DJI O4 Air Unit: Fly Light, Shoot Big!

Walksnail has gained ground in the digital FPV market over DJI with its ultra-lightweight systems that 1s batteries can also power. With the launch of the O4 Air Unit Lite, DJI has restored the balance that made its transmission system attractive for micro FPV drones as well.

First, I should clarify that “Lite” is not in the official product name; the FPV community gave it due to its minimalist design and lower performance than the Pro edition.

Weighing 8.2 grams, the O4 Air Unit delivers an impressive 10km range, 4K@60fps onboard recording, and low-latency HD video transmission, making it a game-changer for cinewhoops and lightweight builds. But does it live up to the hype? In this review, we put the DJI O4 Air Unit (Lite) to the test to see if it’s truly the best option for FPV enthusiasts looking for top-tier performance in a minimal form factor.

DJI O4 Air Unit (Lite) review

Disclosure: I received this ultra-light digital FPV kit for a product review collaboration with DJI. However, my review is entirely unbiased and reflects my honest opinions and experiences. Technical specifications and quality may vary according to the manufacturer’s reliability, so I cannot guarantee that you will receive an identical product to the one featured in my article, especially since I received mine from the first production batch.

After publishing my O4 Air Unit Pro review, I contacted DJI to test the Lite edition. Weighing just 8.2 grams, it seemed perfect for an ultra-light build. I saw 50-gram micro-whoops with this kit, which is impressive. It gives you onboard 4K@60fps recording and an outstanding range (up to 10 km).

At a glance

The O4 Lite comes in a palm-sized box with included dipole antenna, flight controller cable, camera mounting frame, mounting screws, and a set of rubber damper balls. The kit comprises a camera and VTX connected with a 5cm coaxial cable. As you can see in the picture below, the VTX is just a PCB without any protective case, with all electronic components exposed. This minimalistic design is uncharacteristic of something that comes from DJI, and it looks more like naked mods made by those focused on reducing the drone’s weight to the maximum. This case-less approach presents a considerable risk of malfunction, as a wire that could touch a component, a drop of water, or even carbon fiber parts can cause a short circuit, as they are current-conductive.

The transmission module measures 30 x 30 x 6mm, and the camera is 13.44×12.36×16.50 mm. The VTX has an M2, 25.5mm x 25.5mm mounting pattern, ensuring compatibility with most micro drone frames. It also allows for direct installation of the O4 Lite on top of the flight controller (25.5mm x 25.5mm FCs) or using a stack adapter for 30.5mm x 30.5mm FCs. Remember to use the included rubber damper balls as a spacer between the FC and the video transmitter. The O4 Lite does not have 20x20mm mounting points like the O4 Pro, commonly used for secondary stacks.

The 23GB flash memory chip, UFL antenna, RF module with a metal cover to avoid interference, FC and camera connectors, and a USB type-C port are on the PCB’s front. The link (bind) button and status LED are on the opposite edge of the connectors. The board has no heat sink to save weight, so it quickly gets hot.

The O4 Lite camera has a minimalistic design with an exposed PCB on the back. The kit includes a mounting bracket that attaches to the frame with four screws and a 16mm spacing between them. The tiny camera module features a 1/2-inch CMOS image sensor with a 117° field view.

Pinout, Wiring to FC, and Powering

To make the upgrade process from the previous Air Unit more straightforward and to provide compatibility with the existing flight controllers, the O4 Lite comes with the same pinout (VCC, GND, RX, TX, GND, SBus) and 3-in-1 cable (Power, FC RX/TX, and Radio) as the older O3.

DJI states that the board can be powered by 1S to 3S batteries (3.7–13.2V), but lithium-ion cells, can go down to 2.4V to 3.0V. If you plan to use such batteries, you will need an external 5V or 12 BEC; otherwise, you risk video feed interruption. The new generation flight controllers, such as the BetaFPV Matrix 1S, have an onboard 5V/3A BEC that allows powering the O4 Lite flawlessly.

O4 Air Unit vs O4 Air Unit Pro: Fly light or long?

