[South Florida DX Association] ARLP031 Propagation de K7RA

[Bill Marx]

ZCZC AP31
> QST de W1AW  
> Propagation Forecast Bulletin 31  ARLP031
> From Tad Cook, K7RA
> Seattle, WA  July 30, 2004
> To all radio amateurs 
> 
> SB PROP ARL ARLP031
> ARLP031 Propagation de K7RA
> 
> Sunspot 652 has rotated out of view, but it was the source of major
> excitement this week.  Coronal mass ejections caused big geomagnetic
> storms on Sunday and Tuesday, July 25 and 27.  The planetary A index
> was 122 on Sunday, 31 the next day, and 162 on Tuesday.  This caused
> radio blackouts on the HF bands, but was a real blast for 6-meter
> operators who reported great openings.  The activity was enhanced by
> a south-pointing interplanetary magnetic field, leaving the earth
> vulnerable to blasts of energy from the sun.
> 
> Aurora displays accompany periods of high geomagnetic activity, but
> they tend to predominate at higher latitudes.  The stronger the
> activity, the higher the K and A index, and the further south that
> northern lights can be seen.  We're used to seeing photos of aurora
> from Alaska, especially above the Arctic Circle, but at
> http://science.nasa.gov/spaceweather/aurora/images2004/27jul04/Mammana1.
> jpg
> you can view a photo taken July 27 at Borrego Springs in California.
> This is only 20 miles north of the 33rd parallel, in Southern
> California.
> 
> Marc Weinberg, K9PET, sent a note about being maritime mobile in
> Svalbard as JW/K9PET last week.  He was north of the 79th parallel,
> and when geomagnetic disturbances hit, he said he ''thought the world
> had disappeared''.  You can see a photo (taken from a distance) of
> him operating on land from Raudfjorden Spitsbergen on July 20th.  Go
> to www.expeditions.com and search for the photo accompanying the DER
> (Daily Expedition Report) for the M S Endeavour for July 20th.  In a
> few week's Marc will have more photos on his own web site,
> www.casualdx.com.
> 
> Michael Tracy, KC1SX, sent in an interesting link for a Macromedia
> Flash movie on HF propagation by AE4RV.  Watch it at
> http://www.ae4rv.com/tn/propflash.htm.
> 
> Over the next few days expect unsettled to active geomagnetic
> conditions, and declining sunspot and solar flux numbers.  Predicted
> planetary A index for Friday through Monday, July 30 through August
> 2 is 30, 20, 20 and 8.  Predicted solar flux for those same days is
> 95, 90, 85 and 90.  Solar flux is expected to peak again at about
> 125 around August 14-18.  More sunspot activity is ahead, at least
> for the near term.
> 
> For more information concerning propagation and an explanation of
> the numbers used in this bulletin see the ARRL Technical Information
> Service propagation page at
> http://www.arrl.org/tis/info/propagation.html.
> 
> Sunspot numbers for July 22 through 28 were 117, 86, 109, 130, 113,
> 66 and 66 with a mean of 98.1.  10.7 cm flux was 172.9, 165.1,
> 147.2, 156.2, 128, 118.1 and 100.7, with a mean of 141.2.  Estimated
> planetary A indices were 19, 47, 27, 122, 31, 162 and 14, with a
> mean of 60.3.  Estimated mid-latitude A indices were 13, 21, 29, 64,
> 26, 119 and 11, with a mean of 40.4.
> NNNN
> /EX
>