The DJI Digital FPV System consists of: Air Unit, FPV Goggles and the optional DJI radio controller. I will skip all the specs and basic stuff which you can look up on the manual, and get straight into the user experience side of things.
The Air Unit consists of a camera and a video transmitter. This mounts in your racing drone just like an analogue FPV camera and VTX. The entire casing of the Air Unit is made of aluminium, which doubles as protection, and a heatsink for cooling. The Air Unit including camera and antennas weighs around 53g.
The DJI camera, like most micro FPV cameras, has M2 mounting holes on both sides, but with 20x20mm form factor, is a bit bigger than the typical 19x19mm (micro FPV cam). It has a 150° field of view (FOV), similar to an analogue FPV camera with 2.1mm – 2.3mm lens.
The VTX is considerably bulkier than its analogue counterpart, making it a challenge to find a racing drone frame with enough space. (update Jan 2020: The good news is that there are already many frames available that are designed for the DJI Air Unit, so space is not an issue anymore). The cable between the VTX and camera is about 100mm, which should be long enough for most 5″ builds, even when you are mounting the video transmitter in the back.
The Air Unit has two antennas with MMCX connectors: a JST connector for power, UART connection to flight controller, and radio control signal (if you use their radio controller). A nice touch are the cable grommets offering stress relief to the connection between the camera and air unit.
Like the Runcam Split, there is an SD card slot on the side of the Air Unit, for recording HD video up to 1080p 60fps, but obviously DJI have added HD FPV to the recipe. You don’t get 2.7K or 4K resolutions with the recorded footage like the GoPro, but it’s good enough for most people.
There are 3 modes for different situations:
- Standard Mode offers the best daytime image quality, probably what you would use for freestyle flying
- Racing Mode increases image contrast to distinguish brightly coloured obstacles better
- LED Mode increases visibility on LED light, best for night flying
The power consumption of the Air Unit is about 4W to 8W according to DJI, at 12V, the current is 333mA to 666mA. If you power it with a 4S LiPo (14.8V), that would be 270-540mA.
Here are flight controllers designed specifically for the DJI Air Unit, making it a solder-free, plug and play combo.
The DJI FPV goggles come with four left-hand circular polarized (LHCP), omni-directional, ‘stubby’ antennas, mounted using RP-SMA connectors. These can be removed for transportation, as well as replaced and upgraded.
From my understanding, the top two antennas are responsible for transmitting and receiving signals. Unlike an analogue FPV system, the DJI goggles have a transmitter inside which means that they can be damaged if they are powered on, without the antennas attached. The top 2 antennas send data, as well as receiving in conjunction with the bottom 2 antennas, for a “quad-versity” receiver system.
There are already after-market antennas available for the DJI FPV goggles, with higher gain for better range and penetration: http://bit.ly/35kWQ0E
The DJI goggles have the following features:
- built-in anti-fog / cooling fan
- built-in DVR – 720p 120FPS
- IPD adjustable
- Firmware update via USB-C port
- Supports Audio play back on videos from Air Unit, but doesn’t support audio with live video feed or recorded video in the goggles
- When changing channels on the FPV goggles, it automatically changes it on the Air Unit too
The goggles are powered by an external battery via a cable which has an XT60 connector, so you can power it with a 2S LiPo battery like a Fatshark.
It’s heavier than most other compact design FPV goggles, even without a built-in battery. The ample weight is distributed effectively by the well designed strap, while face-plate foam of the highest quality ensures a comfortable fit. Faceplate foam has better quality than any FPV goggles I have tested.
The field of view (FOV) is larger than most slimline goggles, but racers often prefer a smaller FOV to allow for tighter focus on the course. DJI have addressed this in a novel way, providing the ability to zoom in on the image, but the OSD info will remain at the corners of the screen.
The goggles are quite power hungry, and don’t last long using a typical Fatshark battery. A 2S 3000mah only lasts for about an hour. You can use a larger battery, but you’ll need a long cable to keep the battery in your pocket or on the ground.
