Calculations: System Operating Margin (SOM)

The System Operating Margin can be calculated by the formula listed below. SOM is the difference between the signal a radio is actually receiving vs. what it needs for good data recovery (i.e. receiver sensitivity). For further information on this formula, please review the figure below.
Note: This calculator is valid for frequencies below 6 GHz. The final values represent a first order approximation and should only be used as a guide. No guarantees or warranties are implied accordingly. For a more detailed analysis, contact your Terabeam Wireless account manager.

* denotes a required field

Calculation Input
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

Calculation Results
Free Space Loss	dB	Rx Signal Level	dBm
Theoretical System Operating Margin		dB

System Operating Margin Example

Notes:

• When calculation the system operating margin and you are using an amplifier on the receive side, do not add the amps RX gain to the SOM equation. To learn why, visit our RF Link and Amplifier FAQs.

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