Long Range seems to be coming back into vogue these days with some 5inch and smaller quads now claiming 20 to 30minute flight times.
It used to be that if you wanted long range you’d use one of the UHF systems: EzUHF, Dragonlink, OpenLRS, etc. About four years ago TBS released their Crossfire system, 868MHz/915MHz, which was more suited to five inch quads as the receivers and antennas are much smaller than the 433MHz stuff.
In the last few months ImmersionRC started touting their Ghost system which uses LoRa technology on 2.4GHz, with tiny receivers and tiny efficient antennas, but I’ve been seeing reports of non-recoverable failsafes, not good if you’re flying a mission as even if the model returns under GPS control you won’t be able to retake control but rather wait for the battery to deplete and the model to glide/fall back to Earth.
In the last few weeks TBS have announced their 2.4GHz Tracer system, and it’s available to buy in the UK, which the Ghost system isn’t yet. On top of that it’s fully integrated into OpenTX using standard CRSF Lua scripts, something else which Ghost isn’t. It can also be used with the Tango controllers using an optional connector for the module bay. Trappy isn’t touting it as a long range system but rather as a very low latency (4ms) race/freestyle system, however he has said they have tested out to 50km.
I think the Tracer module is selling for about £69 and the receivers are about £26. There is a bundle deal incorporating the module, three receivers, and six dipole antennas (the receivers are diversity receivers) for about £129.
So will current Crossfire users be switching from 868MHz/915MHz, with only 1MHz bandwidth and floppy antennas, to the 2.4GHz Tracer with its 60MHz of bandwidth and smaller antennas more suited for those smaller builds?
From a RF and quad point of view if the Tracer system holds up to Trappy’s claims it’s a win-win solution for those wanting long range and even those just wanting a strong reliable connection in an RF congested environment such as those found at large racing and freestyle events.
It does look good. Especially for 3" (antenna size) but 868 will still have better penetration behind obstacles at distance. Basic law of physics. If you intend to fly behind wet trees 1 or 2 km out!
Yes and no. I have a few 868MHz/915MHz systems that transmit into similar antennas and power levels as those used by Crossfire owners but I don’t get the range of Crossfire, or even that of my FrSky ACCST receivers on 2.4 GHz. The modulation, protocol, and error correction, has an awful lot to do with that. Crossfire uses LoRa which in basic terms allows the signal to be received even when the signal to noise ratio is very low and where more conventional techniques would failsafe in the same noisy environments. That’s why in some situations you can still have a good link quality with Crossfire even if the signal strength is pants, and why many guys in my club using Spektrum DSM2 keep having unscheduled landings.
Having now switched to CRSF I’ll probably stay on that. If I were to try something different it would be the Tracer system to keep within the TBS ecosystem which just seems to integrate better. At the moment though it’s the range of the DJI HD system which is now the limiting factor in terms of longer range (for which I’m looking at using helical antennas, but that’s a whole different discussion).
I have just bought the Tracer system for exactly that reason as wanted to try Long Range and also invested in a 7" long range and moving to DJI for that too. I can update you on how it flies once Santa has landed!
I would certainly be interested in hearing your experiences with the Tracer system. I’m still flipping between whether to invest in the Tracer or wait for the Ghost system to go on general sale. My interest in these systems is for 3inch and smaller.
Currently I’m using EZUHF for long range on my larger quads and some endurance fixed wing models. I chose this over the very capable Crossfire system as I can legally operate on 433MHz at higher power levels than the 100mw ISM standard under the schedule of my amateur radio license. For clarification this is only permitted when transmitting from the ground to an airborne model. The UK amateur license does not permit the use of high power transmitters on an airborne model unlike in the USA and other regions. This is a very big shame as there are amateur radio allocations in both the 1.3GHz, 2.4GHz, and 5.8GHz ISM bands which, if the law was changed, would legally allow higher power video transmitters. It would also entice some much very needed new technical blood into amateur radio. I questioned both the RSGB (radio equivalent of the BMFA) and OFCOM if there was a possibility of amending the current schedule to allow for higher power experimentation with airborne models and unfortunately the silence was deafening. It’s one of the many reasons why, after being licensed for nearly 40 yrs, I chose to relinquish my membership of the RSGB and mothball my amateur radio gear…
I’m sorry, I went into unsolicited waffle mode again.