import math ht=36000 #height of satellite in km f=4000 #freq used in MHz Gt=15.0 #transmitting antenna gain Gr=45.0 #receiving antenna gain #A) Determination of free−space transmission loss L=32.5+20*math.log10(ht)+20*math.log10(f) L=round(L,2) print 'The free−space transmission loss is',L #B) Determination of received power Pr Pt=200.0 #transmitted power in watt Pr_Pt=Gt+Gr-L #power ration in dB Pr_Pt_watt=10**(Pr_Pt/10) #power ratio in watts #Therefore Pr=Pt*Pr_Pt_watt*10**12 Pr=round(Pr,2)*10**-12 print 'The received power',Pr,'watts'
The free−space transmission loss is 195.67 The received power 5.42e-12 watts
import math from math import pi,sqrt Pr=10.0 #radiated power in watt f=150.0 #freq used in MHz d2=50.0 #distance of dipole in km #Therefore open−ckt voltage induced is given as Vs=sqrt(30*Pr*1.64)/(d2*10**3)*2/pi Vs=Vs*10**6 Vs=round(Vs,2) print 'The open−ckt voltage induced is',Vs,'uV'
The open−ckt voltage induced is 282.42 uV
import math from math import pi Pt=100 #transmitted power f=150 #freq used in MHz d1=20 #height of transmitting antenna in m Gt=1.64 #transmitting antenna gain ht=2 #height of receiving antenna in m d2=40 #distance in km c=3*10**8 wl=c/(f*10**6) E0=sqrt(30*Pt*Gt) #Field strength at a receiving antenna is ER=(E0*4*pi*d1*ht)/(wl*(d2*10**3)**2) ER=ER*10**6 ER=round(ER,2) print 'Field strength at a receiving antenna is',ER,'uV/m'
Field strength at a receiving antenna is 11.02 uV/m
import math from math import sqrt ht1=100 ht2=60 #antenna heights in ft dmax_miles=sqrt(2*ht1)+sqrt(2*ht2) dmax_miles=round(dmax_miles,2) print 'The maximum range is',dmax_miles,'miles'
The maximum range is 25.1 miles
import math from math import pi ht=200 #virtual height in km a=6370 #in km B_degree=20 B_rad=20*pi/180 #angle of elevation in degree #The flat−earth approximation gives d=2*ht/math.tan(B_degree) d=round(d,1) print 'd=',d,'km' #By using radian measures for all angles d=2*a*(((pi/2)-B_rad)-(math.asin(a*math.cos(B_degree)/(a+ht) ))) d=round(d,1) print 'd=',d,'km'
d= 178.8 km d= 10382.4 km
import math from math import pi,sqrt conductivity = 4 #measured in S/m rel_permittivity =80 u=4*pi*10**-7 f1=100 #measured in Hz f2=10**6 #measured in Hz #A)first it is necessary to evaluate the ratio of conductivity /w*rel permittivity w1=2*pi*f1 r=conductivity/w1*rel_permittivity #Therefore we have to use following eq to calculate the attenuation coeff as a=sqrt(w1*conductivity*u/2) a=round(a,3) print 'The attenuation coeff is',a,'N/m' #By using the conversion factor N=8.686 dB a_dB=a*8.686 a_dB=round(a_dB,3) print 'The attenuation coeff in dB/m is',a_dB,'dB/m' w2=2*pi*f2 r=conductivity/w2*rel_permittivity a=sqrt(w2*conductivity*u/2) a=round(a,1) print 'The attenuation coeff is',a,'N/m' #By using the conversion factor 1N=8.686 dB a_dB=a*8.686 a_dB=round(a_dB,1) print 'The attenuation coeff in dB/m is',a_dB,'dB/m'
The attenuation coeff is 0.04 N/m The attenuation coeff in dB/m is 0.347 dB/m The attenuation coeff is 4.0 N/m The attenuation coeff in dB/m is 34.7 dB/m