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ARRL Propagation Bulletin ARLP051 (2012)

ARLP051 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, K7RA
Seattle, WA  December 21, 2012
To all radio amateurs 

ARLP051 Propagation de K7RA

It is Friday, December 21, 2012, and the world did not end. To
herald this non-event, NASA even produced a wonderful video
explaining how the whole thing was a misconception anyway. The Mayan
calendar is like an odometer, and when it gets to 999999, it just
roles over to 0 and begins anew.

You can watch the video at and be sure to check out
the HD and full-screen options.

As expected, Phil Plait of "Bad Astronomy" also provides a
nonsense-free assessment at Check his blog at and Phil, a solid friend
of science, refers to the non-event as the "Maya Notpocalypse."

Solar activity increased this week, but only slightly. Similarly,
geomagnetic indices were up as well, but not by much.

Average daily sunspot numbers increased 24.5 points to 72.1, and
average daily solar flux was up by 14.8 points to 117.5. Expressed
as a percentage, the average daily sunspot number increase seems
large, but it is still in the area of low solar activity.

Average daily planetary A index increased 3.4 points to 5.4, and
average daily mid-latitude A index increased 2 points to 5.1. This
is still low activity, with the A index good for 160 meters, but
sunspot numbers not what 10 or 15 meter operators would like to see.

NOAA and USAF predict 10.7 cm solar flux numbers at 115 for December
21-24, 120 on December 25-27, 100 on December 28-29, 95 on December
30 through January 3, 100 on January 4, 105 on January 5-7, 110 and
115 on January 8-9, 120 on January 10-12 and peaking at 125 on
January 13-14. The prediction shows flux values dropping below 100
on January 26-30, and then rising above 100 in February.

We see planetary A index at 5 on December 21-22, 8 on December
23-24, 5 on December 25-28, 8 on December 29, then 5 on December 30
through January 12. We see a big jump to 16 and 12 on January 13-14,
then dropping back to 5 again into February.

OK1HH believes that "Present type of development in solar active
regions and its configuration reduces the reliability of
predictions."  He also says the geomagnetic field will be active to
disturbed on December 21, mostly quiet on December 22-23, quiet on
December 24, mostly quiet December 25, quiet December 26-28, quiet
to active December 29, quiet December 30-31, mostly quiet January 1,
quiet January 2-5, quiet to active January 6, quiet to unsettled
January 7, quiet January 8-9, mostly quiet January 10, quiet to
unsettled January 11-12, active to disturbed January 13.

Tom Morton, CXC7TT from Rocha, Uruguay, writes concerning the ARRL
10 Meter Contest (December 8-9, 2012): "Due to house guests, did not
participate in contest, except for roughly 30 contacts. I turned the
rig on right at 0000z on Friday night and 10m was pretty much dead
(that's 2200 local). I did hear and work XV1X (Viet Nam) at 0001
beaming LP over the SW tip of the USA so band had gone really long.
XV is about 12,000 nm from here LP. The next morning, typically good
for EU, was pretty dead. The few big guns in EU were coming thru but
not with really big signals. FH8PL at 1217z on SSB and T6LG at 1218z
on CW were pretty easy to work. The next day A45XR at 1600z on 10 CW
was another easy catch. Around 1400z on Sunday the band really
opened up to the US. My P3 had signals from 28001 that finally
tapered off around 28091 and SSB was crowded from 28300 to 28553. It
was definitely a South American day as two local multi-single
stations were running Qs big time. CW5W and CX5BW were within 200 Qs
of each other by mid afternoon Sunday. I think Jorge and his crew,
CW5W, may have the top score with over 3200 Qs.

"My rig is modest K3/100 to Acom 1000 and 3 ele SteppIR at 17 meters

"BTW, I never reported this before but last April 3 at 1545z I
worked A92IO on 6 meters for my best DX ever; a couple hours later,
worked 3 4X/4Z on 6 meter CW. Previously I had worked some
eastern/mid west USA, a few EUs and handful of Caribbean stations."

Thanks, Tom!

Peter Matsunaga, WH6EAU - who operates from Oahu's south coast with
50 watts into an end-fed wire - also had 10 meter contest comments:
"From a limited time working during the contest period, propagation
seemed better on Saturday than Sunday. On both days, I could work
only one US station, in Texas. My QTH seems to be in a dead spot for
much of continental United states due to a nearby mountain mass.
Otherwise I could work S. Brazil, Uruguay, Chile, Argentina,
Australia on Saturday, and Japan on Sunday. Signal strength to
Australia was particularly strong at times."

Kevin Seeger, NC6V of Corona, California wrote also about the 10
Meter contest: "As N9LB experienced I too noticed the band from time
to time just going dead. I checked my antenna and coax a few times
to see if they were still there. E skip openings were very, very
rare to almost nonexistent. The strangest propagation was a severe
echo on Sunday I was hearing from stations on CW located in Ohio and
Pennsylvania. At times it was so bad I couldn't copy their calls.

"I worked most states east of the Mississippi but missed the whole
W7 call area and a big part of the W0 call area. Several JAs were
worked Sunday afternoon and working into South America was a

Gerald Fasse, W8GF of Warren, Michigan wrote, "Among the toughest DX
paths from Southeast Michigan is Cambodia (regular path heading 350
degrees, and 14,000 kM). My only need was and still is 30 Meters.
Many 30 Meter spots were noted on the DX Cluster coupled with
frantic dial spinning but nil copy here. But I did manage to make a
single 20 Meter CW QSO at 1830Z on December 14. Checking W6EL's
propagation program for openings to the SE Michigan area it was
noted that possible openings occur between 1600Z and 1900Z for that
date. The point being that XU1A CQed again and again that day with
few QSOs noted probably because mid-day openings to SE Asia are not
expected. Don't always depend on the DX cluster for rare and unusual
DX info. Tune your radio!"

And finally, Jon Jones, N0JK had some 6 meter E-skip to report: "A
winter 6 meter Es opening the evening of December 16 (17th UTC) from
the Midwest across the southern states. W4IMD EM84 worked at 0112
UTC and heard WA4NJP loud. The WB5LLI/b EM40 copied at 0130 UTC."
Jon is in Lawrence, Kansas in EM17.

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 December 13 through 19 were 77, 71, 88, 74, 83,
66, and 46, with a mean of 72.1. 10.7 cm flux was 116.6, 119.2,
122.4, 119.5, 115, 116.2, and 117.5, with a mean of 102.7. Estimated
planetary A indices were 3, 3, 7, 5, 10, 6, and 4, with a mean of
5.4. Estimated mid-latitude A indices were 2, 4, 7, 5, 9, 5, and 4,
with a mean of 5.1.


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