why when i plot the graph for the okumura model it doesnt show line?

%Matlab cache clearing commands
clc;                                                                        %clears command window
clear all;                                                                  %clears workspace variables
close all;                                                                  %closes all external matlab windows
%input starts here
Hte=100;                                                                    %Base Station Height between 30 m and 1000 m 
Hre=10;                                                                     %Mobile Station Antenna Height between 1 m and 10 m 
d =1;                                                                       %distance from base station between 1Km and 100Km 
f=900;                                                                      %Frequency between 150Mhz and 1920Mhz 
Amu = 18;                 %Median attenuation
Kcor =9;                 %Correction factor
 
%SUBURBAN AREA
for i=1:length(f)
    Lfsl = 10*log((((3*10^8)/f(i))^2)/((4*pi)^2)*d^2);                                               % finding free space loss
    Ghte = 20*log(Hte/200);                                                                          % Base station antenna height gain factor
    if(Hre>3)
        Ghre = 20*log(Hre/3);                                                                        % Mobile station antenna height gain factor
    else
        Ghre = 10*log(Hre/3);
    end
    L(i) = Lfsl+Amu(i)-Ghte-Ghre-Kcor(i);                                                          % formula for path loss
end
 
disp(L)                                                                     %prints the Loss Array
% plot of Distance vs Loss (dB) for surburban 
 
figure(1)                                                                   %Enables the figure
plot(f,L);                                                                  %versus plotting command
title('Distance vs Loss (dB) for open area for Okumura Model');            %title of the plot
xlabel('Distance(Km)');                                                    %label for X-axis
ylabel('Propagation Path loss(dB)');                                        %label for Y-axis
grid on;                                                                    %Enables Grid feature in plot
%inputs
%    50
%    5
%    10
%    [200 300 400 500 600 700 800 900 1000 1100]
%    [20.4 20.45 20.5 20.55 20.6 20.65 20.7 20.75 20.8 20.85]
%    [23 24 25 25.5 26 27 27.5 28 28.75 29]

[NORFAZNEZA NAZLINDA MOHD NORDIN]

thank you for answering my question

Answer 1

[Stephan]

f is a scalar here - for this reason you have only one data point. Either use scatter to visualize the point or make f an array of values that you are interested in (this is waht i did here). Also you dont need a loop - your code can be vecotrized:

%Matlab cache clearing commands
clc;                                                                        %clears command window
clear all;                                                                  %clears workspace variables
close all;                                                                  %closes all external matlab windows
%input starts here
Hte=100;                                                                    %Base Station Height between 30 m and 1000 m
Hre=10;                                                                     %Mobile Station Antenna Height between 1 m and 10 m
d =1;                                                                       %distance from base station between 1Km and 100Km
f=200:900; % MADE AN ARRAY FROM f                                                                     %Frequency between 150Mhz and 1920Mhz
Amu = 18;                 %Median attenuation
Kcor =9;                 %Correction factor

%SUBURBAN AREA

Lfsl = 10*log((((3*10^8)./f)).^2)/((4*pi)^2)*d^2;                                               % finding free space loss
Ghte = 20*log(Hte/200);                                                                          % Base station antenna height gain factor
if(Hre>3)
    Ghre = 20*log(Hre/3);                                                                        % Mobile station antenna height gain factor
else
    Ghre = 10*log(Hre/3);
end
L = Lfsl+Amu-Ghte-Ghre-Kcor;                                                          % formula for path loss


disp(L)                                                                     %prints the Loss Array
% plot of Distance vs Loss (dB) for surburban

figure(1)                                                                   %Enables the figure
plot(f,L);                                                                  %versus plotting command
title('Distance vs Loss (dB) for open area for Okumura Model');            %title of the plot
xlabel('Distance(Km)');                                                    %label for X-axis
ylabel('Propagation Path loss(dB)');                                        %label for Y-axis
grid on;                                                                    %Enables Grid feature in plot
%inputs
%    50
%    5
%    10
%    [200 300 400 500 600 700 800 900 1000 1100]
%    [20.4 20.45 20.5 20.55 20.6 20.65 20.7 20.75 20.8 20.85]
%    [23 24 25 25.5 26 27 27.5 28 28.75 29]