ploting a function handle

can someone help me out please. I'm trying to plot this code but it gives me some errors ı don't know how to solve. It's my first time to use handle function.

close all;
clear variables;
clc;

f =1:0.1:28;
SF=4.0;
d0=1;
c = 3e8;
h_BS = 15;
TRDistance= 20;
h_BS = 15;
TRDistance= 20;
TXPower=30;

lambda = @(f) (c/(f*1e9));
PL_dB = @(f)(20*log(4*pi*d0*f*1e9/c) + 23.1*(1-0.03*((h_BS-35)/35))*log((TRDistance)) + SF*randn);
Pr_dBm =@(f)( TXPower - PL_dB);

figure;
plot(f, Pr_dBm(f));
xlabel('f');
ylabel('Pr_dBm');

Answer 1

[madhan ravi]

 SF=4.0;
 d0=1;
 c = 3e8;
 h_BS = 15;
 TRDistance= 20;
 TXPower=30;
 lambda = @(f) (c/(f*1e9));
 PL_dB = @(f)(20*log(4*pi*d0*f*1e9/c) + 23.1*(1-0.03*((h_BS-35)/35))*log((TRDistance)) + SF*randn);
 Pr_dBm =@(f) TXPower - PL_dB(f);
 figure(1)
 fplot(Pr_dBm, [1,28])
 xlabel('f')
 ylabel('Pr_dBm')

[Ca Mai]

Thank you very much. it works

Answer 2

[Arthur Roué]

You are trying to subtract a variable with a function handle

Pr_dBm =@(f)( TXPower - PL_dB);

You should evaluate the function. This might work

Pr_dBm =@(f)( TXPower - PL_dB(f));

[Ca Mai]

thanks alot. it works