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ARRL Propagation Bulletin ARLP025 (2012)

ARLP025 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 25  ARLP025
From Tad Cook, K7RA
Seattle, WA  June 22, 2012
To all radio amateurs 

ARLP025 Propagation de K7RA

Sunspot numbers seemed to be in a free-fall this week. Average daily
sunspot numbers declined over 29 points to 87. Average daily solar
flux fell 6.2 points to 126.2. (We erred in last week's bulletin
when we said the average daily solar flux for the week of June 7-13
was 115.9. It was really 132.4).

The outlook for Field Day weekend, June 22-23, is for low sunspot
numbers and quiet geomagnetic conditions. The progression of daily
sunspot numbers in the past five days (June 17-21) was 96, 66, 64,
29 and 13.

Predicted daily solar flux is just 95 for June 22-29, 125 on June 30
through July 7, then 130, 135, and 140 on July 8-10, then 145 on
July 11-12.

Predicted planetary A index is 5 on June 21-29, then 8 on June 30,
15 on July 1-3, 8 on July 4-5, 5 on July 6-7, 8 on July 8-9, and 5
on July 10-14.

The solar flux forecast improved slightly from June 20-21. On June
20, a flux value of 90 was predicted for June 21-28. Then the next
day, June 21, the predicted solar flux was changed to 95, predicted
for June 22-29.

The sunspot number at 13 on June 21 was the lowest since August 15,
2011. On the same day the solar flux dropped to 98, the lowest value
since April 13, 2012, ten weeks ago today.

OK1MGW sent a geomagnetic forecast for July 22 to July 9, 2012.
Mostly quiet, June 22-23, quiet to unsettled, June 24-29, quiet to
active June 30, active on July 1-3, quiet to unsettled July 4-7, and
quiet to active on July 8-9.

Last week two more solar videos accompanied by dramatic music
appeared at

Also check

It is also interesting to see how tabloids in the UK present science

And last,

Jim Williams, K5NN of Wichita, Kansas wrote in response to last
week's bulletin: "Some of the comments on the 1950's 10 meter
propagation were interesting. I was first licensed as a teenager in
1952. My first equipment was a Command receiver/transmitter so I
could only get on 80/40 meter CW. In 1953 I built a 6L6 Heising
modulated rig that could run 6 watts on 10 meters. I was using a
borrowed Hallicrafters S20R receiver with a pre-amp. The antenna was
a ground plane made out of military surplus steel rod.

"I worked the world! I forget my country total but it was well over
100 by the time I graduated from high school and joined the Air
Force. I was not able to return to ham radio till the mid 60s and 10
meters was still very good then. At that time I was able to run many
scheduled phone patches from Antarctica and the Military
installations in the Pacific on 10 meters into West Texas and New

The Command set that K5NN mentioned refers to a huge number of
radios available on the surplus market for next to nothing after
World War II. With a little modification these could be put on the
air, and if you look in old copies of QST and especially (if I
recall correctly) CQ magazine in the 40s and 50s, there were many
conversion articles based around these radios. I even recall seeing
one which converted a command set transmitter to SSB, which involved
gutting the unit and using a few key components.

An article on these radios, with nice photos at the bottom is at A unique image is at and another is at

Also check this photo at which I
think might be of surplus radios ready to be dumped in the ocean
after WWII. There were just too many to haul back to the United
States. At this same site, check for
many more photos of military radios from that era.

Rob Gregory, KD7H wrote about Fidalgo Island, mentioned in last
week's bulletin. Actually I noticed that W7LTQ is in Anacortes,
Washington, which is separated from the mainland by a very narrow
channel. When you drive there, it is not obvious that you are on an

KD7H wrote: "I am a big IOTA fan and I wanted to give you a
correction, regarding W7LTQ's QTH. Fidalgo hasn't qualified as being
part of IOTA NA-065 for quite some time because it doesn't meet the
'distance from shore' requirement (it's too close to the mainland,
of course). The same holds true for Anderson, Camano, Fox, and
McNeil islands.

"Regarding propagation, this past week I couldn't get to sleep so I
was on HF between 1 and 2am, and was very surprised to be able to
work into Europe, including the UK, on 20 and 17 meters (both CW and
SSB) and the ZL/VK/JA areas were coming through at the same time. I
was running about 400 watts, but only using a G5RV up about 30 feet
in fir trees alongside the house. Oddly, during the daylight hours
the bands seemed pretty dead in my neighborhood. However, yesterday,
Friday, June 15, OD5NJ had quite an amazing signal on 17 meter CW in
the late afternoon and it was well past dark at his house. If I can
hear good DX on my wire then I can determine that the bands are open
- HI! At our latitude, that hasn't happened much since last October.
Thankfully, the DX gods smiled when I worked 3C0E, 7O6T, 9N7MD, and
A5A (being retired with tons of time helps, too)."

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 Find more good
information and tutorials on propagation 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 June 14 through 20 were 114, 113, 110, 96, 66,
64, and 46, with a mean of 87. 10.7 cm flux was 148.6, 144.9, 134.5,
124, 118, 109.9 and 103.7, with a mean of 126.2. Estimated planetary
A indices were 4, 4, 19, 39, 15, 3, and 4, with a mean of 12.6.
Estimated mid-latitude A indices were 4, 4, 19, 36, 13, 5, and 4,
with a mean of 12.1.


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