What is the sensitivity of a repeater?

The sensitivity of a repeater is the smallest signal value it can retransmit while maintaining a signal/noise ratio sufficient for proper operation of the signal.

It is directly linked to the concept of noise figure and bandwidth of the signal used.

In the case of a GSM signal, a conventional repeater has a sensitivity of around -110 dBm. In the case of a TETRA or TETRAPOL repeater, this value is about -120 dBm.

Because the gain of a repeater can not exceed ~ 90dB, the sensitivity of a repeater is rarely an important parameter because the signals it has to process have a value typically greater than -80 dBm.