ARRL

ARRL Propagation Bulletin ARLP051 (2009)

SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW  
Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, K7RA
Seattle, WA  December 11, 2009
To all radio amateurs 

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

Finally! A sunspot appeared on Wednesday, December 9, giving us a
daily sunspot number of 13.  This followed 16 days of no sunspots,
and again on December 10 the sunspot number was 13.  The new group
is number 1034, and it is a solar Cycle 24 spot, as all sunspots
have been since number 1016 on April 29-30, 2009.

This weekend is the annual ARRL 10-Meter Contest.  Will there be
enough sunspot activity to enhance 10-meter propagation?  The latest
prediction for solar flux shows it rising 75-77 on December 11-12,
and staying at 77 through December 17, which probably correlates
with the new sunspot moving toward the center of the solar disk.

To significantly raise the MUF to enhance 10 meter signals over most
paths takes more sunspot activity than we are seeing this week,
although every bit helps.  But this contest often depends on
sporadic-E skip and the effect of ionized meteor trails during the
Geminids meteor shower, which should reach a peak just a few hours
after the contest ends on Sunday.  Geminids meteor showers have
intensified with each passing year as Earth moves deeper into the
debris stream from extinct comet 3200 Phaethon.

Back in Propagation Forecast Bulletin ARLP005 earlier this year (see
http://www.arrl.org/w1aw/prop/2009-arlp005.html) we reproduced a
letter written 34 years ago by Ed Tilton, W1HDQ, the originator of
this bulletin.  Ed talked about meteor enhanced 10 meter propagation
during this contest.

We were watching the current sunspot move toward the horizon a few
days ago, via the STEREO spacecraft (http://stereo.gsfc.nasa.gov/)
and wished the whole Sun were visible, which should happen in 2010.
Currently STEREO sees about 86% of the Sun.  It should reach 90% on
June 29, 2010 between 0027-0040 UTC, and 95% coverage on October 12,
2010 between 1252-1259 UTC.

A view of real time MUF maps at
http://www.spacew.com/www/realtime.php shows that during daylight
over low latitudes the MUF is going above 10 meters over the past
couple of days.

A couple of 160 meter notes since the recent contest:

Randy Whiting, KC9KHG of Woodstock, Illinois says he upgraded to
General class in March 2007, and at the time told locals he was
putting up a 160 meter inverted V with a 60 foot apex.  They told
him he would work only two or three hundred miles.

The week before last he worked KC7YM in Wyoming, a distance of 1,079
miles between their stations.  Then December 3 he worked G3JMJ, a
distance of 3,971 miles.  Both were on CW.

Markus Hansen, VE7CA of North Vancouver, British Columbia writes,
"Wow, conditions were amazing during the recent ARRL 160 meter
Contest.  I was amazed how easy it was to work NH, RI, DE, MD VA, NC
and GA from my QTH here on the west coast.  I am only running 100
watts and a very weird shaped 160 meters loop strung around my city-
sized lot.  The KH6s were bending my S meter in the mornings at
sunrise and JA3YBK was pounding in at well over S9 at 1434Z Sunday
AM. Good fun!"

Hans Goldschmidt, SM5KI says he is 82 years old and has been a ham
over six decades.  He is in the center of Stockholm, and "really was
shocked when I put up in a nearby low tree an end fed half-wave
wire, the feedpoint only 1.5 meters above the ground. Right away I
was in a 50 minute long QSO with a station in North Carolina. My
signals S7-9!  There seems to be a daily window around 1300Z to the
Eastern US States on 14 MHz and I can work K8SL and others daily
with S7-9."

"In the morning on 14 MHz we have the usual winter conditions and
the band is completely dead right now until about 0700Z. Still the
same, last week I worked daily SU9HP, a Swede on holidays down
there, on 14 at 0730Z with Q5 signals every morning, when there was
almost no other signal to be heard on the band."

"I say this because despite black-outs and the present sunspot
minimum conditions, you may still find a useful path to some DX spot
on the globe.  Sometimes it is easier to find a rare DX on a dead
band. There is also less QRM as the competing stations have given up
even to try."

"Years ago I was shocked to hear on 14 MHz two stations, not too
strong, on a completely dead band during a blackout, talking, what
it seems to be locally. They were in YJ8 and we had an unexpected
QSO. Similar QSOs occurred in the past and many were near the
equator. Whatever THAT means?"

"Finally a suggestion: Do not give up using the DX-bands just
because they seem to be dead. There may be short selective openings
to some parts of the globe. Do not rely on those awful DX clusters
but LISTEN, LISTEN!"

Thanks, Hans! Good advice.

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://www.arrl.org/tis/info/propagation.html. For a detailed
explanation of the numbers used in this bulletin see,
http://www.arrl.org/tis/info/k9la-prop.html. An archive of past
propagation bulletins is at http://www.arrl.org/w1aw/prop/.

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

Instructions for starting or ending email distribution of this
bulletin are at http://www.arrl.org/w1aw.html#email.

Sunspot numbers for December 3 through 9 were 0, 0, 0, 0, 0, 0, and
13 with a mean of 1.9. 10.7 cm flux was 71.6, 71.5, 71.7, 71.9,
71.1, 72.2, and 73 with a mean of 71.9. Estimated planetary A
indices were 0, 0, 3, 2, 2, 1 and 0 with a mean of 1.1. Estimated
mid-latitude A indices were 0, 0, 3, 1, 2, 0 and 0 with a mean of
0.86.
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/EX