SENTHIL KUMAR
Banned
- Joined
- 13 May 2015
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An antenna focuses the radio waves in a certain direction. Usually, this is called the main direction. Because of that, in other directions less energy wil be emitted. The gain of an antenna, in a given direction, is usually referenced to an (hypothetical) isotropic antenna, which emits the radiation evenly strong in all directions. In this case the antenna gain (Gi) is often specified in dB, or decibels over isotropic.
Here , the formula for calculating the gain of antenna. This formula is applicable for prime focus antenna. We give the following parameters , then calculate the antenna gain in dB.
Antenna gain = 4 * π ( D * E ) / R*R.
π = 22/7 = 3.141.
D = Diameter of antenna – 1800mm ( 6 feet prime focus antenna).
E = Efficiency of antenna = 70 % to 80 % ( 100 % efficiency antenna is not possible.)
R = speed of light / frequency * frequency.
speed of light = 3*1000000000 = 3000000000
Frequency = 3900 Mhz. ( example).
Now apply the values in formula.
4 * π ( D * E ) = 4*3.141 ( 1800 * 70 ) = 1583064
R2 = (3000000000 / 3900*3900)2 = 38901
Antenna gain = 1583064 / 38901 = 40.69 dB
ANTENNA GAIN IS = 40.69 dB.
Normally the Gain of prime focus dish antenna is in between the range of 35 dB to 45 dB.
An antenna focuses the radio waves in a certain direction. Usually, this is called the main direction. Because of that, in other directions less energy wil be emitted. The gain of an antenna, in a given direction, is usually referenced to an (hypothetical) isotropic antenna, which emits the radiation evenly strong in all directions. In this case the antenna gain (Gi) is often specified in dB, or decibels over isotropic.
Here , the formula for calculating the gain of antenna. This formula is applicable for prime focus antenna. We give the following parameters , then calculate the antenna gain in dB.
Antenna gain = 4 * π ( D * E ) / R*R.
π = 22/7 = 3.141.
D = Diameter of antenna – 1800mm ( 6 feet prime focus antenna).
E = Efficiency of antenna = 70 % to 80 % ( 100 % efficiency antenna is not possible.)
R = speed of light / frequency * frequency.
speed of light = 3*1000000000 = 3000000000
Frequency = 3900 Mhz. ( example).
Now apply the values in formula.
4 * π ( D * E ) = 4*3.141 ( 1800 * 70 ) = 1583064
R2 = (3000000000 / 3900*3900)2 = 38901
Antenna gain = 1583064 / 38901 = 40.69 dB
ANTENNA GAIN IS = 40.69 dB.
Normally the Gain of prime focus dish antenna is in between the range of 35 dB to 45 dB.
hya
