Conclusions About 10-Meter Es Propagation:
In my 38 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 7-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. 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.
The Final Level of Analysis:
Now that 7 years of data was collected and PropNET participation each year was consistent and the data displayed definitive trends, there were still existed some holes day to day. Although I averaged days in my plots, most daily charts displayed peaks and valleys. It stirred up my curiosity and I decided to investigate it on a micro level. I found historically active and inactive days.
Seven years of participation has produced excellent probability data supported by capture numbers. It was proven that the higher the probability of Es, the number of captures during the occurrence is also higher. In order to define the best days of the season, I established the four levels to rank.
These were:
- Probability (active hours of the day)
- Intensity (high activity rates during an opening)
- Activity (day’s total activity)
- Overall ranking (compared to other days of the season)
Also, these factors are weight to the overall merit of the day. Individual days and specific conditions within them are noted for the best 60 and 20 days of the season. If day is in bold blue, it is one of the best 60 days. If red, then it is one of the best 20.
This is applied to a calendar from April 25 until August 14. The best days are focused on the Summer solstice, but it is interesting to see peak and valleys at unexpected days.
1st Quartile Spring/Summer Es Season (April 25 - May 22):
The following table displays the first 4 weeks of the Spring/Summer Es season. The incline of activity is gradual. The first intense day is May 11. This period alerted me that there was an outside influence to Es propagation. May 22 is the only Top 20 day during the period.
April 25
|
April 26
|
April 27
|
April 28
|
April 29
|
April 30
|
May 1
|
May 2
|
May 3
|
May 4
|
May 5
|
May 6
|
May 7
|
May 8
|
May 9
|
May 10
|
May 11
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 12
|
May 13
|
May 14
|
May 15
|
May 16
|
May 17
|
May 18
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 19
|
May 20
|
May 21
|
May 22
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
2nd Quartile Spring/Summer Es Season (May 23- June 19):
This table confirms that Es are seasonable and its best conditions occur around the Summer Solstice. Of the best 20 days, 9 of them occur during this period. Only May 25 and June 7 fail to have any Top 20 or Top 60 results.
Only 2 days fail to make the rankings. The period from June 2 through June 19 is the best time of the season and one should focus of all their DXing activities around this time.
May 23
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 24
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 25
|
May 26
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 27
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
May 28
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
May 29
TOP 60
INTENSITY
|
May 30
TOP 60
ACTIVITY
PROBABILITY
|
May 31
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 1
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 2
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
June 3
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
June 4
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
June 5
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
June 6
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 7
|
June 8
TOP 60
PROBABILITY
|
June 9
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 10
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 11
TOP 60
ACTIVITY
TOP 20
PROBABILITY
|
June 12
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
June 13
TOP 60
INTENSITY
TOP20
ACTIVITY
PROBABILITY
|
June 14
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 15
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 16
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
June 17
TOP 60
INTENSITY
ACTIVITY
TOP 20
PROBABILITY
|
June 18
TOP 20
ACTIVITY
PROBABILITY
TOP 60
INTENSITY
|
June 19
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
3rd Quartile Spring/Summer Es Season (June 20 – July 20):
As in the prior quartile, 8 of the 20 top activity days occur also in this period. Every day is ranked. The first and fourth best activity days of each Spring/Summer Es season are July 8 and June 30.
