I added this to my sketch and observed serial output:
Serial.print(transportGetReceivingRSSI()); Serial.println(" :transportGetReceivingRSSI()");
Serial.print(transportGetSendingRSSI()); Serial.println(" :transportGetSendingRSSI()");
Serial.print(transportGetReceivingSNR()); Serial.println(" :transportGetReceivingSNR()");
Serial.print(transportGetSendingSNR()); Serial.println(" :transportGetSendingSNR()");
Serial.print(transportGetTxPowerLevel()); Serial.println(" :transportGetTxPowerLevel()");
Serial.print(transportGetTxPowerPercent()); Serial.println(" :transportGetTxPowerPercent()");
Serial.print(transportInternalToRSSI(_transportSM.uplinkQualityRSSI));Serial.println(" :transportInternalToRSSI(_transportSM.uplinkQualityRSSI)");
I don't know if it's a valid way to check the values.