ELRS Setup Guide for Beginners

Table of Contents

1. What is ExpressLRS
2. Hardware Requirements
3. Radio Transmitter Setup
4. Receiver Installation
5. Binding Process
6. Configuration
7. Troubleshooting

What is ExpressLRS

ExpressLRS (ELRS) is an open-source RC link protocol that has become the gold standard for FPV in 2025. It offers:

• Ultra-low latency: 3-8ms depending on packet rate
• Long range: 30km+ at 900MHz, 10km+ at 2.4GHz
• Low power consumption: Better battery life than competitors
• Free and open-source: No licensing fees, community-driven
• Frequent updates: Regular improvements and new features

Hardware Requirements

For Radio Transmitter

• ELRS-compatible radio (RadioMaster, Jumper, etc.)
• OR external ELRS module for older radios
• USB cable for firmware updates
• Computer with ExpressLRS Configurator

For Drone

• ELRS receiver (2.4GHz or 900MHz)
• Flight controller with UART port
• Antenna appropriate for frequency

Frequency Choice:

• 2.4GHz: Lower latency (3-5ms), shorter range (10km), better for racing
• 900MHz: Better penetration, longer range (30km+), slightly higher latency (5-8ms)

Radio Transmitter Setup

Step 1: Install EdgeTX/OpenTX

Most ELRS radios come with EdgeTX pre-installed. Ensure you have latest version:

1. Download EdgeTX Buddy from edgetx.org
2. Connect radio via USB
3. Update to latest EdgeTX version

Step 2: Flash ELRS Firmware

1. Download ExpressLRS Configurator
2. Select your radio model
3. Choose firmware version (use latest stable)
4. Select binding phrase method (recommended)
5. Flash firmware to radio

Step 3: Configure Radio Model

1. Create new model in EdgeTX
2. Set internal/external RF to ELRS
3. Configure packet rate (250Hz recommended for beginners)
4. Set telemetry sensors

Receiver Installation

Wiring

Receiver → Flight Controller
VCC → 5V (or 3.3V depending on receiver)
GND → GND
TX → RX (UART)
RX → TX (UART)

Important: Cross TX/RX lines! Receiver TX goes to FC RX, and vice versa.

Antenna Placement

• Keep antenna away from carbon fiber (blocks signal)
• Position at 90° angle for best reception
• Use zip ties or heat shrink to secure
• Never fly with damaged antenna

Binding Process

Method 1: Binding Phrase (Recommended)

1. Set same binding phrase in both TX and RX firmware
2. Flash receiver with same binding phrase
3. Power on - auto-binds with matching phrase
4. No manual binding needed!

Method 2: Traditional Binding

1. Put receiver in bind mode (button or CLI command)
2. Put transmitter in bind mode
3. Wait for bind confirmation (LED solid)
4. Power cycle both devices

Configuration

Betaflight Setup

1. Connect to Betaflight Configurator
2. Go to Ports tab
3. Enable Serial RX on UART connected to receiver
4. Go to Configuration tab
5. Set Receiver to "Serial-based receiver"
6. Set Protocol to "CRSF"
7. Save and reboot

Radio Settings

Packet Rate Options:

• 500Hz/250Hz: Best for racing (lower latency)
• 150Hz/100Hz: Good balance (recommended for beginners)
• 50Hz: Maximum range (long-range flying)

Switch Modes:

• Wide (1-bit): ARM/DISARM switches
• Hybrid (6-7 positions): Mode switches
• Configure in EdgeTX mixer

Troubleshooting

No Link / Not Binding

• Verify matching firmware versions on TX and RX
• Check binding phrase matches exactly
• Ensure receiver is powered (check voltage)
• Verify UART wiring (TX↔RX crossed)

Link Quality Issues

• Check antenna is not damaged
• Reduce packet rate for better range
• Increase TX power (be mindful of regulations)
• Ensure antenna is away from carbon/metal

Telemetry Not Working

• Enable telemetry in Betaflight (Configuration tab)
• Check UART TX line is connected
• Verify sensors are discovered in radio
• Update to latest ELRS firmware

Failsafe Configuration

1. In Betaflight, go to Failsafe tab
2. Set failsafe mode to "Drop" or "Land"
3. Configure channel values (throttle to ~1000)
4. Test failsafe by turning off radio

Performance Tips

• Start with 150Hz packet rate, increase when comfortable
• Use telemetry to monitor LQ (Link Quality) and RSSI
• Keep firmware updated on both TX and RX
• Join ExpressLRS Discord for support

Recommended Starting Settings:

• Packet Rate: 150Hz
• Telemetry Ratio: 1:4
• Switch Mode: Hybrid
• TX Power: 100mW (increase only if needed)

--- Last Updated: December 2025