Topband: EIRP Measurement

[Paul Christensen]

> Fortunately, it is not true with short ground mounted monopole
> antennas.  In order for the skywave to exceed the groundwave, the
> monopole needs to be longer than half wave (somewhere in the area
> exceeding 0.64 wave).

I believe Rich Fry pointed this out a couple months ago.  The effect can be 
seen when using the surface wave modeling tool in 4Nec2.  At first, it 
surprised me since nearly all base-fed, vertical radiator elevation profile 
charts show little field strength at low elevations (1 or 2 degrees), even 
when fed over a substantial radial field.  Typical vertical profile charts 
show high surface wave field strength only over salt water.  The same is 
shown using NEC modeling programs unless a surface wave tool is used.

Paul, W9AC