whypeople are calling path loss as freespace path loss

[bimsriraj]

free space path loss

what is meant by free space path loss?

 

[biff44]

path profile for free space optics

free space path loss is what you get when your transmit and receive antennas are ontop of 300 foot towers with nothing in between but air, and assume no multipath. It is easy to calculate.

Actual path loss, with trees and buildings and reflections, is a much higher number. Unfortunately it is the actual path loss that you deal with in communications networks.

 

[mauloftin]

free space loss atmosphere loss

what is meant by free space path loss?

Hi,

may be there is answer https://en.wikipedia.org/wiki/Free-space_path_loss , or not ?


one part of path loss is freespace loss

 

[bimsriraj]

path loss not free space

free space path loss is what you get when your transmit and receive antennas are ontop of 300 foot towers with nothing in between but air, and assume no multipath. It is easy to calculate.

Actual path loss, with trees and buildings and reflections, is a much higher number. Unfortunately it is the actual path loss that you deal with in communications networks.

.

no, freespace loss may be due atmopseher is absorbing less signal, so signal will be behaving same as like vaccuum.thats why may be people are calling as free space path loss

 

[mauloftin]

free space loss 4pi

free space path loss is what you get when your transmit and receive antennas are ontop of 300 foot towers with nothing in between but air, and assume no multipath. It is easy to calculate.

Actual path loss, with trees and buildings and reflections, is a much higher number. Unfortunately it is the actual path loss that you deal with in communications networks.

.

no, freespace loss may be due atmopseher is absorbing less signal, so signal will be behaving same as like vaccuum.thats why may be people are calling as free space path loss

Fresspace loss is not absorbing signal !

"free-space path loss (FSPL) is the loss in signal strength of an electromagnetic wave that would result from a line-of-sight path through free space"

 

[vfone]

free space loss versus loss in air

...so signal will be behaving same as like vaccuum

A signal behave like a vacuum !!?? Probably we can get even a Black Hole

 

[LvW]

wave path loss free air

May I try to give an additional explanation ?
Of course the answer from BIF44 is correct, but perhaps not easy to understand as it is not a real definition.
An ideal isotropic antenna would emit all the input power P equally in all directions.
Therefore, the portion in "only one" direction from this antenna is the density D:
D=P/4Pi*r² (r=distance). This is something like a spreading effect.
This has to be multiplied with the antenna parameters which involve gain and frequency. As the result the "spreading" effect (which has nothing to do with any kind of attenuation) is lowered and leads to actual "loss" figures.
Atmospheric and other parasitic influences have to be considered separately.

 

[mauloftin]

path profile loss

May I try to give an additional explanation ?
Of course the answer from BIF44 is correct, but perhaps not easy to understand as it is not a real definition.
An ideal isotropic antenna would emit all the input power P equally in all directions.
Therefore, the portion in "only one" direction from this antenna is the density D:
D=P/4Pi*r² (r=distance). This is something like a spreading effect.
This has to be multiplied with the antenna parameters which involve gain and frequency. As the result the "spreading" effect (which has nothing to do with any kind of attenuation) is lowered and leads to actual "loss" figures.
Atmospheric and other parasitic influences have to be considered separately.

I think, that your answer is same as there: https://en.wikipedia.org/wiki/FSPL

the "loss" mean, that power is spread into the space.... not that power is absorbed.
I hope, that "bimsriraj" understand

 

[bimsriraj]

free-space and losses

...so signal will be behaving same as like vaccuum

A signal behave like a vacuum !!?? Probably we can get even a Black Hole

what i mean is signal exactly behave when travelling in a vacuum space.

 

[Kazzam]

free space loss definition

Path loss is the reduction in power density of an electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a telecommunication system and very majorly used in antennas systems.....
This term is commonly used in wireless communications and signal propagation. Path loss may be due to many effects, such as free-space loss, refraction, diffraction, reflection. So being the reason it may be also called a s freespace path loss.....

what is meant by free space path loss?