Topband: More anecdotal "stories" to cause one to stop and....

Richard Fry rfry at
Fri Sep 13 07:43:47 EDT 2013

Jack WS3N wrote:
>Then it would seem that what you call the surface wave must be the 
>remaining part of the complete solution, and so it must decay exponentially 
>in the vertical direction. ... a decaying solution can't be projected in a 
>straight line and assumed to reach the ionosphere.

The radiated field of a vertical monopole present on the surface of lossy 
earth decays at greater than a 1/R rate.  But, for example, the field shown 
at a horizontal distance of 0.1 km in my surface wave plot for an elevation 
angle of 5 degrees is not located on the surface of the earth.  It is about 
9 meters above it, and in fact, is a space wave.

Space waves DO decay at a 1/R (non-exponential) rate until they reach the 

Here is a link to a clip from Radio Engineers' Handbook by F.E. Terman (1st 
Edition), showing that the greatest single-hop range for radiation from a 
1/4-wave monopole leaves the monopole at elevation angles below 5 degrees.

The reduction in skywave field intensity seen in this clip beyond 150 miles 
downrange is due to the 1/R losses of those longer paths. 

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