Saturday, January 23, 2016

How Solar Cycle 24 Affected 10-Meter Spring/Summer Es

Please reference the PropNET Studies Blog and Art Jackson-KA5DWI if this material is used in a presentation or publication.  Thank you.

In 2004, I first dabbled with PropNET on 10-Meters, if I recall using UI-View and MultiPSK. Back then, a Catch report was generated to create an “hour by hour” – “day by day” historical record of captured PropNET PSK31 captured packets, as well as a listing of transmissions that failed to acquire a captured status.  I was impressed with the results in 2004 and decided to do a full-time PropNET effort in 2005 for what I call the “Spring/Summer Sporadic Es” season.

“Es” had always fascinated me over my 25 years as a ham and quite a few years prior to becoming one. I was an avid SWL, TV, AM/FM broadcast, VHF/UHF Utility DX’er. I am sorry to admit, a CB’er prior to the “Good Buddy” days.  I had experienced a number of unique events during the spring and summer on these frequencies. Once I became a Ham, I was more interested in trying to figure out what might be behind it.
I am a numbers person. I worked in the banking business for almost 30 years and after the industry was deregulated, decided that I needed to take my basic math talents to something more worthwhile, education. A co-worker described me as someone you ask what time it is, and I would tell you how the clock works. I felt that there had to be mathematical patterns to explain the phenomena. PropNET had a chance to help me identify them.

I do not believe in Magic.
Everything happens for a logical, mathematical and scientific reason. Given the right conditions and sampling of data, anything can be explained by numbers. So the quest to find to find answers to Sporadic Es began in 2005.  The journey was worth it.

After the first year I figured out that my own premonitions and theories needed some correcting. After analyzing each year, I would make the necessary adjustments to perfect the next year’s analysis. One year turned into two, two turned into three and so on. After accumulating three years of data I was able to apply statistical trend-lines (lines of best fit) to the 10-Meter Spring/Summer Es phenomena. By year five, I submitted my first paper on Es propagation to the Central States VHF Society Conference (CSVHFS). Year six, I submitted a second paper to the CSVHFS Conference and was the opening presenter at the meeting.  At that time I was beginning the finishing touches to the seventh and final year of my study of 10-Meter Sporadic Es.

At that 2011 CSVHFS Conference (last weekend of July), the next presenter was Jim Kennedy, K6MIO/KH6. Jim is an astrophysicist and is well known for his analysis of many events that have occurred on 6-Meters. In his presentation, Jim enlightened us to what appeared to be happening at the beginning of Solar Cycle 24.  The news was not very good.  Jim said that the geomagnetic poles of the Sun that swap during a solar cycle were not in sync. This would result in a poor peak of Solar Cycle 24 and would limit F2 opportunities on 6 Meters. I was a bit disappointed, but I figured I would always have Es to make up for the lost F2 opportunities.  Or so I thought…….

So this is where we begin our last analysis. By the summer of 2011, I was already seeing some changes that were foretelling the future.

Solar Cycle 23 and 24:
The graphs show the extent of the decline and bottom of Solar Cycle 23 and the rise, peak and decline of Solar Cycle 24.

It is beginning to appear that in the modern day measurement of solar cycles are showing that most of them have dual peaks. Cycle 23 peaked in July 2000 and again September 2001.  Cycle 24 peaked in November 2011 and once again in April 2014. As noted by the graphs, Cycle 24 was much weaker than Cycle 23.  Maximum usable frequencies were rarely higher than 40 MHz and 6 Meter F2 propagation was extremely rare.  Also, Cycle 23 declined for 9 years. The average decline is 7 years.
The next graph shows the Ap Index progression during the same period. This index shows geomagnetic activity and is similar in purpose to the K-Index. It is more quantitative that the K-Index and updated historically once a day.

For Solar Cycle 23, the Ap index peaked 2 years after the second peak of solar flux.  As of today, it has shown no indication of a decline for Cycle 24. The current level is near to the value experienced in 2005.

The Seven-Year Study:

I was very lucky to have started it in 2005. As we will learn later, to have been in a long decline towards the bottom of the solar cycle, followed by a low increase of solar activity appears to have allowed very consistent results year to year. As mentioned earlier, within 3 years all the statistical trend-lines were consistent to the very end of the study.

The study was a compilation of my captures of other PropNET participants from April 25 – August 15 (later 28th), eight weeks each side of the Summer Solstice.

My total number of PropNET captures for 7 years was 88,195, about 12,600 per year.
The study showed that the peak of the Spring/Summer Es season is clearly near the Summer Solstice. The trend-lines showed the peak on June 23rd or 24th. The median (the middle one) PropNET capture and active hour was on June 21, the solstice.

