ARRL

ARRL Propagation Bulletin ARLP047 (2012)

SB PROP @ ARL $ARLP047
ARLP047 Propagation de K7RA

ZCZC AP48
QST de W1AW  
Propagation Forecast Bulletin 47  ARLP047
From Tad Cook, K7RA
Seattle, WA  November 26, 2012
To all radio amateurs 

SB PROP ARL ARLP047
ARLP047 Propagation de K7RA

This bulletin was delayed several days due to the Thanksgiving
holiday, but is up-to-date as of Monday morning.

In Propagation Forecast Bulletin ARLP046 on November 16, the average
daily sunspot number on November 8-14 was 104.9. In the next seven
day reporting period, November 15-21, the average was 126.9, a nice
increase. With solar flux, the average over the previous period was
129.5. In the most recent period it increased to 138.9.

In the four days (November 22-25) since the last reporting period
ended, sunspot numbers were weakening at 93, 85, 87 and 64. Solar
flux was 127,7, 126.7, 118 and 121.6.

The latest prediction from NOAA/USAF on Sunday, November 25, has
solar flux at 120 on November 26, 115 on November 27, 110 on
November 28, 105 on November 29-30, 100 on December 1-3, 120 on
December 4, 125 on December 5-6, 130 on December 7-11, 135 on
December 12-15, and peaking at 140 on December 16-17. It then drops
to a minimum of 110 on December 26-28 before rising again.

The planetary A index is predicted at 11 and 15 on November 26-27, 8
on November 28-29, 10 on November 30, 8 on December 1, 5 on December
2-4, 10 on December 5-8, 5 and 8 on December 9-10, 5 on December
11-15, 8 on December 16, and 5 on December 17-31.

OK1HH predicts quiet conditions November 26, quiet to unsettled
November 27, active to disturbed November 28, mostly quiet November
29 through December 2, quiet to unsettled December 3, quiet to
active December 4, quiet December 5-8, quiet to unsettled December
9, and quiet to active December 10-11.

On November 19, Jon Jones, N0JK of Lawrence, Kansas reported 6 and
10 meter sporadic-E propagation.  He wrote, "I heard the W4CHA/b
EL88 50.079 MHz on Es around 1740 UTC. No live ops around. About 10
minutes earlier I worked PT0S while fixed mobile on 10M SSB. I was
running 100W and a mag mount whip antenna on the car. PT0S peaked up
to 10 over S-9. I was on a high ridge with a clear shot to PT0S
across the Wakarusa river valley, which helped."

PT0S was the expedition to St. Peter and Paul Rocks, which sits in
the mid-Atlantic Ocean at 0.9169 degrees north, 29.335 degrees west.
We received another interesting report forwarded by Frank Donovan,
W3LPL of Glenwood, Maryland. The report comes from last Thursday,
November 22, and was written by George Wallner, AA7JV, who was on
the expedition.

Excerpts follow: "During the short openings to JA, the demand is
very strong and pile-ups have very high densities that make copy
difficult. Still, we are happy as we have over 2500 JA contacts in
the log.

"There was a very good opening late afternoon on 6 meters.
Interestingly, just a few minutes before the opening 20, 17 and 15
meters went almost completely dead. I was operating 20 meter CW and
had a huge pile-up. Within one minute the pile-up completely
disappeared. There was not even one weak signal to be heard. Almost
instantly, the 6 meter radio came alive and we had over 200 QSOs in
90 minutes, mostly with Southern Europe. A very nice surprise!  20,
17 and 15 meters recovered within a few minutes and we had big
pile-ups going 15 minutes after the beginning of the disturbance.

"We got on 160 just after sunset at 2000Z. We could hear EU stations
working each other, but nobody could hear us. We QSYed to 80 meters,
where conditions were worse; 80 sounded like a bad 160. We then
moved to 40 and worked both CW and SSB for a few hours, returning to
160 at 2145Z, by which time 160 was in decent shape and we were able
to work a steady stream of EU stations until about 1230Z, when
conditions deteriorated. We QSYed the main station between 40 and
160 meters a few  times, trying to make QSOs while keeping our
fingers in the 160 meter pie. We finished with 160 at sunrise but
could not hear any JAs, just the odd NA caller, with mostly weak to
very weak signals. We quickly QSYed to 40 at 0730Z where we were
able to work a steady stream of JAs until about 0830Z, when the band
suddenly closed to JA. Meanwhile, the second station was working NA,
EU and JA on 80 meters, under good conditions until 0800Z."

The disruptions George spoke of were no doubt triggered by one or
more of the several coronal mass ejections that our Sun spewed forth
last week.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at
http://arrl.org/propagation-of-rf-signals. For an explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. Find more good
information and tutorials on propagation at
http://myplace.frontier.com/~k9la/.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for November 15 through 21 were 132, 141, 163, 136,
122, 119, and 75, with a mean of 126.9. 10.7 cm flux was 141.7,
138.3, 135.5, 141, 133.9, 141.2, and 140.4, with a mean of 138.9.
Estimated planetary A indices were 3, 5, 7, 5, 4, 11, and 7, with a
mean of 6. Estimated mid-latitude A indices were 3, 5, 7, 4, 3, 10
and 7, with a mean of 5.6.
NNNN
/EX