Tuesday, December 25, 2012

Comparison 10-Meter Propagation Fall 2011 and 2012


Happy Holidays.
The Winter Solstice has passed and the world as we know it did not end.  If it had, the Sun was not going to be the cause of it.  Although we are in a period in Cycle 24 in which we should see a continuous rise in solar flux as we approach a peak next year, we are seeing quite the contrary. This cycle is showing to be weak and may have peaked very early.

Here is what we have seen since the Fall Equinox
on September 23.


For 2012, total captures are 60% less than what was experienced in 2011.
The first week of Fall for 2012 looked very promising as captures were slightly higher.  After one rotation of the Sun, totals came close to their 2011 counterpart during the week of 10/21.  Since that week, activity have been significantly lower each week since.
Captures were high the week of 10/21, have declined since.  Activity has been extremely low since the first week of December.

The highest volume of activity occurs between 1750-3500 kilometers, single hop F2.  From here it includes the east and west coasts, the Carribean islands and the top of South America. These volumes are down almost 70% from last year.
 
Removing the largest segment shows that longer distances are down, but not to the same extent.  Longer distances are down near 35%.

Hourly activity clearly displays the lack of morning transatlantic and single-hop F2 activity.  Afternoon activity is as high as morning.  Recently as solar flux declined, it is more dominant.

Solar Flux is down 26 points to an average of 120 in 2012.  Sunspots are down 43.  Clearly a decline in solar activity.
The current trend shows no upward swing in solar activity.  It is very quiet.

Now the good news.....
Despite the lower numbers, coverage is not that bad this year.

2011 Grids - 572
DXCC - 79
2012 Grids - 474
DXCC - 77
Not as many grids in 2012, but coverage to eastern Europe
was better.
2011
2012
The lack of and coverage of single-hop F2 and assisted Es is evident here in North America.
2011
2012

Affect of the Sun This Season: 
Using a program called W6ELProp, I have detailed the affect of Solar Flux on F2 propagation each week of the season in 2011 and 2012.

The Maximum Usable Frequency (MUF) is based on the average solar flux for the week detailed.  The other station is located approximately 2,650 kilometers to the Northeast and is the most efficient distance for 10-Meter F2 propagation.


MUF declines as we approach the Winter Solstice due to less availability of the Sun.  Two significant valleys are noticeable in 2012 (10/31-11/7 & 11/28-12/19). 
 The "Active Hours" chart are based on the probability of 10-Meter F2 propagation over 50% for a 30 minute segment. The result of lower solar flux is noticeable. For 5 weeks this year, propagation for distances at 2,650 kilometers was little to none on 10-Meters.  

Conclusion:
Take advantage of 10 Meters whenever Solar Flux rises above 120 and especially when it nears 140.  It looks like Cycle 24 is not going to be great, but opportunities are still there for a few years.

Enjoy the season and 73s
Art KA5DWI

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