ARRL

ARRL Propagation Bulletin ARLP032 (2011)

SB PROP @ ARL $ARLP032
ARLP032 Propagation de K7RA

ZCZC AP32
QST de W1AW  
Propagation Forecast Bulletin 32  ARLP032
From Tad Cook, K7RA
Seattle, WA  August 12, 2011
To all radio amateurs 

SB PROP ARL ARLP032
ARLP032 Propagation de K7RA

Average daily sunspot numbers declined over 24 points to 75.1 this
week, and average daily solar flux was down over 12 points to 104.3.
Big events this week were solar flares, with a substantial
geomagnetic upset on Friday and Saturday, August 5 and 6, when the
planetary A index was 49 and 31.  The largest solar flare of the
current sunspot cycle, an X7 flare, occurred at 0805z on August 9,
emerging from sunspot group 1263. This does not appear to be
earth-directed.
 
The latest forecast from NOAA has solar flux at 85 on August 12-13,
at 90 on August 14-16, 95 on August 17-18, 98 on August 19-20, 100
on August 21, then 105 on August 22-30.  Planetary A index is
expected to be 5 on August 12-14, then 15, 18, 12, 5, 8, 5, 12 and 8
on August 15-22, 5 on August 23-25, and 15, 10, 8, 5 and 5 on August
26-30.
 
Reviewing recent sunspot activity, on August 4 there were four
sunspot groups visible, 1260, 1261, 1263 and 1266.  Total area
covered by sunspots was 1380 millionths of a solar hemisphere, the
largest coverage since March 8, 2011.
 
On August 5 new sunspot group 1267 appeared, and on August 6 groups
1260 and 1266 disappeared, and new group 1268 arrived.  1268
disappeared and 1266 reappeared on August 7, and on August 8, 1261
was gone and 1268 emerged again.  1268 then vanished again on August
9.  On August 10 sunspot group 1267 was gone, and 1268 came back.
On August 11 sunspot group 1263 was gone, and new groups 1269 and
1270 appeared.
 
Kent Doucey, N0IRM of Galena, Missouri was on 20 meter SSB on August
3, and at 0239z worked Victor, E51CG on Rarotonga.  Signals were
strong, so they switched to 10 meters and connected again, this time
with weaker but quite readable signals, at a distance of about 5,900
miles.  If you look up both of these stations at QRZ.com, you'll see
some nice photos of their antennas.
 
Jeff Hartley, N8II of Shepherdstown, West Virginia wrote on August
6: "We had some nice sporadic E on Wednesday the August 3 evening
here with 6M open to W9/0.  I very briefly worked WA2BEV in Butler,
PA on 10M only about 190 miles away via Es and logged a couple of MI
stations there, possibly the result of the flares.  Conditions on
the 11th (this is confusing, as the email was sent August 6) were
decent with very good prop to VK and LP into ZS on 20M around 12Z.
I then went up to 15 to find ST0R on CW about S4 here and not
workable thru the EU/JA pile up (in 15 minutes they worked no NA
stations).  Returning after 15Z, I luckily found their QSX frequency
and was the next QSO with ST0R signal up to about S6.  I then tried
12M and worked PA1CC about S5 and CS2W on CW.  A listen on 10M
yielded hearing an I-ZERO beacon an hearing IW0 working someone not
audible, but CQs yielded no QSOs.  Signals on 15M in the 15Z hour
were good up to LY and SM, but nothing heard from Russia.
  
Regarding W7FA, Vince's comments about solar flare/storm enhancement
of signals, this is definitely true even sometimes over polar paths.
But another factor, time of day, would explain a big difference in
signal strength; his SSB QSO with ST0R in the 23Z hour was at a time
when signals would be expected to be much weaker than approaching
west coast sunset around 02Z".
 
Robert Elek, W3HKK of Johnstown, Ohio is excited about six meters.
He sent this: "HUGE 6m Es opening from central Ohio to New England
and the Maritimes this Sunday morning (August 7) around noon, with
signals the strongest I've heard them all season.  Mick, W1JJ with
his box 9 el Yagis on a cell phone tower took my S-meter to
unparalleled heights ... 40 dB over!  And VE1SKY, Roger, and I had
what seemed like a one hour arm chair rag chew on a variety of
topics, while the S meter rolled between 20 over and S7.  Lots more
folks getting into MS with the WSJT software, as a way to use 6m in
the 'off-season.'  Then worked a couple of 59+ sigs from the NYC
area which is very short Es, indicative of intense sporadic E
ionization.  I even heard stations to my west while beaming ENE.  As
I rotated the 5 el Yagi west they dropped out, so I was hearing S3-4
sigs from behind me also bouncing off the same sporadic E cloud
(backscatter) that was propagating sigs so well from New England.
Incredible!
 
Two days earlier, on Friday night between 6-7:30 pm, I made my first
AU(aurora) QSO ever on 6m, and then 23 more, into MI, ON, WI, MN,
IL, IN, IA, PA, MD, VA, KY, TN, MD and OH.  Strangest of all the
buzz-saw sounding CW notes was KA1VHF, Steve, located a mere 20 mi
west of me.  We've worked a few times but this was the first time
via AU!  Amazing to hear a local coming in via AU!
 
And two days before that, on Wed around 1430z I added G8BCG and
G4RRA plus CU2JT to the grid square collection for this season.
 
And the previous Sunday night I even checked into the LoneStar Net
in TX, with NC W5HNK and the boys all with 5-9 sigs rag chewing via
their groundwave but also picking up check ins from Ohio!
 
So what a week it was!  DX, Es the loudest of the season, and AU!
6m ain't dead yet!"
 
Thanks, Robert!
 
Earth is currently moving through debris from the comet
Swift-Tuttle, which gives us the Perseid meteor shower, which should
peak August 12-13.
 
If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.
 
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
http://arrl.org/w1aw-bulletins-archive-propagation.  Find more good
information and tutorials on propagation at
http://mysite.ncnetwork.net/k9la/index.html.
 
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 August 4 through 10 were 81, 94, 85, 89, 80, 54,
and 43, with a mean of 75.1. 10.7 cm flux was 116.3, 109.4, 110,
105.4, 101.5, 97.5, and 90.3, with a mean of 104.3.  Estimated
planetary A indices were 4, 49, 31, 7, 10, 9, and 7, with a mean of
16.7.  Estimated mid-latitude A indices were 3, 32, 14, 6, 8, 5, and
8, with a mean of 10.9.
NNNN
/EX