The final analysis performed using probabilities was to compare the hour-to-hour trends of each week in the Spring/Summer Es season. With the volume and sampling, we should be able to identify where changes may occur from week to week of the season. Also, if the data accumulated was reliable, did it provide consistent and reasonable results?
Three Week Periods:
The following chart displays probabilities of working Es in 3-week segments from the beginning to the end of the season. The chart clearly details that the 6 weeks prior to and then after the Summer Solstice (12 weeks total) are the best periods for Es. The one fact that is evident is that during this 12 week period there is not much difference between them.
Weeks 1 – 4:
Week 1 (4/25-5/1) starts the Es season with some limited activity in the daytime hours. In Week 2 the best opportunity is in the late afternoon. Probabilities average less than 9% for Week 1 that on any hour a 10-Meter Es PropNET capture can occur. Probabilities almost double (over 16%) Week 2 and will favors afternoon times.
Probabilities more than double between the 2nd and 3rd weeks. Activity this 3rd week of the season clearly favors morning Es activity and typically forms a dual-diurnal pattern to be seen for other active weeks. Due to increased activity the final year of the study, the 4th week increased due to steady opportunities during the afternoon hours. Most of these weekly periods showed higher probabilities in the latter years of the study.
Weeks 5 – 8:
These are the weeks approaching the Summer Solstice. Probabilities in Week 5 increase over 8% to over 50% overall. Week 6 has the third highest probability of the Es season (near 58%) and had the highest of the season prior to the final year. The local 10 AM through 1 PM hours have probabilities of a 10-Meter PropNET capture at or above 90%.
Despite the high activity of the 6th week of the season, the 7th week (6/06) drops off over 7%. The drop off occurs during the morning hours. Week 8 returns to the level of Week 6 and has a rise in twilight activity that shows that the Summer Solstice is the peak of the season. Once again, this did not show until the latter years of the study.
Weeks 9 – 12:
Week 9 (6/20) is the week than contains the Summer Solstice. It changes little from Week 8 as there is a less than 1% increase, but the week is more morning active. There is a significant (more than 10%) decrease in Week 10, followed by a healthy resurgence of 12.6% in Week 11. This is the week that contains the Independence Day (July 4th) holiday and traditionally is known to be a very active week for Es propagation. Week 12 is unusual in that it declines in afternoon and evening activity. Most week to week declines have occurred during the morning hours.
Weeks 13 – 18:
The usual “morning decline” pattern occurs again in Week 13. Week 14 has a surge in activity is as Week 10. The sudden increase is noticeable from year to year. July 29 is usually active and is one of the more active days each season. The final two weeks, Week 15 and Week 16 also have steady afternoon declines in activity. The declines are slight. Week 16 overall probability is only slightly above 5% lower than Week 13. It was a poor assumption on my part that the Es season ends by August 15. Usually the first activity-free day does occur near or around the date, but Es activity continues until the first of September. By continuing the data collection for two additional weeks, it is noted that activity returns to levels experienced at the beginning of the season and once again becomes truly sporadic in nature.
Conclusions About 10-Meter Es Propagation:
In my 35 years of monitoring and working these phenomena, I have heard many theories as to their generation and occurrence. Some of these theories that have been proclaimed, I personally do not consider them to have any major effect of the trends shown in these charts. I strongly believe that too many have tried to figure out the wonders of Es and ignore the consistencies that it is displaying. Placing its generation of single natural and physical situations and phenomena is difficult to prove. I hoped that this 5-Year Propagation study would dispel many single-cause theories and provide mathematical, scientific, and logical answers based on consistent patterns and trends.
If Es were caused by a specific ionosphere or atmospheric events, consistency and patterns in the charts from the study would not occur. Much is still left to science to find the real cause and a mathematical approach using practical data gathering practices can show the reliability and consistency of the phenomena and dispel these types of theories.
In addition, this study was not compiled in order to predict when your specific 2, 6 or 10 Meter QTH could connect to another specific QTH. It was strictly compiled to identify the best dates, times and possible directions to work them.
Next: The Final Level of Analysis
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