# Chapter 14 Antennas and Wave Propogation¶

## Example 14.1 page no 544¶

In :
#Given
f=310.0*10**6

#Calculation
import math
len1 =(492*0.97)/f
len2 =(492/f)*0.8
len3 =(984/f)*0.73
z1 =120*log(35/2.0)
len4 =234/f
z2  = 73/2.0

#Result
print"(a) The length and radiation resistance of the dipole are ",round(len1*10**6,2),"feet and 73 ohm respectively"
print"(b) The length of the folded dipole are ",round(len2*10**6,2),"feet"
print"(c) The length and radiation resistance of the bow tie antenna are ",round(len3*10**6,1),"feet and ",round(z1,1),"ohm respectively"
print"(d) The length and radiation resistance of the groun plane antenna are ",round(len4*10**6,3),"feet and",z2,"ohmrespectively"

(a) The length and radiation resistance of the dipole are  1.54 feet and 73 ohm respectively
(b) The length of the folded dipole are  1.27 feet
(c) The length and radiation resistance of the bow tie antenna are  2.3 feet and  343.5 ohm respectively
(d) The length and radiation resistance of the groun plane antenna are  0.755 feet and 36.5 ohmrespectively


## Example 14.2 Page no 553¶

In :
#Given
gain=14
len=250
attn_100=3.6
f =220*10
pin =50
p =0.126

#Calculation
pout =pin*p
line_loss =pin-pout
pwr_ratio = 25.1
ERP = pwr_ratio*pout

#Result
print"(a) The transmission line loss is ",line_loss
print"(b) Effective raduated power is ",round(ERP,1),"W"

(a) The transmission line loss is  43.7
(b) Effective raduated power is  158.1 W


## Example 14.3 Page no 556¶

In :
#Given
Z0 =50
Zl =172
f =460.0*10**6
VF =0.86

#Calculation
len =(246/f)*VF

#Result
print"The length of the impedance matching section needed for the Q section is ",round(len*10**6,2),"feet"

The length of the impedance matching section needed for the Q section is  0.46 feet


## Example 14.4 Page no 557¶

In :
#Given
f = 460.0*10**6
VF = 0.66

#Calculation
len = (246/f)*VF

#Result
print"The length of impedance matching section is ",round(len*10**6,3),"feet"

The length of impedance matching section is  0.353 feet


## Example 14.5 Page no 567¶

In :
#Given
ht =275
hr =60
f=224.0*10**6
pt=100
Gt = 26
Gr = 3.27

#Calculation
D =((2*ht)**0.5+(2*hr)**0.5)*1.61
lamda = 300/f
Pr = (pt*Gt*Gr*lamda**2)/(16*3.14**2*D**2)

#Result
print"(a) The maximmum transmitting distance is ",round(D,1),"kilometer"

(a) The maximmum transmitting distance is  55.4 kilometer