9 March, 2013 ARLP010
The averages of daily sunspot numbers and solar flux
over the reporting week (February 28 through March 6) both rose, with
sunspot numbers up nearly 36 points to 93.3 and solar flux up nearly 12
points to 112.6, in comparison to the previous seven days. The most
active geomagnetic day was Friday, March 1, when the planetary A index
was 27 and the mid-latitude A index was 23. Alaska's high latitude
college A index was a whopping 64. The upset was sparked by a stream of
high speed solar wind.
The latest forecast from NOAA/USAF puts average solar
flux for the next five days (March 9-13) at 118.2, higher than average
solar flux for the reporting week, which was 112.6.
Predicted solar flux is 112 and 118 on March 8-9, 120 on
March 10-11, 118 on March 12, 115 on March 13-14, 105 on March 15, 95 on
March 16-17, 100 on March 18-20, 105 on March 21-24, 110 on March 25
through April 1, and 105 on April 2-5.
The predicted planetary A index is 8 on March 8, 5 on
March 9, 8 on March 10-12, 5 on March 13-20, 8 on March 21, 5 on March
22-27, then 18, 10, 5 and 10 on March 28-31 and 8 on April 1-4.
F.K. Janda, OK1HH predicts quiet geomagnetic conditions
on March 8-9, mostly quiet March 10-11, quiet to unsettled March 12,
quiet to active March 13, quiet on March 14, quiet to unsettled March
15-17, quiet on March 18, mostly quiet March 19-20, active to disturbed
March 21-22, quiet March 23-24, mostly quiet March 25, quiet March
26-27, quiet to active March 28-30, and quiet to unsettled March 31.
Have we mentioned recently that for HF propagation, we
generally want higher sunspot numbers but low geomagnetic indices at the
same time? At http://solarscience.msfc.nasa.gov/predict.shtml
you can see the latest NASA solar cycle prediction. They revised the
forecast downward again. Last month they said that the cycle should peak
this Fall with a smoothed sunspot number of 69. That was revised down
by three points, and now they say it will peak at 66. These are
International Sunspot Numbers, which have a lower scale than the Boulder
numbers we use in this bulletin, which run about 35% higher.
Many readers wrote in concerning the news about a
possible double-peak for the current solar cycle. There seemed to be a
peak in activity around the end of 2011, then activity fell off last
year. If true that the cycle peaks this Spring or Fall, we don't seem to
be trending toward that activity yet.
Check http://www.youtube.com/watch?v=6j4bl57D_1U for a video from NASA explaining this. Note you can watch the video in HD and full screen by selecting options at the bottom.
Thanks to John Campbell, K4NFE, Elwood Downey, WB0OEW, Gary Johnson, K5SWW, and David Dary, W5ZAX, for the tips on the story.
If you go to http://www.swpc.noaa.gov/weekly/pdf/prf1957.pdf
for the latest Preliminary Report and Forecast and turn to page 15, you
can check the numbers for the latest prediction from Boulder. It shows a
peak in September and October 2013, with levels about 27% higher than
solar activity last month, February 2013.
See also that the peak in activity at the end of 2011 is
represented by the higher numbers (smoothed, so the peak is not
pronounced), then gradually declining. The averaging function seems to
have moved that peak out to February and March of 2012. But the
predicted peak this year is quite a bit higher than the previous peak.
Let's hope that the second peak is indeed much more robust, as
the forecast from last month shows higher values for the end of 2012
and the first few months of 2013. These reflect estimated future sunspot
numbers, which would drag the average down. The numbers for each month
are an average for a year's worth of data, six months forward, and six
months back. The estimate for March 2013 went from 77 last month to 73
this month. The latest figure represents one more month of real recorded
data than last month's prediction.
Note also on the next page that the solar flux prediction shows the peak for that parameter in August 2013.
Julio Medina, NP3CW of San Juan, Puerto Rico wrote, "Just
to let you know that today 01 March 2013 from 1826-1837z I worked
VU3WIJ and VU3WII on 20 meter SSB with 5x9 reports both way. I was using
a vertical antenna at ten feet above the ground and 100 watts. Both
stations had pile ups and they copied my signal very easily."
I replied, "On that day I would expect the band to just
begin to open at that time, but signals should reach a peak from
Steve Hawkins, NG0G wrote: "On March 5 at 2213Z I had
just worked TX5K (Clipperton Island) on 24 MHz CW. I live in Boone Iowa
and it was getting on toward late afternoon." (See http://www.tx5k.org/ for the Clipperton DXpedition.)
"After working TX5K I stumbled across XT2TT (Burkina
Faso) on the same band. Since by then it had been dark in Africa for
hours I was very skeptical and thinking pirate. But I adopted the
standard 'Work now, worry later' mode.
"I'll admit it took tweaking everything built into my
FT-1000 MKV Field, and listening so hard there may have been arcing
inside my skull, but I could hear them. I called and worked them about
the 3rd call. At first I thought 'nooooooo, this must be a pirate,' as
with my wimpy vertical, and the solar flux as low as it is, 24 MHz
should not be open to Africa from Iowa at 2213Z. I was astounded when
not only did they answer me, but I quickly showed up in their online
"I could almost hear http://www.youtube.com/watch?v=NzlG28B-R8Y (cue the Twilight Zone theme music.)
