[South Florida DX Association] ARLP012 Propagation de K7RA

[Bill Marx]

> 
> SB PROP ARL ARLP012
> ARLP012 Propagation de K7RA
> 
> Seasonally this is a great time for HF propagation, as the Northern
> Hemisphere passed into spring last Sunday.  But sunspot activity is
> low as we slip toward the bottom of the cycle, still estimated at
> nearly two years away.
> 
> The weekly average of the daily sunspot number slipped over 16
> points from last week to 44.3.  The daily average of solar flux was
> down over 12 points to 92.1.  Geomagnetic A and K indexes showed
> stable conditions, but slightly unsettled on March 19.  There were
> many periods with the K index at zero or one, even at high
> latitudes.  For the entire day on March 22, the College K index from
> Fairbanks, Alaska was zero, which produced an A index for that day
> of zero.  This was even slightly lower than the planetary or
> mid-latitude values for that day.
> 
> The forecast for this week shows more of the same, with solar flux
> slipping below 90.  A solar wind stream may cause some unsettled to
> active conditions.  The U.S. Air Force shows unsettled to active
> conditions with a planetary A index around 15 for March 27-29.  RWC
> Prague shows unsettled to active conditions for March 26 and 27,
> with unsettled conditions for March 25, 28 and 29.
> 
> Noel Petit, WB0VGI, sent a link to a magnetometer in Minnesota which
> is on a rural farm north of Minneapolis.  The approximate location
> is northwest of Cambridge, Minnesota at 45.616 degrees N, 93.312
> degrees W.  You can observe the output in terms of K index from a
> server at Augsburg College at
> http://space.augsburg.edu/ucla/Pictures/kIndex.png.  This is similar
> to a K index from NOAA generated by 9 magnetometers in North America
> at http://www.sec.noaa.gov/rt_plots/kp_3d.html.  
> The Cambridge K index gives a nice localized indication of real time 
> geomagnetic activity at that latitude in the upper Midwest.
> 
> Reminiscence of the late 1950s and the peak of cycle 19 continues to
> generate email.  I'll let John Goewey, KI5IG of New Mexico tell it:
> 
> ''During that peak K2UKN (Charles Groves) had a regular schedule with
> JAs every noon time on 6 meters. I DXed a YL on 6 meters in MO while
> I was WA2AJM in NJ. The YL had a curtain rod out the window, she
> said. Another unusual contact was off my light bulb dummy load, in
> the basement shack. QSO was 20 miles away, 6 meters as well. Yes, I
> thought it was always going to be that way also.''
> 
> Emory Gordy, W4WRO was only 13 until the end of 1958, and writes, ''I
> was first licensed in 1958, the era of the BIG ONE. Being a
> novice-neophyte I, like others, innocently thought it would last
> forever. The fact that it hasn't been repeated didn't dampen my
> enthusiasm for ham radio''.
> 
> And last, Peter Hansen, W8TWA wrote: ''Having started my ham radio
> activity as a Novice in 1954, I have seen the best and worst several
> times now. One thing I miss is the two weekend ARRL DX contest.
> Since the two weekends were separated by about a month, the March
> weekend seemed to be a bit more exciting as we approached the
> equinox. The two weekend contest was a great opportunity to observe
> the changing conditions as winter came to a close. Maybe it was my
> imagination, but it always seemed easier to work the polar path,
> both long and short, to VU, UL, UH, UM, etc (excuse the old prefix
> references.) in March than it was in February. And while there were
> obvious variations in geomagnetic activity and availability of
> stations between the two weekends, it always seemed that March was
> better for that path. However, another contributing factor could
> have been that we spent more time listening because many of the
> stations had already been worked on the first weekend. To this day I
> continue to monitor the flux, A, and K indices before the contest,
> and find it of interest how that nuclear furnace 93 million miles
> away continues to affect our everyday living, as well as its
> influences on our hobby''.
> 
> 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 17 through 23 were 35, 37, 41, 39, 53, 49
> and 56 with a mean of 44.3.  10.7 cm flux was 101.4, 96.5, 93, 89,
> 89.7, 87.3 and 87.7, with a mean of 92.1.  Estimated planetary A
> indices were 12, 9, 14, 5, 8, 3 and 4 with a mean of 7.9.  Estimated
> mid-latitude A indices were 8, 6, 9, 4, 5, 2 and 3, with a mean of
> 5.3.
> NNNN
> /EX
>