Can we apply Friss equation to find field strength at the receiving point....

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The Friss equation is primarily used to calculate path loss between two antennas in free space, but it does not directly provide field strength. For space wave propagation, the electric field can be calculated using the formula E = (7 * sqrt p / d^2) in volts per meter. While the Friss equation can help determine the power received by an antenna, it requires additional considerations for ground reflection and antenna type, such as monopoles. The discussion emphasizes the relationship between power, the Poynting vector, and electric field strength. Overall, while the Friss equation is useful, it must be applied with caution in practical scenarios.
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Can we apply friss equation to find field strength at the receiving point for space wave propagation?
 
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aashna said:
Can we apply friss equation to find field strength at the receiving point for space wave propagation?
The Friss formula gives the path loss between two antennas of specified aperture when in free space, so it does not directly give the field strength. The easiest formula for radiation from a dipole in free space is: E = (7* sqrt p / d^2 ) in volts per metre, volts, metres, watts.
The formula is not applicable for propagation over ground.You can introduce factors for gain and ground reflection if required. Be careful if a monopole antenna.
 
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tech99 said:
The Friss formula gives the path loss between two antennas of specified aperture when in free space, so it does not directly give the field strength. The easiest formula for radiation from a dipole in free space is: E = (7* sqrt p / d^2 ) in volts per metre, volts, metres, watts.
The formula is not applicable for propagation over ground.You can introduce factors for gain and ground reflection if required. Be careful if a monopole antenna.
thank you!
but sir friss equation can easily give us the power received by the antenna and we know the relation between power,poyenting vector ,and electric field. power_received=poyenting_vector*effective_aprerture and poyenting_vector=(electric_field)^2*η. So now can we calulate electrc field?. The mode of propagation is space wave.
 
Agree, but you asked if the Friss formula gave field strength. The formula I have given seems to be quite simple.
 
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tech99 said:
Agree, but you asked if the Friss formula gave field strength. The formula I have given seems to be quite simple.
yeah!
i like it.
 

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