Es propagation is a daytime phenomenon, called diurnal.  Es can occur at any time, but once the Sun sets, activity and probabilities decline sharply. The most active and intense time for Es is mid to late morning. After a lull mid-afternoon, a second peak occurs before sunset. During the late afternoon, the distance of Es lengthens (multi-hop) as well as the absolute shortest distances (backscatter) occur.

Changes at the Home QTH and PropNET:
After 7 years computing my data, changes were to naturally occur.  After the 2009 season, the 10 Meter operating frequency was changed from the high end of PSK31 activity to just below it allowing the capture and recording of Non-PropNET (NPN) activity. After the 2011 season, I lowered my tower and reconfigured the antenna arrangements. The result was a higher noise level.  A new version of PropNET was released and overall, its performance was inferior to the prior version. The user had very limited control of the IMD channels and the program had operating issues if left running more than 2 days.  I would not transmit packets unless I was near the rig. I did not operate PropNET whenever on vacation trips.  Finally, I was inactive two-thirds of 2014 as I retired and moved to Arizona (DM34). 

Despite my issues, there were many other fine PropNET participants who were active during my absence.

All further data charted will reflect all PropNET and Non-PropNET 10-Meter captures from North American PropNET participants between June 1 and July 9, 2009 through 2015.  The range measured is 39 days around the Summer Solstice.

Solar Cycle 24 Begins:
Each of the following charts are the average recorded values between June 1 and July 9 of the year noted.

In 2009, solar flux was at minimum levels (67). By 2010, it was slowly increasing.  Solar flux began to surge during 2011 and peaked late that year. Solar flux remained high in 2012. Many thought the peak had occurred as it dipped in 2013, but resurged to the highest spring/summer level in 2014. It finally had begun its decline in 2015.

Background X-Ray flux is the average daily X-Ray flux experienced each measurement period. It is a numeric interpretation of Alpha/Numeric values (A0.0=0, B1.0=10, C1.0=19). The sun was spotless most of 2009.

The A-Indices indicate geomagnetic activity. As noted earlier for the past solar cycle, this activity tends to peak a couple of years after the final peak of solar flux.

At least one of these solar or geomagnetic indices increased year following the 2009 lull.

PropNET 10-Meter Capture Activity
The charts were quite conclusive.

In 2009, PropNET 10M operations were on 28.131 MHz, 11 kHz above the majority of regular PSK31 activity. Late 2009, the operating frequency was changed to 28.1186 MHz, 1.4 kHz below the activity. Thanks to Dave Donnelly’s KF6XA routines, this allowed for the capture of Non-PropNET activity surrounding 28.120 MHz. Non-PropNET activity accounted nearly 20% more captures in 2010.  Therefore if Non-PropNET captures had occurred in 2009, the total captures that year would be been near 90,000.  My personal PropNET statistics showed a decline of PropNET captures of 6% between 2009 and 2010. 

The next graph shows a steady decline of capture activity since 2009.
PropNET activity between June 1 and July 9.
For the above chart, 2009 and 2015 data was removed.
10-Meter PropNET activity declined from 2010 to 2015 at an “exponential” rate. For non-math people, in science and nature, growth and decline occurs exponentially. If the data precisely fits the trend-line equation, the coefficient of determination (R-Squared) value would equal to one (1).  In this case, 0.9538 is not bad at all.

A more simple description shows that in 2009 if a PropNET station transmitted a PNP packet or a Non-PropNET station transmitted a CQ, ten (10) PropNET participants captured it.  In 2014 if the same situation occurred, no one captured it the first time and only one (1) captured it the second time it was transmitted.

Influences Year by Year
2009 and 2010

For both years, the number of sunspots was nil to just a few. Solar activity was very low. In 2010, solar flux increases showed that Cycle 24 had just begun.

When no sunspots are on the Sun, background X-Ray flux is zero (A0.0). So was the case in 2009.  In 2010, the formation of new sunspots created a couple of spikes in the X-Ray flux.

Geomagnetic activity was also very low in 2009. In 2010 there were signs of a few minor disturbances.

The pattern of activity focused on the summer solstice was evident in 2009. In 2010 there was a surge around Independence Day. The trend-line showed that activity peaked at the solstice, normal for 2005-2008.

2011 – The Solar Cycle Gets Active

At the beginning of the measuring period, solar flux was high enough to promote F2 and TEP propagation. As the days passed, it dropped to fairly low levels.

Background X-Ray flux was much higher than 2010. Its value was B1.0 or higher for all but one day. This was probably the best indicator than it would be active in the fall.

Geomagnetic activity was not much different than 2010.

