[South Florida DX Association] ARLP007 Propagation de K7RA

[Bill Marx]

> ZCZC AP07
> QST de W1AW  
> Propagation Forecast Bulletin 7  ARLP007
> From Tad Cook, K7RA
> Seattle, WA  February 18, 2005
> To all radio amateurs 
> 
> SB PROP ARL ARLP007
> ARLP007 Propagation de K7RA
> 
> Conditions improved this week over last. The average daily sunspot
> number rose nearly 34 points to 75.1, and the geomagnetic indices
> were down over the week. The geomagnetic field may become more
> active, and for February 18-20 the planetary A index is predicted at
> 20, 20 and 15. The major sunspot group affecting us this week will
> soon move off the visible solar disk, but there is a small sunspot
> group on the other side of the sun. Conditions should be fair to
> good for the ARRL International DX CW Contest this weekend.
> 
> Carl Luetzelschwab, K9LA has an interesting and useful propagation
> column in the March 2005 issue of WorldRadio. With ionosonde data he
> demonstrates how daily variations in solar flux have little effect
> on the MUF. Instead, propagation is better predicted with a smoothed
> sunspot number applied to seasonal variations.
> 
> For instance, this afternoon when I wanted a feeling for when 15 and
> 17 meters would still be open toward various locations, it was
> better to use W6ELprop with an average of sunspot numbers for the
> previous five days rather than today's solar flux. You can get the
> recent sunspot numbers from
> http://www.sec.noaa.gov/ftpdir/indices/DSD.txt, and download
> W6ELprop from http://www.qsl.net/w6elprop/.
> 
> This afternoon I went out to the car to do some 17 meter mobile
> work. Geomagnetic indices were low and the band was good. I had a
> nice CW chat with KG0TS in Des Moines, Iowa, and then worked
> 9Y4/YL2GM in Tobago on SSB. Juris was in the Caribbean getting ready
> for the DX contest from 9Y4W this weekend.
> 
> If you would like to comment or have a tip, email the author at,
> k7ra at arrl.net.
> 
> 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 February 10 through 16 were 63, 73, 72, 73, 115,
> 69 and 61 with a mean of 75.1. 10.7 cm flux was 114.1, 114.1, 116.4,
> 115.5, 118.1, 121.7 and 112.8, with a mean of 116.1.  Estimated
> planetary A indices were 17, 11, 5, 4, 5, 5 and 13 with a mean of
> 8.6. Estimated mid-latitude A indices were 11, 7, 3, 2, 4, 1 and 8,
> with a mean of 5.1.
> NNNN
> /EX
> 
>