Tera Single TTL 3DRobotics 3DR Radio Telemetry Kit 915Mhz Module for APM APM2.5 2.6 Pix Range of approx 1 mile with supplied antennas. Demonstrated range of several kilometers with a small omni antenna. Can be used with a bi-directional amplifier for even more range. MAVLink protocol framing and status reporting. Frequency hopping spread spectrum (FHSS). Adaptive time division multiplexing (TDM). 915Mhz frequency band. Receiver sensitivity to -117 dBm. Transmit power up to 20dBm (100mW). Transparent serial link. Antenna connectors: RP-SMA connector.