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
_______________________________________________ Topband reflector - [email protected]
