Turn signal, co-channel, adjacent-channel and noise-floor levels into SNR, SINR and the modulation the link can actually hold.
Decibel values cannot be added, so each level is converted to linear power, the interference and noise terms are summed, and the ratio is converted back to dB. Adjacent-channel energy is attenuated by the receiver filter, which is why co-channel interference hurts far more. Survey tools report signal strength, but clients choose their modulation from SINR, which is why a strong -62 dBm signal can still deliver BPSK throughput on a contended channel.
Wireless Interference
SINR = 10·log10(S ÷ (I_co + I_adj + N)) with every level converted from dBm to milliwatts first; adjacent-channel power is reduced by the receiver's rejection figure.
SINR = 10·log10(S ÷ (I_co + I_adj + N)) with every level converted from dBm to milliwatts first; adjacent-channel power is reduced by the receiver's rejection figure. Decibel values cannot be added, so each level is converted to linear power, the interference and noise terms are summed, and the ratio is converted back to dB. Adjacent-channel energy is attenuated by the receiver filter, which is why co-channel interference hurts far more.
Survey tools report signal strength, but clients choose their modulation from SINR, which is why a strong -62 dBm signal can still deliver BPSK throughput on a contended channel.
This calculator takes 5 inputs: Wanted signal level, Strongest co-channel interferer, Strongest adjacent-channel interferer, Adjacent-channel rejection, Noise floor. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.