What is the link margin in a system with a transmit power level of 10 W (+40 dBm), a system antenna gain of 10 dBi, a cable loss of 3 dB, a path loss of 136 dB, a receiver minimum discernable signal of -103 dBm, and a required signal-to-noise ratio of 6 dB?

Erklärung

The signal reaching the receiver is the transmit power plus the antenna gain less the cable and path losses: +40 dBm + 10 dBi − 3 dB − 136 dB = −89 dBm. The level required is the receiver detection threshold plus the wanted signal-to-noise ratio, −103 dBm + 6 dB = −97 dBm, so the margin is −89 − (−97) = +8 dB.