[South Florida DX Association] ARLP032 Propagation de K7RA

[Bill Marx]

 ZCZC AP32
> QST de W1AW  
> Propagation Forecast Bulletin 32  ARLP032
> From Tad Cook, K7RA
> Seattle, WA  August 11, 2006
> To all radio amateurs 
> 
> SB PROP ARL ARLP032
> ARLP032 Propagation de K7RA
> 
> On four days this week the sun was spotless, so the average daily
> sunspot number for the week dropped over 11 points to 8.6.  Sunspot
> numbers are now recovering and climbing, from zero on Monday to 12,
> 25 and 37 on Tuesday through Thursday.  Sunspot numbers and solar
> flux should continue a modest recovery through next week.  When the
> sunspots were zero, the solar flux (a measurement of 10.7 GHz energy
> from the sun, observed at a station in British Columbia) was below
> 70.  Now solar flux is expected to rise in the short term to 85 or
> more.
> 
> Rising sunspot numbers and solar flux mean higher MUF (Maximum
> Usable Frequency), although not a lot higher.  For instance, using
> propagation prediction software, for today with zero sunspots, the
> MUF over the path from Philadelphia to Germany would go above 17 MHz
> from 1430-2230z, to a maximum of 17.6 MHz.  But with an average
> sunspot number of 40, the MUF over the same path rises above 19 MHz
> from 1400-2230z, peaking at 19.8 MHz.  If the sunspot number were
> 120 instead, a figure we won't observe for a few years, the MUF
> would rise above 23 MHz from 1430-2130z, peaking at 23.8 MHz.  The
> difference on those three scenarios would be whether 20 meters, 17
> meters, or 15 meters is the highest practical band to use.
> 
> With existing conditions as they are, that path to Germany would be
> best on 17 meters from 1230-0000z, with stronger signals toward the
> end of that period, but the best chances for an opening around
> 1730-2100z.  20 meters should have slightly stronger signals, with
> openings beginning weakly around 1130z and signals gradually
> increasing to 0200z, and the signals falling off afterward.  Best
> bet would be 2130-0100z on 20 meters.
> 
> Compared to a month ago, operators at each end of that path would
> notice a much stronger chance of a 17-meter opening, and a much
> earlier closing of 20 meters, with the days getting shorter as we
> move toward the fall equinox.
> 
> Similarly, a month's difference on the West Coast to Japan path
> would see the rise of 15 meters as a viable choice from 2130-0200z.
> Moving toward fall, 20 and 17 meters would close a little earlier,
> while 30 and 40 meters would each open about an hour or more
> earlier.
> 
> Steve Rasmussen, N0WY of Plattsmouth, Nebraska is the contest
> manager for 10-10 International (see http://www.ten-ten.org/) and he
> says ten meters had great openings after sunrise and after dusk
> during the 10-10 contest last weekend.  He worked 151 stations,
> mostly to the east and southeast. N2EOC (with an exceptional 10
> meter antenna, says Steve, although he didn't say what N2EOC is
> using) in New Jersey worked 255 stations.  Steve says, ''WN4AMO in
> Florida did 259 and AH6RF in Hawaii made 184.  KK7UU in Oregon ended
> up with 146.  The band is NOT dead. You just have to be there when
> it is open.''
> 
> W4HLR, Howard Runions of Newbern, Tennessee says he got cards from
> F8DBF and HI3TEJ for his 3 watt 50.115 MHz SSB contacts on July 17.
> He is thrilled with the cards, naturally.
> 
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra at arrl.net.
> 
> 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/ .
> 
> Sunspot numbers for August 3 through 9 were 23, 0, 0, 0, 0, 12 and
> 25 with a mean of 8.6. 10.7 cm flux was 71.3, 69.6, 69.5, 69.5,
> 69.8, 71.4, and 74.1, with a mean of 70.7. Estimated planetary A
> indices were 6, 3, 4, 4, 32, 12 and 9 with a mean of 10. Estimated
> mid-latitude A indices were 5, 2, 2, 2, 19, 10 and 9, with a mean of
> 7.
> NNNN
> /EX
>