# Chapter 13 Wave Propagation¶

## Example 13.1 Page no 628¶

In [2]:
#given
x=(2*(1/2.0))
a=15
d=53.5*10**-6                           #duration for each horizontal line on the reciever
t=1/186000.0                            #time delay between direct and reflected signal

#calculation
g=(t/d)*a                               #ghost width

#result
print"ghost width = ",round(g,2),"in."

ghost width =  1.51 in.


## Example 13.2 Page no 641¶

In [7]:
#given
S=83                        #satellite longitude in degrees
N=90                        #site longitude in degrees
L=35                        #site longitude in degrees

#calculation
import math
b=0.1512                     #constant in equation
A=180+math.atan(math.tan(-7*3.14/180)/math.sin(35*3.14/180))*180/3.14
E=math.atan((math.cos((S-N)*3.14/180)*math.cos(L*3.14/180)-b)/math.sqrt(1-((math.cos(L*3.14/180))**2*(math.cos((S-N)*3.14/180))**2)))*180/3.14

#Result
print"The azimuth is equal to A = ",round(A,0),"degree"
print"the elevation angle  = ",round(E,1),"degree"

The azimuth is equal to A =  168.0 degree
the elevation angle  =  48.7 degree


## Example 13.3 Page no 646¶

In [7]:
#given
import math
x=(32+(44/60.0)+(36/3600.0))                           # N latitude
y=(106+(16/60.0)+(37/3600.0))                          #W longitude
D=42.1642*10**6                                    #distance from the satellite to the center of the earth
a=32.74333*3.14/180.0                             #in degree
B=-7.27694*3.14/180.0                               #in degree

#calculation
q=math.cos(a)*math.cos(B)

d=math.sqrt(D**2+R**2-(2*D*R*q))
c=2.997925*10**5                                    #velocity of light
de=d/c
rd=(2*d)/c

#result
print"N longitude converted into degrees = ",round(x,2)
print"W longitude  coverted into degrees =",round(y,2)
print"distance =  ",round(d/1000,1),"*10**6 meters"
print"delay =",round(de/1000,3),"seconds"
print"roundtrip delay = ",round(rd/1000,3),"seconds"

N longitude converted into degrees =  32.74
W longitude  coverted into degrees = 106.28
distance =   37009.1 *10**6 meters
delay = 0.123 seconds
roundtrip delay =  0.247 seconds


## Example 13.4 Page no 651¶

In [19]:
#given
G=45                                     #antenna gain
nt=25                                    #antenna noise temperature
nt1=70                                   #LNB noise temperature
nt2=2                                    #noise temperature(reciever and passive components)

#calculation
import math
T=nt+nt1+nt2                             #total noise temperature
x=G-10*math.log10(T)                     #figure of merit

#result
print"Sum of all of the noise temperature contributions Ts = ",T,"k"
print"The figure of merit = ",round(x,2),"dB"

Sum of all of the noise temperature contributions Ts =  97 k
The figure of merit =  25.13 dB


## Example 13.5 Page no 652¶

In [9]:
#given
d=41.130383*10**6                                #dismath.tance
c=2.997925*10**8                                 #velocity of light

#calculation
import math
h=c/f                                            #wavelength
x=(4*math.pi*d)/h
Lp=20*math.log10(x)                              #free-space path loss

#result
print"The wavelength is= ",round(h,2)
print"Lp(dB)= ",round(Lp,2),"dB"
#INcorrect answer of h in the textbook

The wavelength is=  0.02
Lp(dB)=  207.81 dB