ARRL

ARRL Propagation Bulletin ARLP048 (2012)

SB PROP @ ARL $ARLP048
ARLP048 Propagation de K7RA

ZCZC AP49
QST de W1AW  
Propagation Forecast Bulletin 48  ARLP048
From Tad Cook, K7RA
Seattle, WA  November 30, 2012
To all radio amateurs 

SB PROP ARL ARLP048
ARLP048 Propagation de K7RA

The average daily sunspot number for the week was down nearly 38% to
78.9, when compared to last week's average, which was 126.9. The
average daily solar flux dropped nearly 13% to 121 from 138.9. The
seven day reporting period for these data ran from November 22-28.

Predicted solar flux for the near term is 110 on November 30, 105 on
December 1, 100 on December 2-4, 105 and 115 on December 5-6, 120 on
December 7, 130 on December 8-11, 135 on December 12-15, 140 on
December 16-17, 135 on December 18-19, 130 on December 20-22, 120 on
December 23-24, 115 on December 25, 110 on December 26-28, 15 on
December 29-30, 120 on December 31, 125 on January 1-2 and 130 on
January 3-7.

The current activity and forecast for the next few days is better
than predictions we saw earlier in November.  From November 5-18 we
presented predictions showing the solar flux going below 100 on
November 27 through December 2.

Predicted planetary A index is 15 and 8 on November 30 through
December 1, 5 on December 2-6, 10 on December 7-8, then 5 and 8 on
December 9-10, 5 on December 11-15, 8 on December 16, 5 on December
17-31.  The New Year is expected to begin slightly unsettled with
predicted planetary A index at 10 on January 1-4. The following days
through January 13 have a predicted A index of 5, except for January
6 and 12, with a predicted planetary A index of 8.

OK1HH, F.K. Janda of the Czech Propagation Interest Group says the
geomagnetic field should be quiet to unsettled November 30, mostly
quiet December 1, quiet to unsettled December 2-3, quiet to active
December 4, mostly quiet December 5-7, quiet December 8, quiet to
active December 9-11, quiet December 12, quiet to unsettled December
13-14, mostly quiet December 15, quiet to unsettled December 16,
quiet to active December 17, mostly quiet December 18, quiet
December 19, quiet to active December 20-21, and quiet on December
22.

Dick Grubb, W0QM of Boulder, Colorado sent some information
forwarded some information on D-region absorption, which is
interesting to look at when there is a Sudden Ionospheric
Disturbance (SID) event.

He sent this plot showing HF attenuation during the disturbance
described by the PT0S operator in last week's Propagation Forecast
Bulletin ARLP047:
http://www.ngdc.noaa.gov/stp/drap/data/2012/11/21/SWX_DRAP20_C_SWPC_20121121153300_GLOBAL.png.

Backing up the URL hierarchy, we come to this directory:

http://www.ngdc.noaa.gov/stp/drap/data/

From there we select 2012, then November, which brings us here:

http://www.ngdc.noaa.gov/stp/drap/data/2012/11/

Select November 21, and it takes us here:

http://www.ngdc.noaa.gov/stp/drap/data/2012/11/21/

We can select data from any hour of the day, in this case he used
the 1500 UTC hour:

http://www.ngdc.noaa.gov/stp/drap/data/2012/11/21/15.html

Here we see a mind-boggling trove of data.  The particular one he
sent was the Global Plot from 1533 UTC. There are also north and
south pole plots. You can see these minute-by-minute if you want,
stepping forward and back in time.

Here is a list of A and K index readings for the third quarter of
2012:

http://www.swpc.noaa.gov/ftpdir/indices/old_indices/2012Q3_DGD.txt

Note the high numbers on July 15, 2012. It looks like the highest K
index values were at the 0600 and 0900 UTC readings.

At 0639 UTC, you can see a big effect:

http://www.ngdc.noaa.gov/stp/drap/data/2012/07/15/SWX_DRAP20_C_SWPC_20120715063900_GLOBAL.png.

This looks like an interesting tool for examining some of the
effects of solar flares.

John Dyckman, WA3KFT of Aston, Pennsylvania is on a local 10 meter
SSB net which meets daily at 1800-1900 UTC (actually 1-2:00 PM local
time) on 28.435 MHz. On November 26 he and other stations on the net
worked WA7DUH in Washington, KD0TBB, WB0Y and KD0QCF in Colorado,
N3AAW in Montana and ZS6JPY in South Africa. 10 meters seemed open
to the world, and signals were from S7 to 10 dB over S9 for the
whole hour. So even with the somewhat depressed solar activity, 10
meters is still alive.

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 22 through 28 were 93, 85, 87, 64, 81,
76, and 66, with a mean of 78.9. 10.7 cm flux was 127.7, 126.7, 118,
121.6, 121.8, 117.1, and 114.3, with a mean of 121. Estimated
planetary A indices were 2, 7, 13, 4, 5, 4, and 2, with a mean of
5.3. Estimated mid-latitude A indices were 1, 6, 11, 4, 6, 3 and 2,
with a mean of 4.7.
NNNN
/EX