June 20
TOP 60
PROBABILITY
|
June 21
TOP 60
INTENSITY
ACTIVITY
TOP 20
PROBABILITY
|
June 22
TOP 60
INTENSITY
ACTIVITY
TOP 20
PROBABILITY
|
June 23
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
June 24
TOP 60
INTENSITY
ACTIVITY
TOP 20
PROBABILITY
|
June 25
TOP 20
ACTIVITY
PROBABILITY
TOP 60
INTENSITY
|
June 26
TOP 20
ACTIVITY
PROBABILITY
TOP 60
INTENSITY
|
June 27
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
June 28
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
June 29
TOP 60
ACTIVITY
PROBABILITY
TOP 20
INTENSITY
|
June 30
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
July 1
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
July 2
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
July 3
TOP 60
ACTIVITY
PROBABILITY
TOP 20
INTENSITY
|
July 4
TOP 60
ACTIVITY
TOP 20
PROBABILITY
|
July 5
TOP 60
ACTIVITY
PROBABILITY
TOP 20
INTENSITY
|
July 6
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
July 7
TOP 20
ACTIVITY
PROBABILITY
TOP 60
INTENSITY
|
July 8
TOP 20
INTENSITY
ACTIVITY
PROBABILITY
|
July 9
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
July 10
TOP 60
PROBABILITY
|
July 11
TOP 60
ACTIVITY
PROBABILITY
|
July 12
TOP 60
INTENSITY
ACTIVITY
|
July 13
TOP 60
ACTIVITY
PROBABILITY
TOP 20
INTENSITY
|
July 14
TOP 60
INTENSITY
ACTIVITY
|
July 15
TOP 60
ACTIVITY
PROBABILITY
|
July 16
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
July 17
TOP 60
INTENSITY
ACTIVITY
|
4th Quartile Spring/Summer Es Season (July 21 – August 15):
During this period, Es begin a general decline. Still, Es activity remains active well into August. Excellent hourly openings occur on July 28 and 29. July 29 has had a history of being one of the top 10 days of the season. Daily lulls become more common place, but no clear end of the season appears until after August 15. The Es season quietly ends 2 weeks after that date.
July 18
TOP 60
ACTIVITY
PROBABILITY
|
July 19
TOP 60
PROBABILITY
|
July 20
TOP 60
PROBABILITY
|
July 21
|
July 22
|
July 23
|
July 24
TOP 60
PROBABILITY
|
July 25
TOP 60
PROBABILITY
|
July 26
TOP 60
INTENSITY
ACTIVITY
|
July 27
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
July 28
TOP 60
ACTIVITY
TOP 20
INTENSITY
|
July 29
TOP 20
INTENSITY
ACTIVITY
TOP 60
PROBABILITY
|
July 30
|
July 31
|
August 1
|
August 2
TOP 60
INTENSITY
|
August 3
|
August 4
TOP 60
INTENSITY
ACTIVITY
PROBABILITY
|
August 5
|
August 6
|
August 7
|
August 8
|
August 9
|
August 10
TOP 60
INTENSITY
|
August 11
|
August 12
TOP 60
INTENSITY
|
August 13
|
August 14
|
Questions and Answers:
“Is Es propagation truly a seasonal occurrence?”
The answer derived from this study is definitely yes. The season begins within days of April 25 and progressively increases up to May 6, at which time it is in full swing and remains totally active until at least August 15. There is still a good chance that activity continues till the end of August. From the study, the season begins 8 weeks prior to the Summer Solstice and ends around 10 weeks after it.
“Since it has been determined to be seasonal, is activity evenly distributed around the Summer Solstice?”
After three years, I thought it was not. After 5 years of the study the trend-lines show it is. The best part of the Es season is concentrated in the first half (8 weeks long) in a 4-week segment and one should make as much effort as one can during that period. Es are great from the 3rd week through the 6th week (May 9 – June 5). Some years it might calm down slightly for two weeks around the solstice, but it in no way does it mean that the season is over. It is still very active during that lull. Once we arrive at Independence Day (July 4th), the season picks up again and it is not until around August 1 that a real decline is noticed. The season does not actually end until sometimes between August 15 and September 1. Statistically and graphically it has a slight right-skewed distribution of opportunities, still the median points of captures and opportunities rested near the Summer Solstice.
“It appears that one works most of their QSOs during the afternoon and evening hours. Is this the best time to work Es?”
No it is not. It appears this way only because most Hams are active late in the afternoon and evenings. The absolute best hours are from after sunrise till the actual Solar Noon hour. On weekends and days off from work, make every effort during the season to work Es during these hours. The late afternoon hours are also very good. The distances covered (DX) are also better, but opportunities decline once the sun has set. Es are mostly diurnal (daytime phenomena). Es do occur in the late evening and early morning hours. When they do, it is a very special event. Enjoy it and make use of the opening.
“Do Es favor specific directions at certain times?”