The O4 is DJI’s first Air Unit series with two models. While the “Lite” edition, weighing only 8.2 grams, is intended for ultra-light Whoops, the Pro edition is an excellent choice for long-range FPV drones. The O4 Lite is a NEO’s FPV system derivative, and the O4 Pro is based on the Avata 2’s. To be as light as possible, the Lite O4 has no micro-SD slot and only one antenna.

Where to Buy?

DJI O4 Air Unit Series is available to order from DJI and authorized retail partners, with shipping starting on January 9, in the following models:

• The DJI O4 Air Unit (Lite) retails for $109 and includes a camera module, transmission module, 3-in-1 cable, antenna, camera bracket, and mounting accessories.
• DJI O4 Air Unit Pro includes a camera module, transmission module, 3-in-1 cable, and two antennas. It retails for $229.

O4 Air Unit RC & FPV goggles compatibility

If you have the Goggles V2 like me or the even older V1, you will not be compatible with the O4 Air Unit. According to DJI, the O4 series can be used in the following RC & Headset combinations:

• Adaptation Plan 1
  • DJI Goggles 3
  • DJI Goggles N3
  • DJI FPV Remote Controller 3
• Adaptation Plan 2
  • DJI Goggles 2
  • DJI Goggles Integra
  • DJI FPV Remote Controller 2

Of course, you can still fly your DIY FPV drone with an external receiver, such as ExpressLRS, Crossfire, or FrSky.

Compatible frames

As mentioned, the transmission unit has a commonly used mounting pattern that can be installed on most FPV frames. Unfortunately, the camera’s new mounting pattern requires frame modification or a new generation frame that is natively compatible. If you want to 3D print your own TPU mount, I have collected tons of free O4 Air Unit STL files.

Shortly after DJI officially released the O4 Air Unit, reputable FPV manufacturers like iFlight, BetaFPV, DarwinFPV, sub250, and Flywoo announced their RTF drones equipped with this system and compatible frames for DIYers. As the included FC cable is only 5cm long, it is clear that DJI intends the “Lite” O4 for 2″ and smaller builds. Find below a list of compatible FPV frames:

• BetaFPV: Meteor75 Pro O4 and Femto
• DarwinFPV: CineApe20
• Flywoo: Flylens 75\85 HD and Flybee 16\20
• sub250: Nanofly20 and Nimble65 HD
• Happymodel: Mobula7 O4
• Axisflying: Manta 5 SE
• GEPRC: T-Cube18 HD O4

I opted for the DarwinFPV CineApe20, which is ingeniously compatible with the O4 Lite and O4 Pro—you only need to change the TPU mount to use one system or the other. For just $145.99, the kit includes all the electronics, including an ELRS AIO flight controller, motors, and a GPS module. Stay tuned if you need details about this build; my review will be published next week.

Nothing is flawless

The camera has a narrow FOV, suffers from jello, and gyro stabilization also struggles if not soft-mounted correctly. It lacks the D-Log M color profile favored for post-production editing. As the onboard storage lasts less than an hour of recording, you must carry a laptop for longer flight sessions. A GoPro or even a tiny Insta360 GO3S camera produces better video quality, so you can’t so you can’t give up using them for 4K recording.

The O4 AU kit is sold as 1s compatible but can’t be powered directly from the battery. If the battery voltage drops below 3.5-3.7v, the video feed becomes unstable. The VTX’s lack of a heat sink and encapsulation of the electronic parts are also weak points.

The list could be longer, but to keep it short, the O4 Air Unit has some limitations, and hopefully, the V2 will be better. It is still a good choice for its attractive price and compatibility with the DJI ecosystem.

The 1-3S Competition!

I think DJI intended to fill a market gap previously covered only by Walksnail—and they managed it well. The O4 Air Unit is your go-to digital FPV system if your primary concern is range and recording quality. On the other hand, the Avatar HD Mini Lite is more suitable for 1S systems, as you can go down to 3.1V. It also has a wider FOV and is $20 cheaper.

You Can Trust Our Reviews!

Since 2014, FirstQuadcopter has reviewed, thoroughly tested, and rated hundreds of products, including drones, gimbals, power stations, action cameras, 3D printers, video lights, and other high-tech gear to help you make better buying decisions.

We don’t do paid reviews or agree to affiliate links. All products are tested fairly and equally, and if anything changes over time, I will update the written reviews.

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