[South Florida DX Association] ARLP013 Propagation de K7RA

[Bill Marx]

 SB PROP ARL ARLP013
> ARLP013 Propagation de K7RA
> 
> We saw a decline this week in average daily sunspot numbers and
> solar flux. Average daily sunspot numbers were down over 10 points
> to 34.1 when compared to the previous week, and average daily solar
> flux declined almost 12 points to 80.2.
> 
> The short term prediction shows solar flux values rising slowly over
> the next week, reaching 100 around April 8. The planetary A index
> should rise over the next few days. The predicted planetary A index
> for April 2-5 is 15, 25, 35 and 20.
> 
> Just completed is the first quarter of 2005. Now is a good time to
> take some running averages of sunspot numbers and solar flux,
> comparing this quarter to previous periods.
> 
> From the first quarter of 2003 through the first quarter of 2005,
> the average daily sunspot numbers were 120.3, 107.3, 110.2, 99.2,
> 72.9, 71.3, 69.3, 61 and 46.1.
> 
> The average daily solar flux for the same period was 134.3, 124.2,
> 120.8, 137.4, 111.1, 99.5, 111, 104.8 and 96.4.
> 
> We see clearly that cycle 23 continues the fall toward solar
> minimum, which is currently forecast roughly around October 2006 to
> April 2007. Fortunately, the rise of a solar cycle is much more
> rapid than its decline. But when comparing current smoothed sunspot
> numbers to the predicted numbers once the next cycle turns up, the
> predicted value for April 2005 is just slightly above the predicted
> value for December 2007. So we shouldn't expect conditions to
> improve beyond what we've had recently until early 2008, or a little
> less than three years from now. Current sunspot numbers are lower
> than they've been since 1997. The peak of the next cycle will
> probably occur in 2010.
> 
> March 1965 was 40 years ago. I was still twelve years old, and when
> riding the school bus home one day in that March, I saw that my mom
> had hung her red sweater in the window. That was my signal. I
> couldn't wait for the bus to drop me off so I could race back up the
> hill. I ran into the house, grabbed the envelope from the FCC off
> the dining room table, and ripped it open. Inside, there was my new
> Novice call, WN7CSK. Hard to believe it's been 40 years.
> 
> If you would like to comment or have a tip, email the author at,
> k7ra at arrl.net.
> 
> For more information concerning radio 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 March 24 through 30 were 57, 65, 41, 35, 15, 15
> and 11 with a mean of 34.1. 10.7 cm flux was 87.1, 82.1, 77.7, 78.4,
> 79.7, 78.8 and 77.6, with a mean of 80.2. Estimated planetary A
> indices were 6, 18, 16, 13, 4, 5 and 9 with a mean of 10.1.
> Estimated mid-latitude A indices were 4, 15, 12, 8, 2, 3 and 6, with
> a mean of 7.1.
> NNNN
> /EX
> 
>