Yes it does, and it has to do with the location of the sun. It appears that you follow the sun in order to apply where it is best. As the sun rises, the best conditions tend to be towards the North and East. Gradually, as the sun is high over the horizon, southern paths improve. Once the sun has moved beyond Solar Noon, western paths become better than eastern ones. Therefore, the tendency is that openings appear in the east and north first and then will develop towards the south and the west later on. The process starts over again in the afternoon as was displayed in the dual peak diurnal. Once the sun is setting, northern and western paths will decline in activity at a slower rate while southerly and easterly ones may drop off quickly.
“Can one predict when it is the best time to work real DX locations on Es?”
Yes…..
1. If the DX location is primarily east of you… Concentrate your efforts towards the DX station as your Sun has risen and then once again as the Sun’s Grey Line approaches the eastern DX locale.
2. If the DX location is west of you …Concentrate your efforts towards the western DX station as their Sun rises and then once again as your Sun sets.
3. For Northern and Southern DX paths ….Concentrate your efforts along the suns Grey Line as it leaves or approaches both locations.
This approach appears to produce better results.
“Do severe weather systems and the Jet Stream have any affects on Es propagation?”
Predominately it is small to absolutely none. An opening due to thunderstorms is very remote.
A weather system may influence Es propagation between two specific points (experienced here a few times), but I found it difficult to correlate its influence over the entire creation of the phenomena. This study covered over 800 days of the Spring and Summer season, over a 7-year period. Of the entire seasonal total, I could only determine that an extremely small percentage of PropNET captures had anything to do with weather systems. In these 7 years, 4 of them were drought years with very little jet stream wind flow and little electrically active weather to speak of. If weather was the primary influence, the hourly charts would have represented trends indicative to weather affects. They clearly failed to do so. For 5 of the 7 years of the study, the morning daylight period was clearly the best times for Es propagation. Severe weather is a late afternoon, early evening occurrence. Captures in all 7 years never displayed the highest activity in the afternoon and only equaled in two. In addition, Es would have also occurred at high levels in many other times of the season with varying levels. The study does not show that as is shown by its clear absence of captures in early April and much less than intense when it was open.
“Are there any other possible external influences that might affect Es?”
Probably meteors increase the probability of Es.
These were the actual daily captures of record for the 7 years of the study.
This is the potential meteor shower rates per hour for each day during the Es season.
Source: DL5BAC’s The Meteor Scatter Predictor Program (TMSP)
It was not perfect for all peaks of meteor activity, but many of the spikes in captures during the 7 years coincide along them. Meteor influence was brought to my attention at the end of the season when there was an increase in Es activity on July 29-30, August 2 and August 13-14 when one would think that activity should have been very limited.
“What might cause the overall lull in activity and probability during the weeks around the Summer Solstice?”
The high angle of the Sun during this period might have an affect on Mid-Latitude Es. The Nighttime probabilities actually peak during the solstice, therefore it points towards the peak during this period. Maybe the heat radiated off the earth, in addition to the high sun angle deters ionization of the Es layer to some extent. The final three years were minimum solar activity years. The lull was much less pronounced during this time.
“Is the term “Sporadic” a proper identification of the Es propagation phenomena?”
The description of the Physics for Es is correct, but as for a phenomenon it is absolutely not.
At the 2011 Central States VHF Society convention, James Kennedy-W6MIO/KH6 described the “E” layer and patches that reflect signals as being sporadic. But during the Spring and Summer those patches are visible as you look around and above the horizon.
The Houghton Mifflin Dictionary defines “Sporadic” as:
- Occurring at irregular intervals; having no pattern or order in time.
- Appearing singly or at widely scattered localities, as a plant or disease.
- Isolated; unique: a sporadic example
The 7 years of the study and the resulting charts show that Es display no such conditions of being Sporadic.
Therefore, we should use the opposite term, “Periodic”.
“Periodic” is defined as:
- Having or marked by repeated cycles.
- Happening or appearing at regular intervals.
- Recurring or reappearing from time to time; intermittent.
Periodic appears to be a much better adjective used to describe Spring/Summer Es propagation. As for Es being called “sporadic”, I think it still gives them a very bad rap.
Glossary
Afternoon Active - Most occur in the afternoon daylight hours.
Morning Active – Most occur in the morning daylight hours.
