ExpressLRS Long Range System, Affordable Alternative to Crossfire and R9M

ExpressLRS is an open source long range RC system that focuses on range and latency. It’s also way more cost effective compared to TBS Crossfire and Frsky R9M. If you are looking for a cheaper way to start long range flying and prefer open source, check out ExpressLRS.

Why ExpressLRS?

ExpressLRS offers an affordable long range alternative to the popular TBS Crossfire and Frsky R9M. They even claim to outperform these commercial systems in terms of latency as well as range!

As for now, I can only recommend ExpressLRS to the technical people because the setup is not as user-friendly as Crossfire, but hopefully it will only get better with time.

ExpressLRS Github Page: https://github.com/AlessandroAU/ExpressLRS

ExpressLRS is based on SX127x hardware combined with an ESP8285ESP32 or STM32 for RX and TX respectively. It’s using LoRa modulation, same as ImmersionRC Ghost and Crossfire, that’s why it has noticeably better range than systems that aren’t like TBS Tracer.

It can run at maximum 200Hz update rate, if you prefer range over low latency, you can also drop it down to 100 Hz or even 50 Hz.

TX and RX modules communicate via the standard CRSF serial protocol (Crossfire) for easy use with Betaflight and OpenTX.

Getting Hardware

At the beginning, you had to build your own receiver and transmitter module (yea, not easy), but now you can just buy them off the shelf.

You can build your own receiver and transmitter module from scratch by getting the right components, ordering your PCB and solder those tiny little chips on the board. This is probably the cheapest way, a TX module and receiver costs only $30 and $15-20 respectively to build. See their Github page for more info.

You can also flash the ExpressLRS firmware to existing Frsky R9M hardware. However, the process is irreversible, meaning you can’t flash Frsky firmware back on the hardware. Update: you can now flash Frsky firmware back on R9 hardware if you wish.

The most convenient way is to just buy the receivers (ES915RX) and transmitter module (ES915TX) made by Happymodel. They are inexpensive, designed specifically for the ExpressLRS and already loaded with the firmware, so they are plug and play.

The transmitter module is compatible with almost all modern radios with JR module bay, such as the Radiomaster TX16S, Jumper T12, T16 and T18, Frsky Taranis etc.

Here are the specs of the transmitter module and receiver:

ES915TX Transmitter Module

  • Dimension: 55mm*39mm*13mm(include heat sink)
  • Weight: 23gram (exclude antenna)
  • Antenna connector: SMA
  • VCC input: 5~13v, Recommend 5v~9v
  • RF Frequency Range: 902MHz ~ 928MHz
  • Maximum Output Power: <33dBm(For >27dBm operation, we recommend add a fan for force cooling)

ES915RX Receiver

  • VCC input: 3.7~24v Recommend 5v~12v
  • Operation current: ~100Ma
  • Rx To FC protocol: CSRF
  • RF Frequency Range: 902MHz ~ 928MHz
  • Dimension: 16mm*10mm*3mm
  • Weight: 0.70 gram (exclude antenna)
  • Antenna connector: IPEX4
  • Telemetry output Power: <17dBm

Tiny Receivers

Another cool thing about ExpressLRS is its compatible receivers. Happymodel is making these tiny receivers with built-in antenna (the black tower – that’s the whole antenna) – ELRS PP, EP1 and EP2.

No more antennas hanging out getting chopped by spinning props.

As it’s going to be buried inside the frame, it probably won’t perform as well when it comes to range. But for some people this is the perfect solution if they are looking for the absolute smallest or simplest build. For example Tiny Whoops would absolutely benefit from such ExpressLRS receivers as range is not a priority but size, weight and convenience.

How to Use?

In Model settings, go down to External RF, and select CRSF. That’s it. Of course there is a lot more info on github if you want to master this system.

Telemetry Support

Telemetry is constantly being improved, currently supporting at least 14 types of data, including VBAT, current, downlink/uplink LQ and RSSI.

Telemetry screenshots from IntoFPV user Corrado-c.

Range Testing

ExpressLRS is available on both 2.4GHz and 900MHz so some of the tests here are done on different frequencies. Definitely a ton of potential with ExpressLRS by looking at promising test results like these :)

Max Dist. Freq Pkt Rate TX Power Failsafe at Max Range? Pilot Handle Link to DVR
30Km 900M 50HZ 1W No Snipes https://www.youtube.com/watch?v=SbWvFIpVkto
10Km 2.4G 250HZ 100mW No Snipes https://youtu.be/dJYfWLtXVg8
6Km 900M 100HZ 50mW No Snipes https://youtu.be/kN89mINbmQc?t=58
4.77Km 900M 200HZ 250mW No DaBit https://www.youtube.com/watch?v=k0lY0XwB6Ko
2.28Km 900M 50HZ 10mW No Mike Malagoli https://www.youtube.com/watch?v=qi4OygUAZxA&t=75s

9 thoughts on “ExpressLRS Long Range System, Affordable Alternative to Crossfire and R9M

  1. Aamir

    Hi Oscar, been reading your blog since long. This is my first comment. This expressLRS thing seems too interesting. Is there a way to make a conventional pwm receiver for this system?
    Nad also any 8 or 12 channel support rx?
    Sorry for bieng a noob, but i am not very tech savy.

    Reply
    1. Oscar Post author

      I am not too sure at this point, you might need a SBUS to PWM converter or some sort for now. I am sure manufacturers would produce PWM receivers in the future.

      Reply
  2. Joseph

    Hi Oscar,
    I am running an OPEN TX 2.2.3 with my QX7. Is it possible for me to use the Banggood version of Happymodel ELRS?

    Thamk yoy,

    Reply
  3. James T. Jordan

    I’m a little confused about the R9m firmware upgrade. The R9M is known to be a strictly FRSky module. But once I flash espressLRS to it could it be used in a Radiomaster or a Jumper? Or is this particular path into espressLRS solely for the FRSky ecosystem?

    Reply
  4. Colin Uhrich

    At the current state of things, could one get a Jumper T-Lite, running open TX 2.3.11(or most current build for ExpressLRS), Wire in the ExpressLRS ES915TX(might need that current boost Lite Module or battery) from HappyModel with paired ES915RX. Because I should be able to attach a crossfire module to it, flash it and make it work. It may be ugly but I kind of want the Jumpter T-Lite and Express LRS.

    Reply
    1. Oscar Post author

      Hold off for now if you need the Lite module, I’ve heard rumours that Happymodel is making a JR size as well as a lite size, so you won’t have to do any modifications. Release date might be April, but i cannot confirm.

      Reply
  5. Felipe Holanda

    Great article as always. Your blog is fantastic!

    Happymodel product is a good option, but I think that R9M and R9Slim is a better deal to start in ExpressLRS.
    Almost the same price and a very good hardware with powerfull output option.

    Reply

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