System Operating Margin Calculator

System Operating Margin is the difference between the signal a radio is actually receiving vs. what it needs for good data recovery (i.e. receiver sensitivity). This calculator is valid for frequencies below 6 GHz. All fields marked with an asterisk (*) are required.

* denotes required field
*Operating Frequency:	MHz		*Distance Between Antennas:	Miles
*Tx Antenna Gain:	dBi		*Rx Antenna Gain:	dBi
*Tx Cable Loss:	dB		*Rx Cable Loss:	dB
*Tx Power:	dBm		Rx Sensitivity:	dBm

Note: The final values represent a first order approximation and should only be used as a guide. No guarantees or warranties are implied accordingly.

Free Space Loss (FSL) = 20Log₁₀(MHz) + 20Log₁₀(Distance in Miles) + 36.6

Rx Signal Level = (Tx Power) - (Tx Cable Loss) + (Tx Antenna Gain) - (FSL) + (Rx Antenna Gain) - (Rx Cable Loss)

System Operating Margin (SOM) = Rx Signal Level - Rx Sensitivity