Translations:KAVAN V20 + ETHOS™ - User manual/1005/en

From KAVAN RC Wiki

RSSI

Receiver Signal Strength Indicator (RSSI): A value transmitted by the receiver in your model to your transmitter that indicates how strong the signal is that is being received by the model. Warnings can be set up to warn you when it drops below a minimum value, indicating that you’re in danger of flying out of range. Factors affecting the signal quality include external interference, excessive distance, badly oriented or damaged antennas etc.