diff --git a/RFM69.h b/RFM69.h
index 99a0a97..66be994 100644
--- a/RFM69.h
+++ b/RFM69.h
@@ -191,7 +191,7 @@ class RFM69 {
     void setFrequency(uint32_t freqHz);
     void encrypt(const char* key);
     void setCS(uint8_t newSPISlaveSelect);
-    int16_t readRSSI(bool forceTrigger=false); // *current* signal strength indicator; e.g. > 100dBm says the frequency channel is free + ready to transmit
+    int16_t readRSSI(bool forceTrigger=false); // *current* signal strength indicator; e.g. < -90dBm says the frequency channel is free + ready to transmit
     void promiscuous(bool onOff=true);
     virtual void setHighPower(bool onOFF=true); // has to be called after initialize() for RFM69HW
     virtual void setPowerLevel(uint8_t level); // reduce/increase transmit power level