[BC] FCC question

[Cowboy]

On Friday 19 February 2010 11:59 am, Jeff Glass wrote:
>  Anyone here on the list have a computer program or some other way to 
>  calculate distance to a particular AM contour, given the desired contour, ground 
>  conductivity, and RMS of the antenna? (Assume an Omni antenna).

 Typically, fields are resolved to 1 kilometer.

 Once you know the field at 1 kilometer, you can go to the conductivity
 graph and get the attenuated field at any distance, for any power level.
 Omni or DA won't matter.

 Since those conductivity graphs were empirically determined back
 in the 30's or there-a-bouts, doing it mathematically can get sticky.

 There will be anomalies in any pattern, so this does not necessarily
 mean that it'll agree 100% with a FIM.

 Even with MoM modeling ( to determine pattern shapes and theoretical
 fields absent local distortions ) nothing beats a measured proof done
 correctly, in an environment absent local distortions.
 ( re-rad from structures not included in the model )

-- 
Cowboy