[SFDXA] ARLP031 Propagation de K7RA
Bill Marx
bmarx at bellsouth.net
Fri Aug 5 18:14:28 EDT 2011
> ZCZC AP31
> QST de W1AW
> Propagation Forecast Bulletin 31 ARLP031
> From Tad Cook, K7RA
> Seattle, WA August 5, 2011
> To all radio amateurs
>
> SB PROP ARL ARLP031
> ARLP031 Propagation de K7RA
>
> Solar activity increased markedly this week, with the sunspot number
> rising to 130 on Monday, August 1, the highest since a reading of
> 131 on April 14, 2011. Average daily sunspot number more than
> doubled this week compared to last, rising nearly 54 points to 99.3.
>
> On Thursday I received a Significant Event Report from Rob
> Steenburgh, KA8JBY, Space Weather Forecaster at NOAA Space Weather
> Prediction Center:
>
> "A trio of significant active regions produced a series of radio
> blackout (solar flare) events in the past few days. To date, three
> radio blackouts reaching the R2 (Moderate) level have been observed.
> Earth-directed coronal mass ejections have been associated with each
> of the biggest radio blackout events on August 2-4. Solar radiation
> enhancements have also occurred in conjunction with each of these
> events, with the solar radiation storm event threshold being
> exceeded to reach the S1 (Minor) level in conjunction with the
> August 4 event".
>
> "Three coronal mass ejections (CMEs) are currently en route to
> Earth, with the commencement of geomagnetic storming expected early
> to mid-day on August 5 with the arrival of the CMEs associated with
> the August 2-3 events. The third of the string, seemingly the
> fastest CME, may catch up with the first two in the next 12-18
> hours, compressing the plasma and enhancing the embedded magnetic
> field. Storming levels are expected to attain G3 (Strong)
> conditions. The current Solar Radiation Storm may experience a kick
> with the shocks, and attain S2 (Moderate) thresholds".
>
> "Some level of geomagnetic disturbance is expected to continue
> through August 7 as the series of CMEs affect the Earth. Continued
> activity is likely from these regions as they continue to rotate off
> the visible solar disk over the next 7 days. The Space Weather
> Prediction Center will continue to monitor this event as it
> unfolds".
>
> Thanks, Rob!
>
> A NASA video shows a couple of the CMEs. Check
> http://www.nasa.gov/mission_pages/sunearth/news/News080411-dblpunch.html.
>
> The latest forecast on Thursday night has planetary A index for
> August 5-9 at 50, 30, 20, 15, and 10, then 8 on August 10-12, then
> 5, 8, 10, 15, 12, 10 and 8 on August 13-19. Solar flux predicted
> for August 5 is 115, 110 on August 6-7, 100 and 95 on August 8-9,
> then 85 on August 10-12, then 100 on August 13-16.
>
> The planetary A index at 50 is quite high.
>
> Geophysical Institute Prague predicts active conditions on August
> 5-7, unsettled to active August 8, quiet to unsettled August 9, and
> quiet conditions August 10-11.
>
> July is over, so let's look at some of the numbers. The average
> daily sunspot number for the month of July was 67.2, up from 55.5
> for June. The moving three month average of daily sunspot numbers
> for May through July, centered on June was 61.5. The 3-month moving
> average centered on January through June was 35.3, 55.7, 72.3, 74.4,
> 65.9 and 61.5.
>
> Vince Varnas, W7FA of Portland, Oregon wrote on July 30: "For the
> last week the ST0R DXpedition to South Sudan has had very weak
> signal strength here in the Portland area, particularly at night on
> the 17 meter band (18 MHz). Generally they are S-3, at best".
>
> "At 0209 UTC on July 30 there was a M9 solar flare from a big
> sunspot. At 0522 UTC I heard and worked the ST0R station on CW with
> much, much louder signal strength, both directions. (They were at
> the noise or slightly above a few hours earlier. When I worked them
> on SSB on July 26 at 2303 UTC they were about S-4.) They were S-8
> to 9 on the S-meter. The difference in signal strength between
> 'normal' and last night was about 30 db. Since it is a scientific
> fact that solar flares can and do enhance the reflectivity of the F
> layer, my conclusion is that this is what produced the markedly
> stronger signals from ST0R".
>
> Thanks, Vince.
>
> Sergej Ignatov, UZ2HZ of Kremenchug, Ukraine asked about a link to
> the Penticton source for thrice-daily solar flux readings, as the
> link he was using no longer works. Yes, they changed servers again,
> so the URL has changed. Try
> ftp://ftp.geolab.nrcan.gc.ca/data/solar_flux/daily_flux_values/fluxtable.txt
> in your web browser. The column you want is third from the right,
> the observed flux values, and the local noon (2000z) readings.
> Although readings are taken three times per day, the noon reading is
> the official solar flux for the day, also shown at
> http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt in whole number
> resolution.
>
> As geomagnetic conditions change over the next few days, you can
> check http://www.swpc.noaa.gov/ftpdir/indices/DGD.txt for the
> planetary K index, updated every three hours. You can also check
> out http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html every day
> after 2100z for an updated daily forecast of solar flux and
> planetary A index.
>
> Joe Molon, KA1PPV of Stamford, Connecticut writes: "Well it
> happened again. Not much happening southbound but this time the
> door to Europe was wide open.
>
> I had heard about the M Class flare and decided to check up on solar
> conditions because I knew it might get really good before it goes
> into the toilet. I saw a SF of 116 with an A Index of 3 and a K
> Index of 1 and that is all I needed.
>
> In one hour I logged IZ5RVG, DL2OCE, IC8TEM, IZ5MXA and EB5DZC.
>
> Not that unusual for someone running 100W into a beam but, as usual,
> I did it the hard way with 1.5 watts all on 20 meters. Got 599 on
> all except for the last when the noise crept up.
>
> I was using my Small Wonder Labs PSK kit for 20m with 1.5W into a
> Diamond BB7V 25 feet AGL. The propagation Gods opened the gate and
> I walked right through. Wow! It was great to get everyone that I
> tried for. That never happens in QRPland. Good DX. Yep! It's
> about time! Now watch the power grid get knocked out tomorrow when
> the CME shows up!"
>
> Thanks, Joe! Sounds like fun.
>
> 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://arrl.org/propagation-of-rf-signals. For an explanation of
> the numbers used in this bulletin, see
> http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of
> past propagation bulletins is at
> http://arrl.org/w1aw-bulletins-archive-propagation. Find more good
> information and tutorials on propagation at
> http://mysite.ncnetwork.net/k9la/index.html.
>
> Monthly propagation charts between four USA regions and twelve
> overseas locations are at http://arrl.org/propagation.
>
> Instructions for starting or ending email distribution of ARRL
> bulletins are at http://arrl.org/bulletins.
>
> Sunspot numbers for July 28 through August 3 were 84, 88, 101, 128,
> 130, 98, and 66, with a mean of 99.3. 10.7 cm flux was 107.3,
> 111.7, 112.7, 118.6, 124.9, 121.6, and 119.9, with a mean of 116.7.
> Estimated planetary A indices were 3, 5, 16, 8, 9, 3, and 3, with a
> mean of 6.7. Estimated mid-latitude A indices were 3, 3, 10, 7, 6,
> 3, and 3, with a mean of 5.
> NNNN
> /EX
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