Sunday, March 28, 2010
The first and second charts show hourly captures in directional halves; North-to-South, and East-to-West. The dual-peak diurnal is evident it both opposite directions, but tends to be better defined for northern and eastern paths.
The third hourly chart are the individual 16 weeks of the Spring/Summer Es season. The diurnal pattern is evident each week of the season. The 6th week (5/30 - 6/5) which is the most active, clearly shows a morning active period. The 2nd most active 8th week (6/13-19), clearly shows the dual morning and late afternoon peak.
Please email me: ka5dwi at sbcglobal.net
if you have any comments or questions.
73's Art KA5DWI
Sunday, March 21, 2010
This will be my last post until next weekend. I have to go back to work (Spring Break). To recap, I have posted my 5 years of results by day of the season (4/25 to 8/14) and have also posted annual charts of Es Layer critical frequency to show the base cause for Es propagation.
I will now begin to post charts that show the characteristics of Es.
The first ones are the number of captures by local hour for the five years (2005-2009). The hourly order is displayed as sunrise to sunrise. During the season the sun rises during the 6 AM hour, is at solar noon at about 1:20 PM (13:20) and sets during the 8 PM (20:00) local hour. My local hour is Central Daylight Savings time.
The sunrise to sunrise display was selected to clearly show the Es are diurnal. Diurnal means the pattern is daytime active. For 10 Meter Es (I truly believe all frequencies), the most active period is in the morning hours from mid-morning till noon. There is a second peak around late afternoon but in three of the five years the mornings clearly show the most activity. Most believe that Es are evening active, but it is probably due to the number of Hams active later in the day.
One displays each of the five years and the overall average. The plots are based on a 3 hour average. Example, 6 AM is an average of 5, 6 and 7 AM. The second one is the actual number of captures for 5 years.
Again I will be unavailable most of the week. I will answer questions next weekend.
Thursday, March 18, 2010
For years, many believe that Es are influenced by a number of factors.
1. Solar Conditions
3. Moon phases
4. Jet Stream
5. Electrical activity (Thunderstorms)
Yes there are probable influences, but it is not the root cause for Es.
The root cause for Es are the tidal conditions of the Es layer in the ionosphere.
The charts are from HAARP (sorry, no mind altering is done there). These are foEp; the maximum frequency of the E layer.
In late April, the maximum frequency rises and compresses (High to Low). The maximum occurs at the Summer Solstice and returns to April values in late August. By the way, in the winter it does the opposite.
It does it every year with little change each year.
Later & 73's
Wednesday, March 17, 2010
Here is where I discovered that I really needed to extend my data collection by at least 2 weeks. 8 weeks prior to the summer solstice is the beginning of the Es season. It really doesn't end until 10 weeks after it. Usually I did see the first inactive day around August 15. I do take care of the 2 additional weeks in the probability numbers to be shown later on.
In the first years activity was high early in the season. The final 3 years saw more of the opposite, activity high in the latter half. I was very surprised that the weekly figures were less smooth. There was no doubt that there was an outside influence.
Again, more to come.
Tuesday, March 16, 2010
The following chart is the source data for the study I have been working on.
I am keeping my fingers crossed that it will be published as part of the 2010 Central States VHF Conference proceedings.
It is composed of 65,014 PropNET captures and identified partials from April 20 to August 15 2005 to 2009. The data is only PropNET participants captured here at my QTH in North Central Texas.
There are about 60 other charts of the phenomena that I have done for the study, parts of it I will post and explain in the coming weeks here on the blog.
Stay tuned.... more to come
Art Jackson KA5DWI