FSPL in link budget

Thread Starter


Joined Jan 26, 2022

I am currently making the link budget for out antenna system, but i am unsure how to account for the FSPL in the link budget.

We have made a link budget that already accounts for the antenna gains, in other words; we have added the dBi gain of the antenna in the total sum.

The formula for FSPL is defined by: 20log(d)+20log(f)-147.55-Gt-Gr. I am wondering about if the antenna gain should be subtracted from the FSPL when theyre already accounted for in the link budget outside the calculation of FSPL. This will, effectively result in adding the antenna gain from the antennas two times, is this the correct way to do it? (theyre directional antennas)

Also, is the connection loss (primarly SMA connectors) per connector or per connection? If i plug in the coax to an SMA connector on the antenna, does this equal say .1dB loss or 2x.1dB loss?

Thank you in advance!


Joined Aug 21, 2008
I believe that you can add the antenna gain to the path loss to come up with a total gain figure and then relate that to he transmitter power and the receiver sensitivity to get an idea as to whether the system will work as needed.