Installing the Receiver

The receiver (RX) is small but its placement and antenna routing have a significant impact on your radio link quality.

Mounting Location

Where to Put It

• Inside the stack: Some pilots tuck the receiver between the ESC and FC or on top of the FC. Compact but can pick up electrical noise.
• On top of the FC: Double-sided tape on the FC’s top surface. Easy access.
• Under the top plate: Protected from crashes, antennas route out the back.
• On the rear of the frame: Common for diversity receivers with two antennas. Good separation from electronics.

Key Considerations

• Away from the VTX: The VTX transmits strong RF that can desensitize the receiver
• Away from motor wires and ESC: Electrical noise reduces receiver sensitivity
• Accessible: You may need to press the bind button or update firmware
• Protected: Inside the frame is better than exposed on top where crashes can damage it

Mounting Methods

• Double-sided foam tape: Most common. Holds well, easy to remove.
• Hot glue: More permanent. A dab on the corners holds it securely.
• Zip tie: Through mounting holes if the receiver has them.
• Conformal coat the receiver: Before mounting, coat the receiver PCB with conformal coating to protect against moisture and shorts from conductive debris.

Wiring

ELRS / Crossfire (CRSF Protocol)

Four wires:

Wire	Connect To
5V	FC 5V pad
GND	FC GND pad
TX (receiver transmit)	FC UART RX pad
RX (receiver receive)	FC UART TX pad

Note the crossover: receiver TX goes to FC RX, and receiver RX goes to FC TX. This is because one device’s transmit is the other device’s receive.

SBUS (FrSky)

Three wires:

Wire	Connect To
5V	FC 5V pad
GND	FC GND pad
SBUS	FC UART RX pad (SBUS uses inverted serial)

Which UART?

Choose an available UART on your FC. Check the FC’s documentation for which pads correspond to which UART number. Most FCs label them (TX1/RX1, TX2/RX2, etc.).

In Betaflight Configurator’s Ports tab, enable “Serial RX” on the UART number you wired the receiver to.

Antenna Routing

Antenna placement is critical for good radio link performance.

Single Antenna Receivers

• Route the antenna away from the frame, pointing rearward and upward
• Keep at least 1-2cm of the antenna element past the carbon fiber frame
• Avoid running the antenna parallel to carbon fiber (it blocks RF)

Diversity Receivers (Two Antennas)

• Route antennas at approximately 90° to each other (e.g., one pointing up, one pointing sideways)
• This provides coverage in all orientations
• Use TPU antenna tubes zip-tied to the rear standoffs

Antenna Protection

• TPU tubes: 3D-printed tubes that hold antennas at the correct angle and protect them in crashes
• Heat shrink: Over the base of wire antennas for strain relief
• Hot glue: A dab at the antenna solder joint prevents the wire from breaking off in crashes

What to Avoid

• Don’t coil excess antenna wire — it creates interference patterns
• Don’t tape the antenna flat against the carbon fiber frame — carbon blocks the signal
• Don’t route antennas near the VTX antenna — interference
• Don’t let antennas dangle in the prop path — they’ll get cut

Betaflight Configuration

After physical installation:

1. Ports tab: Enable “Serial RX” on the correct UART
2. Configuration tab:
   • Receiver Mode: Serial
   • Serial Receiver Provider: CRSF (for ELRS/Crossfire) or SBUS (for FrSky)
3. Receiver tab:
   • Verify all channels respond to stick movements
   • Check channel map (AETR for CRSF, TAER for some SBUS setups)
   • All channels should center at ~1500 and range ~1000-2000

Binding

If using binding phrase (ELRS), the TX and RX auto-connect when powered on with matching phrases. No manual binding needed.

For manual binding:

1. Power on the RX in bind mode (method varies: hold button, 3 quick power cycles, etc.)
2. Put your TX in bind mode
3. Wait for connection confirmation (usually LED changes from flashing to solid)
4. Power cycle both — they should reconnect automatically

→ See ExpressLRS for ELRS-specific binding and setup.