 were 11, 11, 11, 11, 23, 23,
and 22 with a mean of 16. 10.7 cm flux was 73, 73.4, 72.4, 71.6,
72.7, 72.7 and 74.1 with a mean of 72.8. Estimated planetary A
indices were 12, 9, 7, 5, 5, 3 and 3 with a mean of 6.3. Estimated
mid-latitude A indices were 8, 8, 6, 5, 2, 1 and 2 with a mean of


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