Topband: GAP Vertical Question

[Paul Christensen]

> Right, typically a couple hundred ohms.  Modeling the base Z of a thick 
> broadcast tower is very difficult with MoM software.  Changes in thickness 
> can result in large base Z changes.

Just to be clear, since the discussion drifted to half-wave radiators, my 
comment above was specific to the modeling of thick v. thin half-wave 
radiators, including the 180-195 degree radiators of some well-known 50KW AM 
stations.  The results when modeling the base Z of approx. 1/4-wave 
radiators is less affected by thickness, probably due to a lower base Z to 
start with.

Paul, W9AC