Averaging Data – It was used to smooth out peaks and lulls between actual days and better concentrate data gathered for hourly statistics. Solar Indices are displayed in running averages. It did not change the actual totals if the data displayed was accumulated.
Diurnal - Webster’s Dictionary defines this term as:
Recurring every day, occurring in the daytime, or opening during the day and closing at night.
Dual Peaked Diurnal – Two peaks of activity occur in the daylight hours.
Es Propagation – The bending of radio waves in the ionosphere at frequencies from approximately 10 – 230 MHz (25-50 MHz most common) by what is known as the E-Layer of the ionosphere (50-80 miles). Due to its lack of its predictability, it is often referred to as “Sporadic Es”. It is also known as “Short-Skip” because it propagates at shorter distances than normal F2 layer propagation at high frequencies.
Median – American Heritage Dictionary defines this term as:
Relating to, located in, or extending towards the middle
Probability Analysis – Based on the premise that one event occurs for a given time period. In the study, a single capture in an hour would have the same value at 100.
Right Skewed – Statistics term used to describe charted data. If most of the data volume is located to the left of center, it is considered right-skewed.
Right Tailed - Statistics term used to describe charted data. If the chartered data declines at a slower rate and time than it first rises, it is considered right tailed.
SE-Prop – DOS and Windows program developed by Jim Roop - K9SE that displays probable E-Cloud location and MUF between two stations.
Summer Solstice – It is the day that the Sun is directly over the Tropic of Cancer (approximately 23.5° North latitude). It is the highest elevation that the Sun will appear in the Northern Hemisphere. It marks the Winter Solstice in the Southern Hemisphere. When the same condition occurs in the Southern Hemisphere over the Tropic of Capricorn (approximately 23.5° South latitude), it is the Summer Solstice for the southern hemisphere and the Winter Solstice for the northern hemisphere.
Solar Noon Hour – The actual time (hour measured) that the Sun is due south. During Central Daylight Time it occurs at 13:18 or 1:18 PM at grid square EM12ju.
Digisonde – A device that measures the values of returned high frequency radio signals transmitted and received in order to determine ionospheric layer altitudes. The University of Massachusetts Lowell Millstone Hill Digisonde
W6ELProp – Windows computer program developed by Sheldon C. Shallon, W6EL used for predicting ionospheric (sky-wave) propagation between any two locations on the earth on frequencies between 3 and 30 MHz. Earlier DOS versions were known as MINIPROP and MINIPROP Plus.
A Never-Ending Thank You to the PropNET Organization……..
Rank Call Grid Square Distance Captures
1 WD4RBX EM84NN 1338 11724
2 WB8ILI EN82OQ 1669 9234
3 K8VGL EM69UT 1245 7322
4 K4RKM EM85VF 1406 6995
5 W4JKL EM84AK 1238 5026
6 AD4RX EL88OD 1475 4443
7 KC9MEG EN52TI 1310 3106
8 KD5LWU DM57RI 1145 2955
9 K4EPS EL86UW 1579 2887
9 K4EPS EL86UW 1579 2887
10 N7YG DM42NF 1282 2828
11 K1MEA DM33TP 1412 1821
12 KI4EIZ EM63KN 941 1770
13 NZ9Z EN64BD 1492 1716
14 NM4V FM06NR 1748 1655
15 N4LR EM73QN 1172 1626
16 KF9KV EN52ET 1291 1249
17 N4PSN EM84KP 1319 1245
18 KC0EFC EM28OX 715 1004
19 KI0GU EN35HF 1413 974
20 KF6XA DM13JO 1859 936
21 W2EV FN03XD 2026 932
20 KF6XA DM13JO 1859 936
21 W2EV FN03XD 2026 932
22 WN4AMO EL98CW 1532 861
23 W6CGH DM13BR 1920 735
24 N8QLT EN82HL 1617 707
25 N0OBG EM48RO 877 705
26 KC6QJO DM05KH 2035 701
27 W3GYK EM85VF 1409 620
28 W3NRG DM12JQ 1867 568
29 WN3C FM19QC 1975 539
30 AB0TJ DN60CN 1277 514
31 WB8SKP EM56WR 933 509
32 KP3FT FK68QA 3467 502
73s Art Jackson KA5DWI
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