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ARRL Propagation Bulletin ARLP050 (2013)

ARLP050 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 50  ARLP050
From Tad Cook, K7RA
Seattle, WA  December 6, 2013
To all radio amateurs 

ARLP050 Propagation de K7RA

Due to the Thanksgiving holiday in the United States (Canada
celebrates the same holiday on the second Monday in October, same as
Columbus Day in the United States) we had a short bulletin on
Wednesday last week, and a catch-up bulletin on Monday morning,
December 2.

If you missed it, you can read it online at and see last
week's early bulletin at .

Solar activity bounced back this week, with average daily sunspot
numbers increasing from 63.6 to 102.9, and average daily solar flux
from 130 to 132.9. There were no periods of disruptive geomagnetic
activity, although November 30 and December 1 were slightly
unsettled. There was another uptick in activity yesterday, December
5, when the solar flux readings at Penticton were 157 at 1800 UTC,
149.6 at 2000 UTC and 156 at 2200 UTC. The daily reading at 2000 UTC
(local noon in British Columbia) is always the official solar flux
value for the day.  The sunspot number for December 5 was 103, up
from 98 the day before.

Predicted solar flux for December 6-7 is 155, on December 8-9 it is
150, then 145 on December 10-11, 135 on December 13-14, 130 on
December 15-16, 135 on December 17, 130 on December 18-19, 125 and
130 on December 20-21, 125 on December 22-23, 130 on December 24-26,
and 125 on December 27-28.

There is an odd solar flux peak at 165 predicted for January 8, but
this seems to be a remnant of a prediction from November 25 through
December 1, when there were many days in mid-December, late December
and early January with solar flux predicted at 160-165. On December
2 these predictions were radically revised downward, with the
exception of January 8. From November 25 to December 1 the solar
flux prediction was 165 for January 4-10, but starting on December 2
that prediction was revised to solar flux at 130 on January 4-7 and
135 on January 9-10 and 130 on January 11-12, with January 8
standing alone at 165.

You can see these changes at, at least for a
few weeks.

Predicted planetary A index is 8 on December 6, 12 on December 7-8,
5 on December 9-12, then 10 and 8 on December 13-14, 5 on December
15-25, then 12, 10, 8, 12 and 10 on December 26-30.

OK1HH sends his geomagnetic prediction from the Czech Republic. He
sees quiet to unsettled conditions December 6-7, mostly quiet
December 8-11, active to disturbed December 12, quiet December
13-14, mostly quiet December 15, quiet to unsettled December 16,
quiet December 17-18, quiet to unsettled December 19, quiet December
20-24, mostly quiet December 25, quiet to unsettled December 26,
quiet to active December 27, quiet December 28, mostly quiet
December 29, and quiet on December 30-31.

NASA released a new Solar Cycle Prediction, but nothing has changed
except the date:

Actually the information seems a bit dated, but of course they are
dealing with smoothed sunspot numbers, which are immune to daily
variations. The smoothed sunspot number is an average for an entire
year, so we are always six months behind in knowing the latest real
smoothed number. Go to and note the numbers
for January through April 2013 on page 18. This report is over a
month old, but at that time the April 2013 value was the latest
known smoothed number. Each month after that incorporates
progressively less real sunspot data and more predicted numbers.

But also note that in this table they show the current cycle peaking
in April and May of 2014. So we may not be at the peak for this
cycle after all.

Larry Godek, W0OGH of Gilbert, Arizona sent this: "I was listening
on Tuesday afternoon (December 3) for VU7AG, weakly on SSB and then
with a polar sound later in the PM. Had called him a couple times on
CW early on with no response but the frequency was crowded with
people all over the place hearing him apparently. Working on the
bench and listening at the same time, kinda. Well the signal seemed
to be getting stronger and after donning the headset I could not
hear as many stations calling him as before but he was working a lot
of 7-land and 0 call area stations. I tuned around up and down about
2 KHz from his frequency but couldn't hear any of the stations he
was calling.

"Then I heard a good loud 7-land station go back to him with the
exchange. I quickly zero beat him and when the VU7 stood by I gave
him a quick call. He came back to a W0, so I called him again and he
came back with my call. That was at 2151:30 on December 3 on 14.030
MHz. That was really the only time during all of his operating that
I really heard him well enough to make a contact. I had heard him on
SSB but getting into that fray with only 100 watts and a low 4
element Yagi doesn't get me many contacts against the multi-KW and
100ft plus stacked beam stations.

"Then at 2301 I worked JA3HAW and at 2304Z I worked JH0KZQ on 29.6
MHz FM. I've worked Europe and South America on 29.6 FM, but it's
been many a year since I even heard a JA on that frequency. I
thought I heard some Russian stations as well but not knowing the
language it was hard to tell where they were from.  Then today,
December 4 at almost the exact same time I worked the JA3 and JH0
stations, again on 29.6. They were calling CQ DX. I didn't hear them
go back to any other station before the path was lost.

"BTW, I have heard nothing of the VU7 again since yesterday although
I hear lots of other stations working him."

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 web page at For an explanation of the
numbers used in this bulletin, see An archive of past
propagation bulletins is at More good
information and tutorials on propagation are 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 November 28 through December 4 were 100, 95,
102, 104, 124, 97, and 98, with a mean of 102.9. 10.7 cm flux was
132.9, 128.5, 131.2, 130.5, 133.7, 135.7, and 138, with a mean of
132.9. Estimated planetary A indices were 2, 8, 9, 10, 2, 7, and 4,
with a mean of 6. Estimated mid-latitude A indices were 1, 6, 7, 7,
1, 6, and 3, with a mean of 4.4.


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