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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