Topband: Ground Conductivity

[Augie "Gus" Hansen]

On 3/25/2020 11:57 AM, Jim Brown wrote:
> ...
> I don't know if it's still required today, but when I worked in 
> broadcasting, each station using a directional antenna was required to 
> make periodic field strength measurements in their nulls to proof 
> their pattern.

Back in the 1960s when I was chief engineer at an AM station along the 
Rhode Island coast (Westerly) we had to pass periodic checks, not for 
nulls - it was a single stick - but for verifying the required signal 
strength over the licensed coverage area. The issue was the radial 
system that was in swampy land on the bank of a river where it dumped 
into the Atlantic Ocean. The salinity varied widely with river flow, 
tides, and seasons.

Gus Hansen
KB0YH