DJI offers their own radio controller, with the benefit that you won’t need a separate radio receiver in your drone, because the Air Unit has one integrated. But you don’t have to get DJI’s radio if you plan to use your own.
The Radio might not look like anything popular on the FPV market, but the ergonomics are actually pretty good. The gimbals are on par with the Hall sensor gimbals from Frsky, if not better.
Why You should Get DJI FPV System?
Glorious FPV Feed
This is the biggest selling point.
The first reaction from everyone who tries this system is “WOW! Amazing!”. There is no breakup or static like analogue system. It’s almost like flying FPV with GoPro quality video. Perhaps an exaggeration, it’s more like the Runcam Split quality when looking through the goggles, but still it’s exceptional.
The video feed in ideal conditions sends 720p 120fps to the goggles, so what you see is extremely smooth and high detail video. In comparison, analogue video is around 360p at 25fps (maybe even worse with some cheaper cameras).
The DJI camera also has excellent dynamic range and low light performance, nearly as good as some of the expensive analogue cameras, like the Runcam Micro Eagle.
Unlike other HD FPV systems, which suddenly stutter and freeze when the signal weakens, the DJI system combats this by gradually reducing the resolution of the image. It will eventually begin to stutter when signal gets very weak, but the experience isn’t so intrusive and distracting.
The OSD (on screen display) is great, it shows all the important telemetry data and settings. For example it tells you the camera settings like White Balance, Exposure, Saturation, VTX Channel, Drone Battery Voltage, Signal strength, and DVR recording status.
The first concern of HD FPV systems is latency. Details from the manufacturer say latency from radio to the drone is about 7ms while the drone to the FPV goggles is 23ms, which is similar to that of the analogue FPV system. Without interference there is no discernible latency, so I would say it’s just as good as analogue in that regard.
There are two modes that affect quality and latency: High quality mode that sends higher resolution footage in 60FPS, and low latency mode that sends lower resolution footage in 120FPS.
There is also a great feature called Focus Mode, which reduces latency by reducing the bit rate around the edges of the image, while keeping the centre as clear as possible to minimize distraction to the pilot.
HD Video Recording
The recorded video in the goggles is 720p 120FPS, while on the Air Unit, it’s 1080p 60FPS. It certainly can’t compete with the GoPro, but it looks way better than analogue DVR for sure, and even better than some low cost HD cameras.
The audio quality is mediocre, maybe between Runcam Split and GoPro quality.
The DJI Digital FPV system probably won’t replace the GoPro for some people, because it doesn’t do 4K or even 2.7K yet, and it doesn’t have “superview” and flat color option.
Advertised range is 4Km, around 2.5 miles. That’s pretty good compared to analogue systems, but in Europe the output power is restricted to 25mW (CE mode), resulting in lower range of around 700m. It’s possible to “unlock” the VTX and use the full power of 700mW, but you would be breaking the law doing so…
Based on my experience, comparing to analogue system on similar output power, the DJI FPV system definitely edges out in terms of range. The DJI FPV system performs much better too in environment with multipathing interference.
Although DJI is not known to integrate with 3rd party systems, they have worked with BetaFlight to incorporate the full BetaFlight OSD into their HD video feed. This OSD compatibility is currently exclusive to BetaFlight, and we have no idea if it will ever support other flight controller firmware in the future.
Cost – Not That Bad Actually
The DJI FPV system might sound expensive, but if you think about it, it really isn’t that bad. In fact, it’s actually slightly cheaper than the most expensive analogue system you can buy:
- HDO2 – $500
- Rapidfire Receiver Module – $150
- Decent antennas – $50
- Runcam Eagle FPV Camera – $45
- TBS Unify Pro VTX – $50
That’s $800 – the same price as the full DJI system including the transmitter! Don’t forget you can use the DJI system as your HD camera as well, so add that to the equation, and you might find the DJI system a really good deal.
If you are new and buying everything today, the DJI digital FPV system can be a more cost effective solution (assuming it meets all your needs). For sure, if you already own an analogue system then it is pricey to re-buy, but if you are thinking of upgrading to a top of the line pair of goggles, this might make your decision a little more difficult.
The Goggle Is Actually Good!
The DJI Goggles optics are actually very good, especially the super wide FOV that they offer. It might appear to be similar to the size of box goggles, but it’s smaller in real life.
Although I still prefer the image quality from the OLED goggles, like the HDO2 and SKY03O (the color is just more vibrant with higher contrast), in terms of non-OLED goggles, I’d say the DJI goggles are probably one of the best.
The Negatives of DJI FPV System
Concerns with Interference and Lost Signal
Like all other HD systems, the common downside is how they handle weak signal. Many people still prefer analogue for FPV, because when the signal gets weak, the feed might become snowy, but you can still roughly see where you are going.
it’s true that the DJI system handles weak signal better than many other HD systems, but it can still stutter and freeze from extended range or outside interference. Additionally, If you use their radio, you can also lose control, because the radio uses the same 5.8GHz link. Not only it’s hard to fly out of that, it can even be dangerous, so I’d be more cautious when flying with a group.
If you want to fly long range, or in environment with many obstacles, maybe the DJI FPV system is not the best option at its current form. However this is a great system if you mostly fly over open field and don’t need much object penetration.
Air Unit Limitations – Size & Voltage
The air unit is quite bulky, as big as another 30x30mm FC + ESC stack, so it doesn’t fit every frame. You may have to get a frame specifically for the DJI Air Unit, but there is an FC stack designed for it, to avoid a complicated setup. For that you are looking at potential additional costs.
The air unit only supports 4S, so you might need a voltage regulator if you run 6S. According to my contact, when they started developing this product, everyone was still only flying 4S. 6S wasn’t even a thing back then, too late for them to change the hardware now.
Although latency is generally not an issue, it does change with signal quality. That means with range, obstacles and interference, the latency will go up as signal strength decreases. This will impact your ability to control the aircraft precisely – particularly at high speeds. That’s why I don’t recommend flying the DJI system for long range or at places with heavy interference.
The temperature of the Air Unit can also have an effect on latency, video quality, and range, it also gets hot from use. You need to be flying, and ensure adequate airflow around the VTX to keep it cool for it to perform optimally.
It’s a proprietary system, so it is sadly not cross compatible – How I wish we could use our own goggles! The ability to display the FPV image on the popular Fatshark HDO2, Skyzone SKY03O or the Orqa FPV.One, would make this DJI offering far more tempting for many who have already invested in HD goggles. Frankly these companies have more experience, and they make goggles that fit better.
FPV Goggle Great but Not Perfect
The goggles overall are very well made, very comfortable to wear, and they are big enough so you can just put them on, no need to fuss around to get the screen aligned with your eyes.
Still, DJI need to do a bit more work here and there to make it perfect, i.e. the fit is not optimized, there are light leaks, and the nose presses down uncomfortably for some people. It would definitely help if there were different faceplate and foam pad options.
The power barrel connector doesn’t seem to fully engage and is likely to come loose if you tug it accidentally. You could use a zip tie to attach the cable to the head strap and eliminate the problem, but it would have been nice if the design had considered this.
DJI are still relatively new to FPV goggles and will, no doubt, improve future releases. With that said, this really is a very good first attempt.
It Won’t Replace Analogue, Yet
The variable latency just means it’s not quite ready for racing yet, I’d imagine most racers would still prefer the good old analogue for the more consistent and predictable performance. The HD feed would be useful in big live events, but people won’t be able to watch, unless they are also using DJI goggles.
I don’t think it will completely replace analogue, at least not for a while. So you can breathe a sigh of relief, your analogue setup isn’t completely outdated… yet! The Air Unit is also too heavy for micro quads, anything smaller than a 3″ will have trouble carrying it.
There is a workaround to use the AV input connected to a ground station to receive analog signal, but it would have been great if the DJI goggles had an integrated analogue receiver, or supported VRX modules.