function [gewdbi,vrdb] = rp3d(ant,freq,grid,elev)
% [gewdbi,vrdb] = rp3d(ant,freq,grid,elev)
% Radiation diagrams: horizontal, vertical and 3D.
%
% ant  :  antenna description.  There are three options:
%         MATLAB expression  :   description in ADL
%         sring :   file with description in NEC-syntax
%         {string; p} : string = file with description in AAL-syntax; 
%                       p = antenna parameters
%
% freq :  frequency in MHz.
%
% grid :  grid spacing to be used in the 3D-diagram in degrees
%         (default = 5)
%
% elev :  elevation angle in degrees for the horizontal diagram (default = 0).
%         If ground parameters are used, there is zero radiation at elevation 0.
%         In the case of HF-antennas  elev = 15  should be used.
%
% gewdbi: gain over isotropic radiator (dB) 
