Monday, April 2, 2012

Recap - 10-Meter Activity Fall/Winter 2011-12

It was a special year after many years of a quiet lull in solar activity.
Thank you PropNET and see you all on Es this Spring.
73s Art Jackson KA5DWI

Charts Based On:
24,685 PropNET and Non-PropNET PSK31 Captures
Dates: September 23, 2011 - March 20, 2012
Grid Squares: 647
DXCC Entities: 83

Grid Square Equidistant Maps - North America and World

Seasonal Trends
Captures increased rapidly each progressive week of the fall. Trans-Equatorial propagation was strong at the end of August and southern Europe captures occurred by 9/04/11. Asian activity occurred by October. Activity peaked the week of 11/06 and rapidly declined until mid-December. It never was active throughout the remainder of the season.

10-Meter F2 activity was strictly a daytime phenomena. Once the sun rises activity takes off, soon after sunset it was gone. Most activity during evening and twilight hours is Es. The chart is shown in local standard time (Central) and a 3 hour average ( 7 AM is an average of 6,7,& 8 AM). The sun rose during my 7 AM hour and set during the 6 PM (18) hour.

Actual hourly experienced.

Solar flux had been steadily increasing since early July. It was at its highest in late October and early November (peaked near 180). Sadly, it continued to decline until the last three weeks of winter.
Blue line: Actual day
Dash line: 27 day running average
Red line: Polynomial trend-line

The chart of each day's sunspot number shows the trend more clearly.

The daily A-Index showed that the sun was very quiet (lack of storms) until the end of the winter.

The sharp increase and gradual decline was evident in the weekly charts.

The weekly sunspot number shows the steady decline in activity after the week of 11/06/11.

The weekly average A-Indices show a very quiet sun until the end of the winter.

The following chart displays the weekly PSK31 captures along with a polynomial trend-line. The trend-line shows the growth until 11/6/11, then a steady decline that never recovered the remainder of the season.

This chart shows the culprit for the lighter activity. Once solar flux hit about 140, captures were very high. As we got deeper into the entrance of Winter, a lack of sun and a declining solar flux below 140 cut down the opportunities.

Most captures below 1800 kilometers are probably Es. Unusual was that their captures follow the same trends as F2. Other years it was very afternoon and evening active. Captures from 2000 to 4000 kilometers were from the Carribean, Canada and the northeast and northwest corners of the USA, peaking early afternoon.

There is limited activity for 4000-6000 kilometers due to population. The distance is still important, Greenland and Alaska. Alaska was my 50th 10-Meter PSK31 captured state in October, all done in 18 months.
6000 to 8000 km captures involve western Europe, Iceland and a lot of Hawaii.

The 8,000 to 10,000 kilometer group includes northern and eastern Europe and the southern half of South America. This distance benefited when solar flux was very high during October and November. 10,000 to 12,000 km captures includes many Baltic republics, Ukraine, Belurus and Japan.

12,000 to 14,000 kilometer captures are mostly New Zealand and Australia. Most of the 14,000 plus are South Africa, but the farthest was western Australia.

There were some surprises. The charts are based on 60 degree increments centered in the direction noted.

Northerly paths are best at sunrise and sunset.

Northeasterly paths are best mid-morning.

Southeastern paths are best mid-afternoon.

Surprisingly, northwest paths are best just after the noon hour.

Southern paths are best late afternoon.

Southwestern paths are best before sunset.

Time Of Day
There are no surprises here. 10-Meters is a daytime band. The higher the sun, the more productive it is. The band gets quieter as you approach sunset.
The only time that evening hours are little active are during periods of Es.

A little Es activity can be seen in January and February, In November, high solar flux kept it open later into dusk.

Hourly Breakdown by Week of the Fall and Winter
There is not much change on opportunities once you are 6 weeks each side of the Winter Solstice. The only inconsistency is 4 weeks into Fall and the 4 weeks before Winter ends. The band opens at sunrise, peaks at noon and then closes at sunset.
Traces of Es can be seen by the evening activity bumps in January and February.

Conclusion in a nutshell.....
If you were asleep or under a rock in October and November, you missed a lot.
Pray for 150 plus Solar Flux next Fall.

I hope this will help your understanding of 10-Meter F2 opportunities.
Let the Es season begin!

Art Jackson KA5DWI
EM12ju near Cowtown, Texas

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