Electronics and Communication Engineering - Satellite Communication - Discussion
Discussion Forum : Satellite Communication - Section 1 (Q.No. 5)
5.
A 20 m antenna gives a certain uplink gain at frequencies of 4/6 GHz. For getting same gain in the 20/30 GHz band, antenna size required is metre.
Discussion:
12 comments Page 1 of 2.
Anurag Nande said:
1 decade ago
Antenna diameter (d) is inversely proportional to the operating frequency (f).
So d = k*(1/f).
Note :- Here k is constant.
For up link f = 4GHz for down link f = 6GHz.
d = k*1/4 d = k*1/6.
d/5 = k*1/(4*5).
d/5 = k*1/(6*5).
d/5 = k/20 ---(1)
d/5 = k/30----(2).
So the resultant size of antenna from equation (1) and (2):
Size = d/5 = 20/5 = 4m.
Size = 4m.
So d = k*(1/f).
Note :- Here k is constant.
For up link f = 4GHz for down link f = 6GHz.
d = k*1/4 d = k*1/6.
d/5 = k*1/(4*5).
d/5 = k*1/(6*5).
d/5 = k/20 ---(1)
d/5 = k/30----(2).
So the resultant size of antenna from equation (1) and (2):
Size = d/5 = 20/5 = 4m.
Size = 4m.
(3)
Zarana said:
10 years ago
How put 5?
We need height of 20/30 frequency. So do 4*5/6*5 & dived by 5 to 20 meter height?
So answer is 4?
We need height of 20/30 frequency. So do 4*5/6*5 & dived by 5 to 20 meter height?
So answer is 4?
(3)
Vaishu said:
6 years ago
How 5?
(3)
THANAM SIVA said:
8 years ago
Thanks for explaining it.
(2)
Nirav Solanki said:
1 decade ago
Here frequency is multiplied by 5 means the wavelength is divided by 5.
Now length of antenna is directly proportional to the half of the wavelength. So the ultimate length of antenna is divided by 5.
Now length of antenna is directly proportional to the half of the wavelength. So the ultimate length of antenna is divided by 5.
(1)
Suresh said:
10 years ago
Thanks to explaining all of these.
(1)
Indu said:
9 years ago
How put 5?
(1)
Prakhar said:
1 decade ago
Antenna diameter is inversely proportional to the operating frequency.
Nisha said:
1 decade ago
Lambda = c/f.
If f' = 5f.
Then lambda' = lemda/5 = height of antenna = 4m.
If f' = 5f.
Then lambda' = lemda/5 = height of antenna = 4m.
Shreya said:
1 decade ago
20m antenna-----4/6GHZ-----multiply by 5.
?---------------20/30GHZ.
4*5/6*5-----20/5=4m.
?---------------20/30GHZ.
4*5/6*5-----20/5=4m.
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