[IRCA] Fw: ARLP024 Propagation de K7RA

["Art Blair" <artngwen@xxxxxxxxxx>]

----- Original Message ----- 
From: "W1AW Mailing List" <w1aw-list-request@xxxxxxxxxxxxxxxxx>
To: <artngwen@xxxxxxxxxx>
Cc: <W1AW List:>
Sent: Friday, June 08, 2007 6:26 AM
Subject: ARLP024 Propagation de K7RA


> SB PROP @ ARL $ARLP024
> ARLP024 Propagation de K7RA
> 
> ZCZC AP24
> QST de W1AW  
> Propagation Forecast Bulletin 24  ARLP024
>>From Tad Cook, K7RA
> Seattle, WA  June 8, 2007
> To all radio amateurs 
> 
> SB PROP ARL ARLP024
> ARLP024 Propagation de K7RA
> 
> After five days of no sunspots from May 24-28, spots returned on May
> 29, and have increased since in number and size.  There are
> currently several sunspots visible, and the sunspot number for the
> past five days (Sunday through Thursday) was 58, 58, 63, 47 and 59.
> Coupled with quiet and stable geomagnetic indicators, this is good
> for HF propagation.  Our reporting week for this bulletin (the
> numbers reported at the end) runs from Thursday through Wednesday,
> and the average daily sunspot number for May 31 to June 6 rose
> nearly 43 points to 46.1 when compared to the prior seven days.
> Average daily solar flux rose nearly 15 points to 83.7.
> 
> Last week's Propagation Forecast Bulletin ARLP023 mentioned ARRL
> Field Day, now just two weeks away.  The bulletin reported (in some
> uncorrected versions) that the event is always held on the last full
> weekend in June, but Don Jackson, AE5K of Marion County, Arkansas
> pointed out that the rules specify the fourth full weekend.  Both
> fourth and last are on the same weekend this year (June 23-24),
> which is usually the case, but not always.  In 2002, the fourth full
> weekend was June 22-23, but the last full weekend was June 29-30.
> This occurs whenever June 1 is a Saturday, as it will be again in
> 2013 and 2024.
> 
> Last week the latest projection looked like no sunspots around Field
> Day with a declining geomagnetic disturbance, but this week the
> forecast looks a little better.  Including the Friday before (the
> event doesn't begin until Saturday) the projected solar flux last
> week for June 22-24 was 65 for all three days, with a planetary A
> index of 20, 12 and 5.  This week's prediction for those dates shows
> the same A index, but a solar flux 10 points higher, at 75 for all
> three days.
> 
> A check of recent sunspot numbers alongside solar flux values on the
> same dates at, http://www.sec.noaa.gov/ftpdir/indices/DSD.txt, shows
> no sunspots when the solar flux was down around 65, but at 75 the
> sunspot number can be in the 40s.
> 
> For the next few days expect continued quiet geomagnetic activity,
> with the same moderate (for the low point of the sunspot cycle)
> sunspot count.
> 
> Alex Mendelsohn, AI2Q in Kennebunk, Maine sent a link to an article
> about a solar burst last December 6, which caused problems for GPS
> receivers.  You can read it at, http://tinyurl.com/389ngn.  See how
> we reported the same flare at,
> http://www.arrl.org/w1aw/prop/2006-arlp051.html.  Our bulletin shows
> that the solar flux observatory in British Columbia also had
> problems from that event.
> 
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra@xxxxxxxxx
> 
> For more information concerning radio propagation, see the ARRL
> Technical Information Service at,
> http://www.arrl.org/tis/info/propagation.html. For a detailed
> explanation of the numbers used in this bulletin, see
> http://www.arrl.org/tis/info/k9la-prop.html. An archive of past
> propagation bulletins is at, http://www.arrl.org/w1aw/prop/ .
> Monthly propagation charts between four USA regions and twelve
> overseas locations are at, http://www.arrl.org/qst/propcharts/.
> 
> Sunspot numbers for May 31 through June 6 were 11, 41, 45, 58, 58,
> 63 and 47 with a mean of 46.1. 10.7 cm flux was 74.6, 79.4, 83.2,
> 87, 85.7, 88.8, and 87.1, with a mean of 83.7. Estimated planetary A
> indices were 4, 6, 7, 10, 8, 3 and 2 with a mean of 5.7. Estimated
> mid-latitude A indices were 2, 5, 5, 7, 8, 2 and 2, with a mean of
> 4.4.
> NNNN
> /EX
> 
> 
>

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