"Despite feeling like the guest on a certain late night
talk show, I quickly launched into my best post-back surgery version of
the 'Happy Dance.'
Talking later with a friend, K0KT, he reminded me that near to the equator, the MUF can be surprisingly high up to midnight."
Actually when running the numbers on W6ELprop,
propagation over that path at that time on that band is not unusual. I
entered 42.07 degrees North, 93.88 degrees West for Steve's location,
and found the XT2TT DXpedition QTH at, http://www.i2ysb.com/idt/index.php?option=com_
That page shows a grid square location of IK92fi, so I entered this into the AMSAT grid square conversion tool at http://www.amsat.org/cgi-bin/gridconv.
This yielded 12.3542 degrees North, 1.54167 degrees West
for XT2TT. This turns out to be only 25 miles north of the default
Burkina Faso coordinates in W6ELprop.
Based on these coordinates, the station is in the
southwest portion of Ouagadougou, Burkina Faso's capitol city. I checked
this at 4:17 AM Seattle time today, which is 12:17 PM in Burkina Faso
and also 1217z. The temperature was 102 degrees F with humidity of only
11% in Ouagadougou. The annual rainfall there is only 35 inches, and the
high temperatures between March and May reach 113 degrees F.
The path length is 5,767 miles (9,281 km), and on March 5
W6ELprop shows an opening beginning with a B rating (available 50-75%
of the time) and signal-to-noise ratio of 40 dB at 1330z, changing to an
A rating (opening 75-100% of the time) by 1430z. By 1830z the s/n ratio
is 43 dB and it gradually increases to a peak of 48 dB at 2300z.
Signals stay at that level, but availability degrades to a B rating at
2330-0000z, C rating (25-50% availability) at 0030z and D rating (1-25%)
Sunset at XT2TT was 1812z on March 5, and at NG0G it was
0006z. So that path opens about 45 minutes after sunrise at NG0G
(1248z), gets better after sunset at XT2TT, and finally begins fading
around sunset at NG0G. A half hour after sunset in Iowa, that path is
done. For more info on using W6ELprop, see references at the bottom of
this page, or check http://www.arrl.org/files/file/Technology/propagation/W6elprop.pdf.
You can download W6ELprop at http://www.qsl.net/w6elprop/.
Ken Miller, K6CTW of Rancho Cucamonga, California wrote,
"I was up late last night working on the computer and saw that the
Clipperton DXpedition was operating on 80 meter CW near the bottom end
of the band. Just to satisfy my curiosity I turned on the 1960s station
I've restored (Heathkit DX-60 with homebrew DDS-VFO and Drake 2-B
receiver with 2-BQ Q-Multiplier feeding an inverted-vee dipole antenna)
to see what I could hear. (Ken runs the old Novice power limit on this
rig, just as he did on the same setup in 1967, 75 watts, or about 40-45
watts out.) Their signal here in Southern California was 20 over S-9 or
better so I loaded up the DX-60 and gave a call after figuring out where
the operator was listening (he was running JAs). Imagine my amazement
when he came back to my call! I am always impressed that the operators
at these DXpeditions can sort out a weak signal like mine out of the
Thanks to them and also, what a surprise to see how good communications can be on the low bands late at night."
Ken wrote in a subsequent email: "I've restored this
first DX-60 (and a Drake 2-B and 2-BQ Q-Multiplier) to get my feet wet. I
am now in the process of rebuilding another DX-60 kit with all new
parts. I re-plated the chassis and all the metal, and I've added an OA2
voltage regulator tube to the power segment of the 6CL6
oscillatorsection. That will prevent chirp on 10 meters.
"The VFO is a home brew DDS unit using the now 'retired'
FCC-1 and FCC-2 from The NorCal QRP Club. For details, check the April
or May issue of Electric Radio as Ray is publishing an article I wrote
about my experience.
"I'm also home-brewing another improved version VFO using
Jim, WA1FFL's DDS unit. This one is a significant upgrade to the unit
described in the article."
If you would like to make a comment or have a tip for our readers, mail the author at, firstname.lastname@example.org.
For more information concerning radio propagation, see the ARRL Technical Information Service 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 ofpast 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/.
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overseas locations are at http://arrl.org/propagation.
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Sunspot numbers for February 28 through March 6 were 63,
88, 90, 115, 103, 106, and 88, with a mean of 93.3. 10.7 cm flux was
105.5, 112.5, 111, 112, 114.3, 118.4, and 114.3, with a mean of 112.6.
Estimated planetary A indices were 7, 27, 12, 7, 4, 4,
and 3, with a mean of 9.1. Estimated mid-latitude A indices were 8, 23,
14, 6, 4, 3, and 4, with a mean of 8.9. Source: The American Radio Relay League • All propagation reports can be found at: http://www.southgatearc.org/propagation