TBS Crossfire – LQ monitoring 

While you are flying it´s important to have a eye on your rc link.

If you are not using a osd there is a alternativ way to get noticed – with voice warnings from your taranis.


  • Taranis x9d(+)/ X7/ x10
  • OpenTX 2.2 (or higher)
  • Crossfire 1.65 (or higher)
  • Crossfire receiver with enabled telemetry
  • If you have problems with the crsf telemetry – here is how it can be fixed


The Crossfire can output the LQ with wider ranger (0-300%) which can´t be interpreted by OpneTX.

Therefore the splitet it in to two sensors: RLQY and RFMD.

  • RLQY: Received link quality - the ammount of the transmittet signal recived by the reciver
  • RFMD: Received frequenzy mode - to scale the 300% Crossfire LQ down to 3x 100%

RFMD 2 = 150Hz Mode

RFMD 1 = 50Hz Mode

RFMD 0 = 4Hz Mode (forced telemetry)

LQ = 0-100%

While the Crossfire is in 150Hz mode the lq doesn´t matther so there s no need to monitore the link quality. When it switches to the 50Hz mode the critical level is at 70%.


The setup for the radio is relay simple:

What they mean:
L01: Monitors the Crossfire frequency mode, activated when it´s not in 150Hz mode

L02: Activ when the Link quality drops below 80% (pre warning) AND 50 or 4 Hz mode is activ

L03: Same as L02 but with the critical warning level at 70%

L02 and L03 also got a smal delay (0.5s) to avoid warnings when the signal is only bad for a short moment.

With the logical switches the voice alerts will be triggert every time the are activ.

What they mean:
SF1: when L02 is activ, plays the selected track ones -but not at the startup

SF2: same as SF1 for the critical warning

Why to use Link quality instead of RSSI?
LQ is much more easy to monitor than RSSI. To knwo the range limit based on RSSI the noise floor need to be known as well. Noise floor depends on environment and on the components built-in the airframe. If you are not so familiar how RSSI works we recommend to use LQ.

Written by: kamikatze-fpv