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ARRL Propagation Bulletin ARLP010 (2012)

ARLP010 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7RA
Seattle, WA  March 9, 2012
To all radio amateurs 

ARLP010 Propagation de K7RA

This has been quite a week for dramatic solar activity.  The average
daily sunspot number was up nearly 26 points to 69.4, and average
daily solar flux rose nearly 17 points to 121.9 for the period March

The latest forecast has solar flux at 140 on March 9, 135 on March
10-13, 130 on March 14, 125 on March 15-17, then 120, 115, 115, 110,
110 on March 18-22, then 105 on March 23-25.

Predicted planetary A index for March 9-13 is 27, 12, 10, 10 and 12,
then 5 on March 14-16, then 12, 15, 10, and 8 on March 17-20, and 5
on March 21-27.

A series of coronal mass ejections emerged from a very large sunspot
group (1429), and a large one produced a shockwave that hit the ACE
spacecraft at 1045 UTC Thursday. I had been out earlier looking for
aurora as well as a dark place to watch it, as the shock was
expected to hit at 0630 UTC, but that was a plus or minus seven
hours caveat on the forecast. By the time it hit, I was back at

I was using real time geomagnetic data to look for a rise in
activity, which can be accessed by hitting the "Submit Query" button
at For some
reason the shockwave was more noticeable at mid-latitude
magnetometers than those at the far north.

Early today (Friday morning) another CME hit Earth, and geomagnetic
activity is still high, with the planetary K index reaching 7.  A
good place to see changes in geomagnetic conditions recorded every
three hours is

On Thursday, NPR featured an excellent interview with Joe Kunches of
NOAA's Space Weather Prediction Center in Boulder. Listen here as he
gives a clear explanation of what a CME is, and talks about effects
to Earth and satellites above:

Note also that the Boulder facility has a Facebook presence at

Another good Facebook resource is Tomas Hood's (NW7US) Space Weather
and Radio Resources page at

More on solar activity at and

Among all of this activity, I've not heard anything from VHF
operators about auroral communications.  But we did get this
interesting note from Jim Parkinson, W9JEF of Tontitown, Arkansas:

"I operate low band (160, 80, 40) tying the feeders of my 80 meter
turnstile together as a flat top with a vertical run of 48 feet. I
run 400 to 500 watts.

"On March 7 at 0748Z, I heard K8QKY on 40 CW, with considerable
flutter on his 599 signal (some QSB), and sometimes a sort of echo,
which may have indicated simultaneous long path propagation. Gave
him a call, and Steve gave me a 5NN (from Ann Arbor, MI), and he
reported a similar sound on my sig.

"Then at 0801Z, NN6T (Kingman, AZ) gave me a call, and I observed
the same effect on Glen's signal, but he said mine sounded 'FB'
(presumably he had his 2 el beam headed in my direction, so maybe
aurora instead of long path) -- 599 in both ways, again with QSB.

"At 0837 I heard ZL1BVB, but not as strong as the two times I worked
him (days earlier)."

Note that around the time Jim worked NN6T and K8QKY, the planetary K
index was 6, and the planetary A index for that day was 44.

We also heard from Angel Santana-Diaz, WP3GW of Trujillo Alto,
Puerto Rico:

"It's 1000 UTC today March 8, and I only hear noise, a loud
'SSSHHHHHHhhhhhhh' on the lower bands. Can't hear anything on 40
meters, no CW, not even the shortwave AM stations, Nil! Now at 1015
UTC I can barely hear some local Caribbean stations on 7.188 MHz.

"About this past weekend's contest, all I can say is, WOW! 10 meters
was the band to be on, the easiest one where you could park and call
all day long. Had 400 QSOs there breaking last years record, and by
chance, just this past Friday, got my certificate for last years
contest, so what a way to start!

"Later was on 80 meters, and the best time to operate was after 0700
UTC when I did 70 contacts in an hour. In all, did 103 QSOs,
something never done in a contest. And even though I had only 27
QSOs on 20 meters during the weekend, in less than an hour, in fact
on the last one, had a chance on 14.189 and did 102 QSOs and as the
stations were coming, I never dealt with a pile-up in that way. I
felt like a pro attending everybody fast!"

Later Angel reported that conditions were improving fast.

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 March 1 through 7 were 24, 24, 52, 70, 105, 109,
and 102, with a mean of 69.4. 10.7 cm flux was 103.4, 108.2, 116.4,
120.1, 131.6, 138.1, and 135.7, with a mean of 121.9. Estimated
planetary A indices were 14, 10, 8, 12, 8, 8, and 44, with a mean of
14.9. Estimated mid-latitude A indices were 12, 10, 8, 10, 11, 10,
and 33, with a mean of 13.4.


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