EXPRESSLRS TRIVIA 1 / 8
ELRS
What is ELRS?

ExpressLRS

An open-source RC link system designed for long range and low latency — built by the community, for the community.

first commit 2019 → present
Origin

Born in 2019

ELRS originated as a GitHub project focused on beating commercial links at long-range FPV. It grew into one of the most popular open-source RC protocols worldwide.

2.4 GHz 900 MHz
Frequency bands

2.4 GHz & 900 MHz

ELRS operates on both 2.4 GHz (SX1280) and 900 MHz (SX127x/SX126x) bands. 2.4 GHz excels at speed; 900 MHz punches through obstacles and extends range.

< 1 ms
Latency

Under 1 ms end-to-end

At its fastest packet rates, ELRS achieves sub-1 ms latency — far below the human reaction threshold and well ahead of many proprietary protocols.

500
Hz max rate
<1ms
latency
500 Hzfastest
250 Hzrace / freestyle
150 Hzbalanced
50 Hzlong range
25 Hzmax range
Packet rates

Speed vs range trade-off

Higher packet rates mean lower latency but reduced range. ELRS lets pilots dial in exactly the right balance for their flying style.

frequency hop spread spectrum channel index →
Modulation

FHSS + LoRa / FLRC

ELRS uses frequency-hopping spread spectrum with LoRa for long-range or FLRC for high-speed 2.4 GHz — making the link highly resistant to interference.

100+ km
Range record

100+ km range records

Community members have pushed ELRS to over 100 km in ideal conditions using 900 MHz. Real-world long-range flights regularly exceed 30–50 km.

100+
km record
900
MHz band
Open source

Free, open, and thriving

ELRS is MIT-licensed, with hardware and firmware openly available. Dozens of manufacturers produce compatible hardware.

MIT licensed ESP32 / ESP8285 SX1280 / SX127x EdgeTX / OpenTX Betaflight / iNav Configurator app 50+ hardware options