How Do I Correctly Plot an Electric Field Around a Base Station Using MATLAB?

[jadelsky]

Homework Statement

I need to plot an electric field in some range around base station, for example in range of 200m.

EIRP=57,5dBm
G=1 for the first example
N=4

Homework Equations

E=[2*sqrt(30*N*P*G)]/r
P=10exp[(EIRP-30)/10]
EIRP=57,5dBm
G=1 for the first example
N=4

The Attempt at a Solution

[X,Y] = meshgrid(-200:.50:200,-200:.50:200);
E=520./sqrt(X.^2+Y.^2);
contour(X,Y,E);

so when i calculate the numerator it's around 520 so i just placed it directly, and in the denominator part i placed sqrt(X.^2+Y.^2) so it's the result for any distance from the station in this range from 0 to 200...the result i get is not good, i used contour plot, I'm really not that familiar with plotting in MATLAB so this is the first option i thought will work (maybe there are better options?)...in the attached file i made a snapshot of my result and the result of some other example...my result should look something like that...

I would appreciate any help very much...Thanks!

 

[jadelsky]

and also i should include G (gain) in the equation so it all don't come out symetric but i got no idea how should i do it...