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FPV Radio Link

What It Is

The radio link is the control link between the pilot and the flight controller.

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Radio transmitter -> RF module -> receiver -> flight controller

It carries stick commands, arm switch, flight mode switch, and telemetry back from the aircraft.

ExpressLRS

TBS Crossfire

TBS Tracer

FrSky

Receiver Protocols

Main Choices

System Common band Main strength Typical protocol to FC
ExpressLRS 2.4 GHz or 900 MHz Open source, low latency, long range CRSF
TBS Crossfire 868/915 MHz Long range and mature ecosystem CRSF
TBS Tracer 2.4 GHz Low latency control CRSF
FrSky 2.4 GHz Older common ecosystem SBUS, F.Port, S.Port
FlySky 2.4 GHz Low cost IBUS
Spektrum 2.4 GHz Common in RC aircraft SRXL2, DSM

Selection Factors

  • Range: long range builds usually prefer 900 MHz systems.
  • Latency: racing and freestyle benefit from faster packet rates.
  • Telemetry: useful for battery voltage, link quality, GPS, and warnings.
  • Antenna size: 900 MHz antennas are larger than 2.4 GHz antennas.
  • Receiver size: micro builds need very small receivers.
  • Ecosystem: transmitter module, receiver availability, firmware tools, and community support matter.
  • Flight controller UARTs: most modern systems need a free UART.