Wireless link budget

Free-space path loss, EIRP, fade margin and the Fresnel clearance a link needs to behave.

Link

Frequency (MHz)
Distance (km)
Tx power (dBm)
Tx antenna (dBi)
Rx antenna (dBi)
Tx cable loss (dB)
Rx cable loss (dB)
Rx sensitivity (dBm)
Path loss121.7 dB
EIRP43.0 dBm
Received-55.7 dBm
Fade margin24.3 dB20 dB is the usual target

Assessment

excellent
Fresnel zone radius
8.04 m
Required clearance (60%)
4.82 m

Obstructions inside the Fresnel ellipsoid degrade the link even with clear line of sight — which is why a link you can see straight down can still perform badly.

  • EIRP 43.0 dBm is above 36 dBm — check the limit for this 5 GHz sub-band and region.