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ARRL Propagation Bulletin ARLP010 (2015)

ARLP010 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7RA
Seattle, WA  March 6, 2015
To all radio amateurs 

ARLP010 Propagation de K7RA

Weakening sunspot activity continues. Average daily sunspot numbers
dropped from 59 in the previous seven days to 54.1 during the week
of February 26 through March 4.
Average daily solar flux actually rose a little, with values
increasing from 116.3 to 122.9 over the same two weeks. In addition,
on March 5 the noon reading for solar flux in Penticton was 140.2,
but this was an outlier, reduced by NOAA to an official value of 130
for the day.
The average daily sunspot number from December 1 through February 28
was 98.2. This value centered on January 2015 adds to our archive of
3-month moving averages. According to our moving average, the cycle
peaked in February and March 2014, with average daily sunspot
numbers of 146.4 and 148.2. The February value was calculated by
adding together all the daily sunspot numbers from January 1, 2014
through March 31, 2014, then dividing by the number of days. The
March value added all daily sunspot numbers from February 1 thought
April 30. This smoothing makes it easier to spot peaks and trends.
Since then the trend has been down in the past year.
Following February and March, the three month averages centered on
April through December 2014 were 129.6, 118.4, 112.8, 109.2, 115.6,
108.4, 107, 104.7 and 107.8. From there it dropped to 98.2 for the
recent period.
Don't forget, the vernal equinox is only two weeks away, and around
this time the Northern and Southern Hemispheres are bathed in equal
measures of solar radiation. We should enjoy enhanced HF radio
propagation. Also, this weekend is the SSB portion of the ARRL
International DX Contest. See for
details. The outlook is good for the weekend.
Predicted solar flux from NOAA and USAF is 135 on March 6 and 7, 130
on March 8 to 10, 135 on March 11 and 12, 130 on March 13 to 15, 135
on March 16 and 17, then 130 and 125 on March 18 and 19 and 120 on
March 20 and 21. Flux values then hit a minimum for the short term
on March 24 and 25 at 110, then rise to 135 on April 12 and 13,
according to the forecast.
The predicted flux values for March 6 to 12 are significantly higher
than in the March 4 forecast, used in Thursday's edition of the ARRL
Letter. Those reported values averaged to 121.4, while a day later
the average value for the same period is 132.9. This indicates a
temporary upward trend in the prediction.
Predicted planetary A index is 8 on March 6 to 8, then 12, 15, and
12 on March 9 to 11, then 8, 5, 8 and 5 on March 12 to 15, then 15
on March 16 and 17, 8 on March 18, 5 on March 19 to 21, then 15, 20
and 8 on March 22 to 24, 5 on March 25 and 26, then 15, 30, 25, 15
and 10 on March 27 to 31, and 8 on April 1 to 4. The predicted
planetary A index at 30 on March 26 is quite high, and is perhaps an
echo of March 1 and 2 when the A index was 28. Over those same two
days, the high latitude college A index at Fairbanks, Alaska was 36
and 60.
According to on March 1 and 2 a solar wind brought
aurora borealis to the Arctic Circle, and at 1530 UTC on March 2 an
M3 class solar flare erupted, but was not aimed toward earth.  A
blast of extreme ultra-violet radiation from the flare ionized the
upper layer of Earth's atmosphere, causing a radio blackout below 10
MHz.  This was most strongly evident over South America, as shown in
this blackout map at .
Petr Kolman, OK1MGW predicts mostly quiet geomagnetic conditions on
March 6 and 7, quiet to unsettled March 8 to 10, quiet March 11 to
13, mostly quiet March 14, quiet to unsettled March 15, quiet to
active March 16 to 18, mostly quiet March 19 and 20, quiet to
unsettled March 21, quiet to active March 22, active to disturbed
March 23, quiet to unsettled March 24, mostly quiet March 25 and 26,
quiet to unsettled March 27, active to disturbed March 28 and 29,
and quiet to unsettled again on March 30 and 31.
Robert Elek, W3HKK of Johnstown, Ohio wrote:
"Had fun chasing 3G0ZC around the bands with my KW to assorted wire
antennas from here in central Ohio. 10, 12, 15, 17, 80, 40, 30 and
20 meter contacts were put in the log (5 bands on one afternoon
alone!) but 160 eluded me.
Heard them twice (both nights of the 160M SSB contest) but QRM was
brutal at my end from the SSB boys. I slept through the next night's
160 meter window (I heard they peaked nicely between 5:45-6 am EST
then disappeared) but stood guard the final two nights between
5:30-6 am but heard nothing from them, or anyone else calling them,
for that matter. Read they had bad generator noise (and maybe QRN?)
that limited them to just 76 QSOs on Top Band.  Bummer.
Fast forward to 4-5 March. After working through the 3G0ZC pile ups
for Robinson Caruso Island, I was happy to just casually listen
around the bands while puttering in the (spare bedroom) shack, and
between trips to watch TV with the XYL. Bands seemed unusually quiet
- free from QRN and QRM. Frankly, not a lot coming through.
Then began an amazing sequence of QSOs. At 2357z on 4 March I worked
JY4NE on 20 CW with his nice signal. Then a few minutes later added
JT1CO on 17 meter CW at 0010z on 5 March, and E51UFF at 0020z on 10
CW.  Then JW9JKA on 20 CW at 0032z. Wow. The Middle East, Mongolia,
the S. Cook Islands in the South Pacific, and Arctic Europe all in a
span of 35 minutes - without the benefit of a beam antenna!
I took a couple hour break watching TV, happy with a very nice
world-wide string of FB DX.
Then from 0500-0612z another string began. TR8CA on 40 CW at 0500z;
then I dropped down to 160 and heard very little. But all of a
sudden TI5/KL9A went into the log at a very solid 579 at 0513z; then
as I poked around the quiet band there was KH6AT also 579 (at his
sunset, no less!) calling CQ at 0539z; and at 0550Z I heard DK2CF at
569 calling CQ.
I decided it was time to move back to 40 meters and see what was
happening there. At 0610z V73NS in the Marshall Islands was calling
CQ just above the noise. It was still daylight there, maybe 2 hours
before their sunset and he was coming through. And finally at 0612z
here comes E51UFF from the S. Cook islands again.
I had just enjoyed a feast of worldwide DX during about 90 minutes
of casual operating, covering 10, 17, 20, 40 and 160 meters. I
scanned 40 SSB and heard about a dozen EU and Russian DX stations
including a YL from Moldova who was attracting a crowd, several of
the LZ boys, etc., but nothing new DX-wise, so I pulled the switch
and went to bed.
This was one of those unexpected and very warm, fuzzy periods of
operating that you don't forget, because the propagation gods were
Excellent! Thanks for the report. In a subsequent email, W3HKK
"Tad, I've been reading up on ON4UNs Low Band DXing book and noticed
his comments about 'spotlight' propagation especially on 160 meters.
That perfectly describes several recent contacts on that band with a
KH6, a near contact with a CX6 tonight, and with a couple of
Nobody is coming through on the band. Then all of a sudden one or
two DX signals are very good copy but nobody is responding to their
CQs, so I jump in and work him. He then goes back to CQing with only
the occasional taker. Ditto with Europe. No European activity. Then
a couple of HA's are fairly strong for a while, but have few takers.
Isolated strong signals for a period of time from SA, Europe, and
the Pacific.
60 meters has been exploding with DX. With the 100 watt limit now,
and more countries getting on board, 60 meters has been a gold mine
of DX here of late. Tonight alone I worked 4Z4, GW0, ZD8, and LB6.
Imagine that! LZ, OH, K1N, HI8, CY0 and V47 were other 60 meter
contacts during February.
This new 8 direction SAL-30 receiving antenna is letting me see
where signals are coming from as well as providing a nice 20 dB or
so F/B on LF, broadcast band, and 160, 80, 60 and 40 meters. It's a
joy to have on the low bands."
You can read more about his all-wire antennas and his new receiving
antenna by logging into, then go to .
The Robinson Crusoe Island operation (which ended on March 4) has a
neat propagation tool on their web site at .
Several readers, including AB1DD have mentioned
recently, with videos by Dr. Tamitha Skov explaining solar
phenomena. Check out , and . She also
has a channel 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 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 February 26 through March 4 were 39, 58, 70, 66,
65, 38, and 43, with a mean of 54.1. 10.7 cm flux was 111.3, 118,
123.4, 127.6, 130.4, 125.1, and 124.2, with a mean of 122.9.
Estimated planetary A indices were 5, 4, 13, 28, 28, 11, and 10,
with a mean of 14.1.  Estimated mid-latitude A indices were 5, 2,
11, 23, 18, 10, and 9, with a mean of 11.1.


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