Topband: Elevated Radials on Grounded Tower?
Richard Fry
rfry at adams.net
Thu Sep 20 20:00:34 EDT 2012
Earlier...
> I hope we all caution people models are models and can vary from life, and
> that empirical reports should be taken with a grain of salt.
____________
Good advice, but probably anecdotal reports need even more grains of salt.
Broadcast engineering consultants now use MoM (NEC) models to develop and
file FCC data for grant of a construction permit for the directional
radiation pattern(s) required for a given AM broadcast station application.
The FCC accepts such filings, pending verification of the pattern after
installation (which also is required when MoM is not used).
The link below shows the data measured by a broadcast consulting engineering
firm for the stated conditions using a calibrated field intensity meter,
with the groundwave field intensity data calculated by NEC for those same
conditions.
Correlation of the NEC data with the empirical data is very good.
http://i62.photobucket.com/albums/h85/rfry-100/Measured_vs_NEC2D_Fields2.jpg
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