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ARRL Propagation Bulletin ARLP035 (2012)

ARLP035 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 35  ARLP035
From Tad Cook, K7RA
Seattle, WA  August 31, 2012
To all radio amateurs 

ARLP035 Propagation de K7RA

Although solar activity is quite low, we did see an increase in
sunspot numbers and solar flux over the past week.  Average daily
sunspot numbers were up nearly 20 points, or about 36 percent, to
74.1.  Average daily solar flux increased nearly 13 points to 108.7.
There was also quite a remarkable increase on Thursday, August 30,
when the sunspot number jumped 23 points from Wednesday's value to
118, and solar flux was up nearly 10 points in one day to 127.8.
Both of these numbers will figure into next week's averages, as our
reporting period is Thursday through Wednesday.
One new sunspot region appeared on each of the three days, August
23-25, then three new regions appeared August 27, then one each on
August 28-29, and three more on August 30.
The latest forecast has activity over the next week a bit lower than
the forecast a few weeks ago, but somewhat higher sunspot numbers
than the prediction in the August 30 ARRL Letter.  Predicted solar
flux is 130 on August 31 through September 7, 115 on September 8,
110 on September 9-10, 105 on September 11-12, 100 on September
13-16, 95 on September 17-22, then 115 on September 23, 120 on
September 24-25 and reaching a peak of 125 on September 26-28.
Predicted planetary A index is 10 and 8 on August 31 through
September 1, 5 on September 2-7, 8 on September 8-9, 5 on September
10-14, 12 on September 15-16, 8 on September 17-18, 5 on September
19, 8 on September 20-21, 10 on September 22, and 8 on September
23-25, followed by 5 on September 26 through October 4 and 8 on
October 5-6.
OK1HH predicts quiet to unsettled geomagnetic conditions on August
31, mostly quiet September 1-2, quiet to unsettled again on
September 3-5, quiet on September 6-8, quiet to unsettled September
9, quiet to active September 10-13, quiet September 14-15, mostly
quiet September 16, quiet to active September 17-18, quiet September
19, mostly quiet September 20, quiet September 21-22, and quiet to
active September 23.
We received a note from Ray Bass, W7YKN of Sparks, Nevada about how
the HF bands don't seem as good as they were during past solar
cycles.  Ray writes, "Only find ten open a little and twenty real
good once in a while and not like years past, or is my receiver
Although cycle 24 is predicted to peak between February and July
2013, solar activity this year has been substantially below what it
was toward the end of last year.  There isn't enough sunspot
activity to sustain 10 meters, although fall should provide an
advantageous seasonal variation for most paths.
Currently sunspot activity is stronger than it was exactly a year
ago.  55 days covers two complete solar rotations, and the 55 days
from early July through August 29 had a daily sunspot number average
of 87.2.  On the same days last year the average was 20 points
lower, 67.2.
We received reports of recent sporadic-e and tropo propagation on
Jon Jones, N0JK in Kansas wrote, "A surprisingly good series of
sporadic E openings on 6 meters August 24-26.  The evening of August
24 many double hop Es contacts were made from W3, W4 to California.
Earlier Central America was in to Colorado, Michigan and the Gulf
From Kansas - worked on 6 meters August 24, WA7JTM  DM33, WB7BBI
DM93 (short Es at 825 km, high MUF), K8OY  EM88, WB3BEL  FM18 and
N4OX  EM60.  This opening was 28 days (one solar rotation) after the
big 2 meter Es opening July 24.  Perhaps a solar influence?"
Jon also wrote in a later message:  "Had a strong tropo opening
Monday morning August 27 from NE Kansas to IL, MN, NE, and WI.  I
worked W9EWZ EN52, KA0PQW EN33 and KQ0J EN11 around 1330 UTC on 144
MHz.  My station was a FT-897 50 W and a 7-element M2 Yagi
portable."  Jon sent a picture of a radio sitting on a sidewalk,
hooked to a Yagi about 5-6 feet high mounted to a post in the
K1KT, Ken Tata of Warwick, Rhode Island wrote on August 24, "Tropo
has been quite good along the East Coast the last three nights.
Last night I went portable to Narragansett, RI to operate 2 meters.
When I arrived there was an onshore breeze.  Despite that, using an
11-element Yagi and 50 watts, best DX for the evening was FM17 and
FM16.  Also heard the Cape Hatteras beacon, about 480 miles away.
Everything I heard was coastal.  Except for the beacon, most signals
were in the S5 to S7 range with about 12 dB of QSB.  Signal levels
improved up til 11PM local time when I packed up and went home."
Ken wrote later and said these three nights were followed by another
three nights of good tropo activity.
Ken continued, "Since this wasn't a contest, activity was rather
light, but even relatively 'small' stations did well and had fun!
We need more activity on VHF/UHF!  There are lots of IC-706s,
FT-100s, IC-746s, and other rigs with 6 meter and 2 meter
capability.  Relatively high gain 2 meter antennas are not all that
big.  You can build a WA5VJB 'Cheap Yagi' for literally a few bucks.
You can carry an assembled 11-element Yagi or 8-element Quagi for
432 on the back seat of your car.  Portable operation can be
considerably easier and setup faster than for HF."
Ken mentioned the WA5VJB Cheap Yagi.  For more information, see, and
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email the author at,
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the numbers used in this bulletin, see  An archive of
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bulletins are at
Sunspot numbers for August 23 through 29 were 49, 69, 70, 78, 85,
73, and 95, with a mean of 74.1.  10.7 cm flux was 96.7, 104.2,
105.9, 113.2, 111.5, 111.2, and 118.3, with a mean of 108.7.
Estimated planetary A indices were 10, 9, 10, 11, 7, 4, and 4, with
a mean of 7.9.  Estimated mid- latitude A indices were 11, 9, 10,
10, 7, 3, and 5 with a mean of 7.9.


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