# HOW TO INTERACT WITH FSL EQUATION

• posted

Hi folks,
Sorry for this basic question, I have no experience with wireless
issues, but I am learning and trying to understand the theory of
antennas:
My question is what is the FSL really means?
I cam to know that FSL = 36.6 + 20 LOG F + 20 LOG D
For 5.8 GHZ and 14 miles this would yield a 133.86 db, now is this
133.86 is attenuation? Is it related to the receiver sensitivity at the
destination? How can I use this number?
Let me think loud, I understand it this way
If I have EIRP of 36 dB in the transmission end, then this 36 db will
be subtracted from the 133.86, hence I will get a -97.86 db, so my
receiver should be sensitive enough to receive a power of 1.99 e-10
Watts.
Thanks,
ConceptZone
• posted
Free Space Loss. It's really a measure of inverse square law. Double the distance and you loose 4 times (-6dB) the power. I don't wanna go into the field equations, but double the frequency and you also lose 4 times the power. See the bottom half of: