EXPRESS LRS
The modern radio link. Packet rates, telemetry ratios, and full MAVLink integration via the Backpack ecosystem.
High Performance Link
ELRS Foundations: LoRa & CSS Physics
ExpressLRS (ELRS) represents a paradigm shift from traditional FSK (Frequency Shift Keying) radios. It utilizes **LoRa (Long Range)** modulation, a...
Packet Rates, Latency & Range
One size does not fit all. ExpressLRS forces you to choose your **Packet Rate** (Update Frequency). This choice defines the fundamental capabilitie...
MAVLink over ELRS: The 'Airport' Bridge
Traditionally, Long Range pilots needed two radios: Crossfire for Control, and SiK Radio (900MHz) for MAVLink Telemetry. ELRS "Airport" combines th...
The Backpack Architecture: Wi-Fi & ESP8285
The "Backpack" is a secondary processor (ESP8285) inside your ELRS Transmitter module. It acts as a bridge between the ELRS radio link and the outs...
Link Symmetry & TX-as-RX
Standard ELRS systems are **Asymmetric**. The Transmitter (Ground) has 1000mW of power. The Receiver (Air) often has only 100mW (telemetry). This m...
Telemetry Ratios & Bandwidth Math
Unlike traditional radios with fixed telemetry, ELRS allows you to tune the **Uplink/Downlink Balance**. The "Telemetry Ratio" determines how many ...
ArduPilot Integration: Setup & Params
Integrating ELRS with ArduPilot is straightforward, but optimizing it for MAVLink requires specific settings. The default "Auto-Detect" works for R...
Advanced Modes: F, D, and K
ELRS is not static. It supports multiple modulation modes tailored for different environments. **F-Mode** (FLRC) is for pure racing speed. **D-Mode...
The Yaapu Problem & The HUD Solution
For years, ArduPilot users have relied on the **Yaapu Telemetry Script** to see flight data on their radio screens. However, as pilots move to **MA...