[IRCA] Fw: ARLP033 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, August 10, 2007 1:23 PM
Subject: ARLP033 Propagation de K7RA


> SB PROP @ ARL $ARLP033
> ARLP033 Propagation de K7RA
> 
> ZCZC AP33
> QST de W1AW  
> Propagation Forecast Bulletin 33  ARLP033
>>From Tad Cook, K7RA
> Seattle, WA  August 10, 2007
> To all radio amateurs 
> 
> SB PROP ARL ARLP033
> ARLP033 Propagation de K7RA
> 
> Average daily sunspot numbers were up a little, rising over five
> points to 12.4.  After a short period of no sunspots, we are back to
> seeing a spot or two every day.  Expect these conditions to
> continue, possibly falling back to zero spots again around August
> 16-20.
> 
> Today (August 10) expect some unsettled to active geomagnetic
> conditions due to a solar wind stream.  Planetary A index predicted
> for August 10-16 is 25, 15, 5, 5, 5, 5 and 10.  Geophysical Institute
> Prague predicts unsettled to active conditions August 10, quiet to
> unsettled August 11, quiet August 12-14, quiet to unsettled August
> 15, and unsettled August 16.
> 
> New predictions for smoothed sunspot numbers in coming months seem
> to appear almost monthly from the Space Environment Center.  Now the
> estimate for smoothed sunspot number in December 2007 has risen from
> 21 to 24.  You can see the prediction from last month at
> http://www.sec.noaa.gov/weekly/pdf/prf1661.pdf and the current one
> at http://www.sec.noaa.gov/weekly/pdf/prf1666.pdf . Look on page
> nine of both issues.
> 
> Bob Wertz, NF7E was operating in Alaska last month, and wrote asking
> about some strange conditions he observed on the air.
> 
> ''Recently while on a mini DXpedition on Ushagat Island, located off
> the coast of Homer, Alaska, we encountered some strange lulls in
> operating.
> 
> ''We landed on the island on July 12, and after about 3 hours, we
> were on the air and doing great.  Then on the following few days, we
> almost lost all communications with the world.  At first we thought
> it was rig problems, then antenna problems, but then realized it
> must be poor propagation.
> 
> ''Can you give me some input about conditions those days?''
> 
> Yes, we can.  Looking at data from the magnetometer at University of
> Alaska, we see that the A index (called the College A index) on July
> 11-16 was 32, 10, 2, 39, 19 and 7.  The cause was solar wind, and
> the disturbance tends to concentrate toward the poles, so the
> absorption in Alaska from this activity can lead you to believe your
> radio is dead. Folks operating at high latitudes have had a respite
> from this activity because during a lull in the solar cycle, the
> chance of geomagnetic storms is much less.  But old Alaska hands will
> tell you of times in years past when geomagnetic storms seemed to
> last for months, and HF was mostly unusable.  That is the downside
> of higher solar activity.  We like sunspots, because of the
> accompanying increase in reflection and refraction in the
> ionosphere.  But along with that comes greater chance of geomagnetic
> storms.
> 
> 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 August 2 through 8 were 0, 11, 11, 11, 16, 13
> and 25 with a mean of 12.4.  10.7 cm flux was 69.4, 70.4, 69.4, 68.9,
> 70, 69, and 69, with a mean of 69.4.  Estimated planetary A indices
> were 5, 4, 2, 2, 12, 23 and 6 with a mean of 7.7.  Estimated
> mid-latitude A indices were 5, 4, 0, 2, 8, 23 and 5, with a mean of
> 6.7.
> NNNN
> /EX
> 
>

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