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ExpressLRS 2.4 vs Crossfire and TBS Tracer: range and penetration

ExpressLRS vs Crossfire and Tracer: range and penetration
ExpressLRS vs Crossfire and Tracer: range and penetration

Which is the best: Crossfire, TBS Tracer, or ExpressLRS 2.4?  Here’s a comparison of the three receivers for range.  There’s also a comparison between ELRS and Crossfire for penetration.

Background

There are dozens of types of receivers for FPV drones, such as FrSky, Crossfire, and DJI — each with their own advantages and disadvantages, and each one incompatible with the others.   Is it possible that the industry will converge on one standard?  Having a single standard would help in a lot of ways: radios, antennas, flight controllers, and accessories could all be designed around a universal standard.  Express LRS is an open source protocol that is rapidly becoming a strong candidate as the single best receiver protocol not just for a particular use, but for potentially all types of FPV.  Its advocates claim that it has the best range, the best penetration, one of the lowest latencies, has one of the lowest cost equipment, and is open source.

ExpressLRS also has cutting edge features such as wireless firmware update and easier binding than some popular receiver protocols.  Another benefit is that it has a small but strong community that is committed to helping ExpressLRS users.

Despite its technical advantages, ExpressLRS had been considered more complicated and less accessible.  However, you can now buy ExpressLRS transmitter modules for JR module bays and nano module bays that are available on many radios.   And there are now a few preassembled BNF (bind and fly) quads with built-in Express LRS receivers from Happymodel, Flywoo, and BetaFPV.  (It’s widely expected that other manufacturers will soon follow.)

But is Express LRS good enough to beat Crossfire or TBS Tracer, which are widely considered to be among the best, if not the best receivers?

Part 1: Range

Here is a range comparison by FPV drone gear reviewer Gal Kremer.   For these tests, Gal mounted two receivers on a test box with a flight controller and VTX.  He mounted the box on a Mavic and flew the Mavic while observing the signal of the receivers.  If you want to find out more, here is a video showing the test procedure that Gal Kremer used.

On to the range comparison. First, here is a comparison between ExpressLRS 2.4 vs TBS Tracer.  This is an interesting test because they both use 2.4 ghz frequency:

The ELRS receiver here was the version with a compact ceramic antenna, which has about half the range of the version with conventional antennas.  Despite that handicap, and despite the fact that the ELRS was on 500hz sampling rate while the Tracer was on 250hz, ELRS had more than twice the range of TBS Tracer, with both set to 25mw.  TBS Tracer failsafed at around 1.7km, while ELRS failsafed at around 4km:

ExpressLRS vs TBS Crossfire. Left: TBS Crossfire failsafe at 1.7km at 25mw. ELRS 2.4 failsafe at 4km at 25mw.
ExpressLRS vs TBS Crossfire. Left: TBS Crossfire failsafe at 1.7km at 25mw. ELRS 2.4 failsafe at 4km at 25mw.

What about Crossfire?  Crossfire uses 900mhz frequency (915mhz or 868mhz, depending on the region), which in theory should have longer range than the Express LRS 2.4.  Gal Kremer tested the signal strength at 3km, with both set to 25mw.  Here’s the comparison:

When both are set to 25mw, at 3km, ExpressLRS has a stronger signal than Crossfire (negative 89db vs. negative 97db, respectively).

Left: ExpressLRS at -89db and Crossfire at -97db
Left: ExpressLRS at -89db and Crossfire at -97db

Part 2: What about penetration?

The tests above had little or no obstructions.  How do they compare for penetration?  In theory, the 900mhz system should have better penetration.  The following is a test by DustyPropsFPV, where he compared ELRS 2.4 with Crossfire at a garage.  DustyProps used the ExpressLRS EP2 receiver with the ceramic antenna (which again has about half the range of an ExpressLRS EP1 receiver with antenna) and compared it with Crossfire, both at 25mw.

In this test, DustyProps found that Crossfire failsafed before the ELRS failsafed, which, if true, implies that at the same signal strength, ELRS has better penetration (or can get a working signal with much less data).

Conclusion

These tests seem to show that ExpressLRS 2.4 has better range and better penetration (or more precisely, is better ability to continue functioning in spite of obstructions) than Crossfire at the same power of 25mw, which is surprising and should be tested further to confirm.  Meanwhile, my cinewhoops already have Crossfire and I have a Crossfire Micro TX v2 module (with up to 1 watt power), which have performed very well for me so I’m not inclined to replace it.  However, I plan to experiment with converting my other quads that have Frsky XM+ or DJI receiver into ELRS 2.4.  In any case, if ExpressLRS does become the de facto standard receiver for FPV, that would be great for the industry.