[South Florida DX Association] ARLP022 Propagation de K7RA

[Bill Marx]

 SB PROP ARL ARLP022
> ARLP022 Propagation de K7RA
> 
> Thanks to Carl Luetzelschwab, K9LA for writing an excellent
> propagation bulletin last week while your regular reporter was
> traveling.
> 
> Solar activity continues to be low as we head toward the bottom of
> the sunspot cycle. Still, we haven't seen weeks on end with no
> sunspots, so I suspect the minimum is not quite here.
> 
> Let's take a look at the monthly averages of sunspot numbers and
> solar flux for May, compared with the past year.
> 
> The average daily sunspot numbers for the months May 2005 through
> May 2006 were 65.4, 59.8, 68.7, 65.6, 39.2, 13, 32.2, 62.6, 26.7,
> 5.3, 21.3, 55.2 and 39.6. Average daily solar flux for the same
> months was 99.5, 93.7, 96.5, 92.4, 91.9, 76.6, 86.3, 90.8, 83.4,
> 76.5, 75.5, 88.9 and 80.9.
> 
> With fewer sunspots, the higher frequencies aren't as useful. There
> is a direct correlation between MUF (Maximum Usable Frequency) and
> the number of sunspots. That's why at the peak of a solar cycle 10
> meters is much more usable than at the bottom of the cycle.
> 
> We received several emails this week about sporadic-E propagation.
> This is when unpredictable ionized clouds form in the lower E-layer
> of the ionosphere and provide interesting and exciting long range
> propagation. June is a very good month for this in the Northern
> Hemisphere. Broadcast television DXers such as Mike Shaffer, KA3JAW
> in Tampa report regularly receiving TV broadcasts from stations in
> Mexico and Central America. Paul Gray, N0JAA in east-central Florida
> reports working 12 meter sporadic-E from time to time into Virginia
> and New York
> 
> 6 meters also can be exciting. Bill Van Alstyne, W5WVO of Rio
> Rancho, New Mexico writes, "Sporadic-E season is upon us, and
> yesterday (Sunday, May 28) saw one of the best 6-meter North
> American sporadic-E openings of the past few years. At one point
> late Sunday morning, 6 meters was open coast-to-coast, with QSOs
> between CA and the east coast via long double-hop propagation (or
> maybe triple-hop in some cases) taking place frequently. Here in New
> Mexico, I was hearing and working both coasts and pretty much
> everything in between with S9+ signals."
> 
> Bill continues, "Many stations in the eastern part of the country,
> and even out west here, worked a lot of DX in the Caribbean and
> Central America, but my path in that direction is poor, and I didn't
> hear any of it."
> 
> He goes on to say, "I did pick up a number of new grid squares,
> though, including EL94 (Florida Keys) on a double-hop path and a
> cool backscatter contact with DM34 in central Arizona. Backscatter
> is unusual on 6 meter sporadic-E (in my experience). My theory is
> that a typical sporadic-E cloud is much more planar a refractive
> medium than the F2 layer, and doesn't scatter energy as much in
> off-beam directions. Thanks to W7MHW for hearing my weak signal
> through the pile-up of S9+20 signals from the southeast states."
> 
> Bill continues with, "Heard several guys talking about sporadic-E on
> 2 meters, but I think it was pretty limited. I didn't hear any
> really super-short skip on 6 meters; my guess, from the minimum skip
> distances I was hearing, is that the Es MUF was somewhere around
> 100-120 MHz--at least in these parts."
> 
> For the next few days, it looks like solar wind from coronal holes
> could be mildly disruptive. The planetary A index forecast for June
> 2-3 is 20, then settling down to quiet conditions a couple of days
> later. Average daily sunspot numbers were up this week over last,
> and are expected to rise slightly over the next few days. Higher
> sunspot numbers mean higher MUFs, but 20 meters should still be your
> best band for reliable worldwide propagation.
> 
> For instance, California stations can work Japan on 20 meters
> currently around 0600-1600z, while the best 20 meter opening to
> Australia should be 0630-1300z. If you are in Georgia, the best 20
> meter opening to Europe should be around 2230-0200z and 0430-0830z.
> 
> But you can work out your own paths to any location. Just use the
> suggestions in an earlier Propagation Forecast Bulletin, ARLP014,
> seen on the web at, http://www.arrl.org/w1aw/prop/2006-arlp014.html.
> 
> 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 May 25 through 31 were 33, 51, 69, 78, 54, 51
> and 44 with a mean of 54.3. 10.7 cm flux was 83.7, 81.6, 83, 84.7,
> 81.1, 80, and 78.4, with a mean of 81.8. Estimated planetary A
> indices were 5, 5, 3, 7, 3, 9 and 6 with a mean of 5.4. Estimated
> mid-latitude A indices were 4, 1, 1, 5, 1, 7 and 4, with a mean of
> 3.3.
> NNNN
> /EX
>