Total PropNET activity was over 50% less than the prior year. It was 27% lower at my QTH. There was little evidence of a peak at the Summer Solstice. Not noted on the graph, it was very inactive from July 9 through the end of the season.

Solar Cycle 24 reached its first of three peaks in November 2011.

Solar/Geomagnetic Activity and PropNET Activity Since 2011:

The best description of Solar Cycle 24 was that it was “anemic”. New regions were always forming, but none lasted a week. Most of the active regions during Cycle 23 would last several rotations of the sun. Although it rose over these years, its movement was like a roller coaster.

Solar Flux 2012-2015

Background X-Ray Flux 2012-2015
The movement of background X-Ray flux was similar to solar flux in that it was rising and declining steadily.  There were really no major/extreme solar flares this solar cycle.

The Geomagnetic A-Index clearly shows that it peaked after Solar Flux was back into decline.  2015 was the most active year.  As mentioned earlier like solar flares, there were fewer large Coronal Mass Ejections (CME) within this solar cycle. Although there were some disturbances, they were generally short-lived.

Recap on the Affects to 10-Meter Spring/Summer Es
The affects on 10-Meter Spring/Summer Es were quite evident.

2011 was the last good year for activity and far less than the previous 2 years.

At the bottom of Cycle 23 and the early stages of 24, 2009 and 2010 were outstanding years.

The cumulative activity of 2011-2015 was not half of what was experienced in 2009-2011. The hour to hour pattern did remain the same, a dual peaked diurnal (mid-morning & late afternoon).

The last 4 years have been very poor and in total just equaled 2011.

When the solar cycle (solar activity) was its lowest, Es peak at the Summer Solstice.

Once solar activity increased, the day to day pattern reversed.
A note: F2 High frequency maximum usable frequency (MUF) actually declines slightly as the Summer Solstice approaches.

Measured PropNET 10-Meter Captures per Hour

These charts really show how bad things became.
In 2010, there were ninety (90) 10-Meter PropNET catches per hour. In 2014 there were barely five (5) catches per hour. The trend-line decline between these years was as perfect a polynomial mathematical equation you can compute (exact equals 1).

These hourly charts show the decline across the day. Each hour of the day was affected equally. The increase between 2009 and 2010 is due to Non-PropNET catches from a change of frequency.

These are twilight hours in N. America. At these times there is little Non-PropNET activity.

At this time the sun has risen in the eastern half of N. America. 

Whether we had great conditions or bad ones, this is the most active and intense hour of the day. The morning sun is visible across N. America.

At this time it is solar noon the center of N. America.

It is now afternoon across N. America.

At this time the sun is beginning to set in the east parts of N. America.

At this time the sun is beginning to set in the western parts of N. America.

By this time the Sun has set across most of N. America.


Everything that has been charted clearly indicated that the rise in solar and geomagnetic activity in the Solar Cycle will kill 10-Meter Spring/Summer Es. I was surprised how truly bad it was. I hope that many of you were on when PropNET fired up in 2004, because we got to experience some phenomenal times through 2010.
What caused it to be as bad as it was?
It is just a theory, but I think the fact that this solar cycle was “anemic” might have been the culprit. 
MUF during the late Spring and early Summer was no higher than 18 MHz.  Had solar flux been much higher, we probably would have had better interaction between the “F” and “E” layers of the ionosphere. In other solar cycles we have seen a number of HF and VHF events be sparked by solar disturbances. None lasted long enough to stir up the ionosphere this cycle. Example, there were no mid/lower-latitude Aurora, nor VHF FAI (Field-Aligned-Irregularities) this solar cycle. To my knowledge, only one F2 opening on 6 Meters occurred (November 2011).

Future Predictions

The dashed line is a 27 day moving average, the rotation of the Sun.

Notice the peaks of geomagnetic disturbances declined throughout the year.

Good news!  The Sun is steadily getting quieter.  It gets a little active now and then, but overall is heading in the right direction. We will probably be at the same point in this cycle as we were in 2005. It was a respectable Es year followed by two outstanding ones (2006 & 2007).

Dust off your old 10-Meter and even your 6 and 2-Meter rigs. Get ready for some future fun.


This will be my final post here on the PropNET Studies Blog. If and when I get the itch to share new observations or discoveries on other reporting systems, you will find them on my personal propagation studies blog;

Thank you PropNET for 10 years of fun and providing me the platform to conduct these studies. It was the right system at the right time. It was a pleasure to have spent the countless days and hours mining, organizing and plotting the data. Presenting it other Hams was pure enjoyment since I did not have to give a test or a pop quiz after it was done.

I have gone full circle, a solar cycle. Now that I am retired, it is time to fully enjoy other aspects of this hobby.

Happy DXing and 73
Art Jackson KA5DWI/7