DJI O4 Air Unit Pro — digital FPV beside ELRS
O4 / O4 Pro / O4 Wide — we ordered the Air Unit Pro (heatsink + dual antennas)
Source: dji.com/o4-air-unit
The O4 Pro box had been sitting there a week, and I kept staring at that yellow S.Bus wire. DJI’s manual talks as if the air unit is your radio too. We already have a TX16S + ExpressLRS. So: what are you actually buying when you say “digital FPV” — and what do you leave disconnected on purpose?
We needed picture in the goggles on the UL8. Without replacing the radio stack. So we ordered the DJI O4 Air Unit Pro: camera + air unit, 6S-friendly (7.4–26.4 V), beside ELRS.
What “digital FPV” means here
O4 is video. Full stop. Live feed to DJI goggles (typically Goggles 3 / N3 for us). Recording to microSD. That’s the problem we solve: without digital video you’re flying blind or on analog mush — and we want to see what the craft sees first.
RC stays ELRS receiver. We leave the yellow S.Bus wire on the 3-in-1 cable disconnected. Two RC sources at once is a classic way to ruin an evening.
Specs & downloads: dji.com/o4-air-unit/specs · DJI Downloads.
Why Pro, not the light O4
Standard O4 is lighter (~8 g class). Fine for whoops. We’re hanging a Tattu 6S on an 8-inch frame. Then you want sensor room, a heatsink, dual antennas, and a voltage range that can take the pack directly.
The Pro brings a larger sensor (1/1.3″), higher bitrate/resolution (up to 4K/120 depending on mode/goggles), heatsink and dual antennas. Trade-off: ~32 g with camera. We hesitated — “isn’t that heavy?” — but reliable digital video beats the lightest race setup. For now.
Will we regret those grams later? Maybe. Make this work first.
How we power it (and why via the Y)
Power from the pack via the Y-splitter:
6S pack ── Y-splitter ──► O4 Air Unit Pro VCC/GND
See XT60 connectors and power & capacitors. The Pro accepts 7.4–26.4 V — that fits 6S. A separate BEC works too (≥ 13.5 W), but we keep one pack rail.
Signal beside ArduPilot — where DJI confuses you
DJI’s 3-in-1 cable is documented mainly for Betaflight (MSP DisplayPort / S.Bus). We fly ArduPilot + ELRS:
- Video works standalone: power + antennas + goggles link. No FC required to see.
- RC stays ELRS — leave the yellow S.Bus wire disconnected.
- FC OSD via MSP DisplayPort is optional — later, once a UART is free. See O4 install and fpv.wtf & native OSD (no WTFOS on O4).
Full mount and activation steps: O4 install guide.
EU / NL: set CE-compliant transmission power in the goggles. On 5.8 GHz, CE is lower than FCC. Follow the user manual — Setting Transmission Power and local rules. Boring — until neighbours or regulators disagree.
Mount (short): camera forward. Keep the air unit cool. Antennas clear of carbon/ESC and not against the GPS helical (F9P, H-Flow).
What do the five say?
| Reviewer | Found? | Takeaway | Link |
|---|---|---|---|
| Oscar Liang | yes | Pro vs Lite/O3: larger sensor, D-Log M, dual antennas; the sensible pick for image quality on bigger builds | O4 Pro review |
| Joshua Bardwell | yes | Hands-on Pro review: 4K/100 often the best live+record combo; watch FOV/latency per mode | O4 Pro full review |
| Chris Rosser | yes | Dimensions/mounting + AOS V5 adapters for O4/O4 Pro — relevant because we fly UL8/AOS | O4 vs O3 teardown · AOS mount |
| Painless360 | no product review | No dedicated O4 Pro review; does cover HD DisplayPort OSD on ArduPilot (same path we use later) | HD FPV on ArduPilot |
| UAV Tech | no review found | No O4 Pro review found | — |
Our pick: O4 Air Unit Pro, not the light O4. 6S input, better sensor, dual antennas. RC stays ELRS. Oscar/Bardwell back “Pro = image”; Rosser makes the AOS mount less scary. Painless360 helps later with OSD, not with the purchase.
Manuals
| Document | Local | Official |
|---|---|---|
| User Manual v1.0 | DJI Downloads | |
| Product Information | Same | |
| Release Notes | Same | |
| Specs | — | o4-air-unit/specs |
| Firmware / Assistant | — | DJI Assistant 2 (Consumer) |
Specs (Pro)
| Sensor | 1/1.3″ CMOS · FOV ~155° |
| Video | up to 4K/120 (mode/goggles dependent) |
| Input | 7.4–26.4 V (6S OK) |
| Storage | microSD up to 512 GB + 4 GB internal |
| Weight | ~32 g with camera (± antennas) |
| Link | O4 ecosystem (e.g. Goggles 3 / N3 + RC3) |
Read next
- O4 install — mount, power, activation
- fpv.wtf & native OSD — why not WTFOS; MSP DisplayPort
- XT60 connectors · Tattu 6S
- ExpressLRS explained · ELRS receiver · TX16S
Choice log
| What | DJI O4 Air Unit Pro (camera + air unit) |
| Why | Digital FPV on 6S beside ArduPilot/ELRS — eyes, not a second radio |
| Our pick | Pro over standard O4. RC stays ELRS. S.Bus open. |
Photos