ExpressLRS is one of the most exciting control links today. It is open source, which means enthusiasts develop it for free, just because they love doing it. Their goal was to develop the lowest-latency control link possible. A side effect of a super low latency link is that range is reduced. But happily, ELRS lets you decide: do you want a super low latency, shorter-range link; or do you want a higher latency, ultra long range link. This means that ELRS can basically meet the needs of any pilot: from a racer who wants 500 Hz refresh rate, to a long-range enthusiast who wants to fly 60 km or more.
Despite its amazing performance, there are a few reasons why some people will skip ELRS. The first one is that commercial ELRS hardware may not be made to the same standards as TBS or Ghost receivers. Many different manufacturers make ELRS compatible receivers, and some have higher quality standards than others. With Crossfire or Ghost, there is a single company that cares about the reputation of the system and the quality of the hardware. With ELRS, that’s not as true. (If you really think you can do it better, you can still buy a kit and solder up your own ELRS hardware.)
A second drawback of ELRS is that it’s a little more complicated to manage than some other systems. Owning an ELRS system, you are expected to be able to compile your own firmware and flash it to your module and receivers. There’s a PC-based utility that makes this as easy as possible, but it’s still more difficult for most novices than Crossfire and Ghost.
A final drawback is that ELRS is designed to be used with a flight controller. If you fly planes with servos driven directly off the receiver, ELRS doesn’t work well for that. However, this is changing fast! As of this writing, Matek has released the first ELRS receiver with PWM outputs! Even still, ERLS only delivers full resolution on the four main control channels. All aux channels have a resolution of at most 128 positions. That might be fine for flaps, but it wouldn’t work anywhere you need very precise control of a servo position.
ExpressLRS hardware comes in two versions: one for 900 MHz operation and one for 2.4 GHz operation. Most experts agree that 900 MHz is only necessary for those looking to go extremely long ranges–like 50 km or more. Although 2.4 GHz has a reputation for poor range and penetration, the LoRa technology used by ELRS more than makes up for this. 2.4 GHz is a universal worldwide band; can have more pilots in the air without interference; has smaller antennas; and can operate up to 500 Hz or more. All of the equipment on this page is 2.4 GHz ELRS for this reason.