Takeoff and landing angles For European DX

Speculations :  Maybe, one of the reasons I have problems with Europe here at the home QTH in Kalau’au (aka Aiea) is  the terrain. Using the incomparable Google Earth and the “Show Elevation Profile: feature of the Edit menu, it is possible to calculate the slope between points.  I made a couple of transects using the “line” feature, then “show elevation profile” to get readings of the grade (in %).   A Google search readily provides conversions of grade to degrees.  

kh6dk N Elev Profile

Going NNE from my QTH, the slope is as much as 32% or about 18°.    This means that inbound low angle radiation below 18°  encounter the Koolau mountain mass.  Likewise, low angle transmissions to the North are subject to absorption by the ground.   The greater the distance south of the mountain, the lesser the angle so locations on nearer the coast have a better shot at Europe than  a location on the hill where the grade is maximized.

oahu_terraine The QTH is around the red mark …  maybe a little up…  

On Oahu, this also explains the superiority of North facing coasts for Northern Hemispheric DX.  On the north shore beaches, there is no mountain to block low elevation signals, and where you can get benefit of the superior and perfect salt water ground plane of the Pacific Ocean.

~ by marksun on August 31, 2014.

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