Receiver

The Receiver tab configures and verifies your RC link: which channel drives which axis, how far each stick travels, which way each axis moves, the bind, RSSI reporting, and flight-mode assignment. A live monitor shows the incoming channels in real time.

Live monitor

The left column shows live RC input — a stick/craft preview plus per-channel bars — so you can confirm the receiver is talking to the flight controller before configuring anything. If it reads “No RC telemetry”, the receiver isn’t being seen yet; check the serial port assignment (see Ports & Serial) and the bind.

Mapping

Tells the flight controller which physical channel carries roll, pitch, throttle, and yaw (RCMAP_*). Use the guided, one-axis-at-a-time mapping: move the prompted stick and the app detects which channel responded.

Endpoints

Captures the minimum, centre (trim), and maximum of each channel (RCn_MIN / RCn_TRIM / RCn_MAX) by moving the sticks to their extremes.

Channel direction

Under Endpoints, the Channel direction check verifies each axis moves the right way. Move each stick the way it’s labelled — roll right, pitch up, throttle up, yaw right — and the app reads the live channel and reports correct or backwards for that axis.

Note

Detection is reversal-aware: it reflects what ArduPilot will actually do with the current RCn_REVERSED setting. Pitch is the classic case — most Mode-2 transmitters need RC2_REVERSED set so that pulling back commands pitch-up.

Any axis that reads backwards shows a one-click Reverse button, which stages an RCn_REVERSED change like any other edit (apply it, then move the stick again to confirm it now reads correct).

Warning

In Guided Setup, the Receiver step blocks sign-off until every axis reads correct. In the regular Receiver tab this check is advisory.

Bind (ELRS / CRSF)

The Bind RX button (under the live monitor) puts an ExpressLRS or Crossfire receiver into bind mode. It sends MAV_CMD_START_RX_PAIR; ArduPilot forwards the bind command to the receiver over the CRSF link. Put your transmitter / ELRS module into bind mode at the same time — the receiver’s LED confirms when it pairs. (The flight controller does not report bind completion, so confirm at the receiver itself.)

RSSI and link quality

RSSI is how the vehicle learns how good its own RC link is — it drives the OSD signal readout, the logged link quality, and your judgement about how far out to fly. It does not arrive automatically: ArduPilot has to be told where to get it, with RSSI_TYPE. Getting this wrong is the usual reason an OSD shows a flat 0 % or a stuck 100 %.

The Advanced task on this tab has a Receiver signal setup card with the source dropdown, the channel settings, and a live RX RSSI readout so you can confirm the choice reads sensibly before you fly. The same source dropdown also appears on the Config tab under RC → Receiver & signal.

Pick the source that matches how your receiver reports:

Value	Source	Use it when
0	Disabled	No RSSI reporting at all.
1	Analog pin	The receiver outputs an analog RSSI voltage to a spare ADC pin. Needs RSSI_ANA_PIN and the RSSI_PIN_LOW / RSSI_PIN_HIGH voltage endpoints, which are not on this card — set them from the Parameters (Expert) tab.
2	RC channel PWM	The receiver maps RSSI onto a spare RC channel as a PWM value. Set RSSI_CHANNEL to that channel and RSSI_CHAN_LOW / RSSI_CHAN_HIGH to the PWM it produces at worst and best signal.
3	Receiver protocol	The normal choice for CRSF / ExpressLRS, FPort, and Ghost. The RC protocol itself carries RSSI, so nothing else needs configuring. This is also the only source that yields a separate link quality figure.
4	PWM input pin	The receiver emits RSSI as a PWM duty cycle on a pin.
5	Telemetry radio RSSI	RSSI is taken from the RADIO_STATUS messages a MAVLink telemetry radio sends. See below.

MAVLink-carried RC (mLRS and similar)

A link like mLRS carries the RC channels inside MAVLink rather than over a dedicated RC serial protocol: the port is set to MAVLink2, and the RC channels arrive as RADIO_RC_CHANNELS messages, enabled by the MAVRadio bit — bit 16 — of RC_PROTOCOLS.

For that setup, RSSI_TYPE = 3 (Receiver protocol) reads nothing. The MAVLink-radio RC backend hands ArduPilot the channel values and the failsafe flag and nothing else; there is no RSSI field in that path, so the firmware records it as unknown. The link’s signal strength instead arrives separately, in the radio’s own RADIO_STATUS messages.

So set RSSI_TYPE to 5 — Telemetry radio RSSI. ArduPilot then takes the RSSI byte out of the most recent RADIO_STATUS, scales it to 0–100 %, and falls back to 0 if the radio reports “unknown” or stops sending for five seconds.

Note

Value 5 works on ArduPilot 4.6 as well as 4.7, but the configurator’s parameter metadata only lists it for 4.7 firmware. On an older build the dropdown stops at 4 and typing 5 is flagged as out of range — use Override and write anyway in the Parameters (Expert) tab to set it. The firmware accepts it.

Flight modes

Assigning flight modes to a transmitter switch has its own tab — see Flight Modes. The Flight Mode task on this tab is the same assignment with a live switch exerciser attached, so you can flick through the detents and watch which slot each one selects. See also Guided Setup for the mode-assignment step.