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Last update: Friday, 30-Jul-2021 03:33:18 GMT
SB PROP @ ARL $ARLP031
ARLP031 Propagation DE K7RA
QST DE W1AW
Propagation Bulletin 31 ARLP031 From Tad Cook, K7RA
Seattle, Washington July 30, 2021
To all radio amateurs
Solar activity slowed this week. Average daily sunspot number declined to 33.9 this week (July 22-28) from 48.9 in last week's report. Wednesday July 28 had no sunspots at all.
Average daily solar flux went from 81.3 to 83.
Geomagnetic indicators held steady, with average daily planetary A index at 6.4 both last week and this week. Average daily middle latitude A index went from 6.4 last week to 6.3 this week.
Predicted solar flux is 76 on July 30-31, then 74 on August 1, 72 on August 2-4, 74 on August 5-6, 75 on August 7- 12, then 78, 80, 82 and 85 on August 13-16, 90 on August 17-18, 85 on August 19-20, 80 on August 21, 82 on August 22-28, 78 on August 29, and 75 on August 30 through September 8.
Predicted planetary A index is 8, 12 and 8 on July 30 through August 1, 5 on August 2-9, 12 and 10 on August 10-11, 5 on August 12-15, 10 and 8 on August 16-17, 5 on August 18-23, then 12, 12 and 8 on August 24-26, 5 on August 27-28, 8 on August 29, and 5 on August 30 through September 5.
F.K. Janda, OK1HH is on vacation this week hiking in the mountains of the Czech Republic, so we have forecasts from two of his associates.
"Solar activity forecast for the period July 30 - August 05, 2021
Activity level: mostly very low X-ray background flux (1.0-8.0 A): in the range A5.5-B1.5 Radio flux (10.7 cm): a fluctuation in the range 74-82 Events: class C (0-4/period), class M (0/period), class X (0/period), proton (0/period)
Relative sunspot number (Ri): in the range 0-55
Martina Pavelkova RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic e-mail: sunwatch(at)asu.cas.cz"
"Geomagnetic activity forecast for the period July 30 - August 05, 2021
Quiet: Jul 30 - 31, Aug 2 - 4 Unsettled: Jul 31, Aug 1 - 3, 5 Active: 0 Minor storm: 0 Major storm: 0 Severe storm: 0
Geomagnetic activity summary:
Next week, we expect at most quiet to unsettled conditions. The more unsettled events are possible about August 1 - 2, and also about Thursday, August 5.
The other days, we expect quiet to unsettled conditions generally, closer to quiet level.
Tomas Bayer RWC Prague Institute of Geophysics of the ASCR, Prague Department of Geomagnetism Budkov observatory (BDV)"
"There was a big 2m Es opening from DN70 to the Midwest this afternoon, July 24. I was busy with some chores then happened to look at DXMaps and the APRS VHF propagation map and noticed a large Es cloud located over eastern NE/western IA and another located over SE KS. I quickly tuned into 2m FT8 144.174. Signals were very strong, with +21 db the best report I sent and +29 the best report I received. My QSOs, beginning at 2216z and ending at 2235 UTC were as follows:
WA9DU EM69 WB8ART EM79 AA9JS EN51 KC9IKB EM69 KA9CFD EN40 WA4CQG EM72 KX9X EN50 NY1V EM69 KM8V EN91 K2DRH EN41 AG4V EM55 KO9A EN52 WB8JCW EN80
Then followed 26 minutes of a mixture of single decodes, total quiet, meteor bursts, but no QSOs. Then at 2301 UTC:
And then it was over. I don't know when the opening began since it was well and truly in progress when I got to the radio, but it was an amazing 20 minutes or so.
Unfortunately I was unable to complete with W3IP in FM19, which would have been the longest distance QSO of the opening for me. We heard each other over several sequences but were unable to finish the exchange.
My station: Kenwood TS-2000, Beko HLV-1000 running at 750W, 10 element LFA (by G0KSC) at 35 feet.
73 - Jan, KC0V"
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of 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. More good information and tutorials on propagation are at http://k9la.us/.
Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .
Sunspot numbers for July 22 through 28, 2021 were 77, 46, 35, 24, 25, 25, and 0, with a mean of 33.1. 10.7 cm flux was 89, 87.4 83.9, 81.6, 80.8, 79.6, and 78.8, with a mean of 83. Estimated planetary A indices were 11, 4, 4, 3, 4, 6, and 13, with a mean of 6.4. Middle latitude A index was 9, 3, 5, 5, 3, 6, and 13, with a mean of 6.3. NNNN
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