Frequently Common Midpoint Squares and 144MHz single hop Es propagation

(2012-09-15) PE1ITR


I hear regularly the story that there are areas where more Es reflection point exists then other areas The question is whether this is true? Has the earth's surface influence to the place where the reflection areas 110 km above the earth are located. Or has it more to do with the distribution of observers and the active radio amateurs created these hotspots only by theire location? This webpage is a little research on this subject.

The search for frequently common squares

First I searches my database for 144MHz Es spots and counted the maidenhead midpoint squares with a 6 digit locator resolution. The midpoint square is the middle of the squares of two stations. Only single hop distances where counted.
The images shows the distribution of the midpoint squares from 2001 to the year 2012. The blue spots are at least for one count in the query. The red spots more than 5 count. The orange spots more than 10 counts and the yellow spots more than 15 counts. From the image it is clear that the midpoints can be everywhere.

The counts of the yellow spots are from 15 to 24 counts. This seems extremly high. Are these yellow dots the hotspots we are writing about?
I zoomed into each spot.

The most frequently common squares

The table shows the yellow midpoint spots.
Maidenhead SquareLinkRemarkssurrounding count
IN62EVimageSpot over land. count:15. 8 events between EI5FK and CN8LI in 2006,2007, 2008 and 2009.-
IN63JRimageSpot over water. count:15. 13 events between G4LOH and CT1HZE in 2006, 2007, 2008, 2009, 2010, 2011 and 2012.-
JM09UWimageSpot over water. count:15. 12 events between IW0AJJ and CT1HZE in 2007, 2008, 2009, 2010, 2011 and 2012.-
KN12SXimageSpot over land. count:15. 10 events between IC8FAX and UT5JCW in 2003, 2007, 2008 and 2009. Note FAI.-
KO14XQimageSpot over land. count:15. 8 events between RA3WDK, UA3WM and OZ5AGJ, OZ1SKY, OZ8ZS in 2006, 2010 and 2011.-
JN00QAimageSpot over water. count:16. 11 events between CT1HZE and IK0SMG, IK0OKY in 2007, 2008, 2009 and 2011.-
JN00RCimageSpot over water. count:16. 14 events between CT1HZE and IW0BYL, IK0BZY, IK0FTA, IK0VKL, I0YLI and I0DLP in 2006, 2007, 2009, 2010 and 2011.-
KN57PCimageSpot over land. count:16. 5 events between RX3QFM and LZ1AG, LZ1ZP in 2004, 2005, 2007, 2009 and 2010.-
IN64JFimageSpot over water. count:17. 10 events between EI5FK and EA7TN, EA7TL in 2006, 2007, 2009 and 2010.-
JN26DIimageSpot over land. count:17. 13 events between G4LOH and IK0BZY, PA3C and EA6VQ in 2004, 2006, 2008, 201, 2011 and 2012.-
JN63BGimageSpot over land.-
KN38FCimageSpot over land. count:18. 7 events between OK1TEH and RZ6BU in 2006 to 2012-
HM93MMimageSpot over -
IM18BIimageSpot over water. count:29. line:1. 22 events between CT1HZE and CU3EQ in 2006 to 2011.AJ:0,BJ:0,CJ:0,AI:0,CI:1,AH:0,BH:0,CH:0

The table shows thera are only a few amateurs involved. It looks like these hotspots have a heigh count because there are two active stations at each end. To be certain we count also the surounding squares as a midpoint square.

Frequently Common Squares versus Year