SB PROP ARL ARLP027
ARLP027 Propagation de K7RA
This bulletin is a day early, as Friday is the day the United States
celebrates its independence from the British Empire. Next week we
will be back on the regular schedule.
The earth-facing side of our sun is suddenly crowded with clusters
of sunspots, so this cycle definitely is not over. Over the past
week average daily sunspot numbers rose 43.3 points to 115.6, while
average daily solar flux was up 30.7 points to 129.5. The 45 day
outlook has also improved markedly. Back in mid-June the predicted
average solar flux for the next reporting period (July 3 to 9) was
only 137.9. By June 26 the increasingly pessimistic forecast had
dropped to only 128.6 for those same dates. But yesterday, July 2,
the predicted average daily solar flux for July 3 to 9 rose to
June has ended, so now is the time to look at our 3-month moving
average of sunspot numbers. A month ago we looked at an average of
daily sunspot numbers running from March 1 to May 31, and now this
time we calculate the average from April 1 to June 30. Starting a
year ago, with the trailing 3-month average ending in June 2013, the
average daily sunspot numbers were 106.4, 97.5, 85.6, 77.4, 91.2,
102.9, 123.7, 123.3, 138.5, 146.4, 148.2 129.6 and 118.4. So using
this method, the recent peak was centered on February and March of
this year at 146.4 and 148.2. An earlier peak centered on April and
May 2013 was 106.4 during both periods, and the earlier peak was
118.8 and 118.6 centered on October and November 2011. I really
think this cycle has three peaks, but perhaps the official 12 month
moving average will show something else and smooth out that 2013
The latest short term prediction shows solar flux at 175 on July 3,
180 on July 4 to 7, 175 on July 8 and 9, 170, 165 and 150 on July 10
to 12, 130 on July 13 to 15, 110 on July 16 and 17, 115 on July 18,
then solar flux declines to 90 on July 23 and 24, rises to 165 on
August 7 and declines to 100 on August 15 and 16, but that is more
than six weeks from now.
Predicted planetary A index is 5 on July 3 to 5, 8 on July 6 and 7,
5 on July 8 to 10, 8 on July 11, 5 on July 12 and 13, then 8, 12, 8,
and 8, on July 14 to 17, and 5 on July 18 to 28, before rising to 8
You can get a daily update of the 45 day outlook for solar flux and
planetary A index at
usually updated between 2100-2130 UTC, but on July 1 the forecast
was not released until 0409 UTC the following day, or the evening of
July 1 in most of North America.
Scientific American is running another article on that citizen
science project in which volunteers are asked to look at a series of
pairs of sunspot images, and decide which of each two are more
complex. Read about it at
Jon Jones, N0JK (EM28) reported on June 28 "From 0030-0145z June 21
(Sunday evening) 2 meters opened for sporadic E from KS, NE, IA to
VA, NY, PA, NC, SC, etc.
I heard but did not work K1HTV FM18 on 2 meters with an indoor loop
antenna. A severe thunderstorm was occurring here during the
opening. N0IRS EM29 worked KN4SM FM16 who was using an indoor whip
and 10 watts on 144.200 MHz.
This is the same time frame as N8II's 6 meter report in last week's
propagation bulletin. The short skip on 6 meters he worked is
consistent with a high MUF that supported 2 meter Es."
David Moore sent a link to an article concerning phenomena called
The New York Times ran an article which mentions Dikpati's
prediction that we were all excited about some years back,
predicting a huge cycle 24. Turns out part of her prediction was
correct, just not the magnitude part. Read it here:
Pete Corp, K2ARM of Fort Edward, New York on July 1 wrote: "The last
time I wrote on May 22nd we were having a couple of nice openings,
but for me, 200 miles north of NYC, propagation went down hill
especially for 6 meters. One evening on 15M I only found one JA
station and worked him for around 20 minutes and after looking
around I found that we were the only 2 stations on. Conditions were
not good even on 15M.
There have been openings on 6 meters almost every day since May 24th
but almost all the openings have been for the stations running high
power with good antennas. The rest of North America especially the
South and West have been working Europe, Japan and South America. I
worked a few stations in North America on 5/31, 6/9, 6/18, and 6/30
and since 6/30 the 6 meter band has been open here most of the day,
from 1000Z to 2200Z.
I have worked a few more countries and Grids but it is rough with
just a dipole and only using CW. I hear Europe and SA now so
conditions are better and 15M is back to normal for awhile."
No reports came in regarding conditions over Field Day, but there
were no big geomagnetic disruptions and solar flux was a bit better
than expected. On Saturday afternoon I set up in a parking lot at
the University of Washington for some casual operation on 20 meter
CW. Like last year, I used a screwdriver antenna, but did not
attempt mobile operation this time. Instead I ran two quarter wave
radials, one each for 20 meters and 40 meters. Also made some 75
meter SSB contacts after the contest.
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 of past
propagation bulletins is at
information and tutorials on propagation are at http://k9la.us/.
Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.
Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.
Sunspot numbers for June 26 through July 2 were 72, 78, 89, 112,
124, 154, and 180, with a mean of 115.6. 10.7 cm flux was 100,
104.2, 114.6, 125.7, 140.5, 151.8, and 169.4, with a mean of 129.5.
Estimated planetary A indices were 5, 4, 6, 8, 6, 4, and 5, with a
mean of 5.4. Estimated mid-latitude A indices were 7, 4, 6, 7, 7,
6, and 5, with a mean of 6.