Why the parabbolic antenna is big size while it is used for

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anwer_sbh

Joined: 11 Jul 2006
Posts: 92
Location: iraq

22 Sep 2006 19:17 Why the parabbolic antenna is big size while it is used for

Why the parabbolic antenna is big size while it is used for high frequencies (the size must be decreased as the frequency increased)?

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timo67

Joined: 21 Sep 2006
Posts: 69
Helped: 3

22 Sep 2006 19:44 Why the parabbolic antenna is big size while it is used for

When you use parabolic antenna the frequency of the signal is about f= 10 GHz
The wavelength is given by the formula :
Lambda = c / F
C is the speed of the light = 300000 Km/s
Lambda is near 3cm
That is why the size of the parabolic antenna has nothing to do with the frequency
On the other hand the size of the parabolic antenna depends on the power of the emitted signal
If the satellite emit a weak signal or is not oriented to your region you need a very barge diameter of parabolic antenna to collect more signal and et better Signal/ Noise ratio

mahdithdn

Joined: 18 Aug 2004
Posts: 101
Helped: 13
Location: Iran

25 Sep 2006 6:40 Why the parabbolic antenna is big size while it is used for

Hi
first of all, if you use parabolic antenna in low frequency, it should be very huge.
second, do you compare it with small dipole antenna?!!! small dipole (monopole) antenna is complitely inefficiet while parabolic antenna is much more efficient.
regards