The Aomway C403 Max is a complete 3 GHz–7 GHz 4T4R digital video link kit built for long-range, high-altitude FPV work. It ships as a matched pair — a compact VTX for the airframe and an RBox ground receiver — together with a 2 MP 1/1.8″ camera, two IPEX VTX antennas and two high-gain SMA RBox antennas. The link is split into two independent lines (3–5 GHz and 5–7 GHz), so a single jammer cannot take both down at the same time, while the 4T4R antenna layout holds the link together through hard manoeuvres. Glass-to-glass latency stays at 25 ms at 1080P60.
Key Features
- 3–7 GHz Ultra-Wide Band — 36 frequency points across the full 3–7 GHz span, sitting well above the 8 GHz ceiling of most RF jammers currently in service
- 4T4R Dual-Line Architecture — four transmit and four receive paths over two independent links (3–5 GHz and 5–7 GHz) for redundancy and range
- 1080P60 at 25 ms — glass-to-glass latency of 25 ms with 1080p60 or 720p60 video, 5 MHz channel bandwidth
- Built for High Jumps — stable link during high-altitude, high-descent-rate and long-dive flight profiles
- Complete Kit — VTX, RBox ground receiver, camera, two IPEX VTX antennas and two SMA RBox antennas in one box
- 1 TB Onboard Recording — TF card slot on both VTX and RBox, up to 1 TB capacity
- Native Betaflight & INAV OSD — MSP OSD in canvas mode out of the box, no extra OSD board required
- Field-Upgradable — VTX and RBox firmware updated independently from a TF card, and the wireless pairing survives the upgrade
Technical Specifications
VTX
| Parameter | Specification |
|---|---|
| Model | C403 Max |
| Communication Frequency | 3–7 GHz |
| Communication Bandwidth | 5 MHz |
| Transmit Power (EIRP) | MAX 33 dBm; FCC <30 dBm; CE <14 dBm; SRRC <20 dBm; MIC <25 dBm |
| Frequency Points | 36 |
| Power Input | 11.1–40 V |
| Interfaces | JST 1.0 4-pin power cable, TF card slot |
| SD Card Slot | Up to 1 TB |
| Video Resolution | 1080p60fps / 720p60fps |
| Mounting Hole Spacing | 25.5 × 25.5 mm |
| Dimensions | 34 × 34 × 18 mm |
| Weight | 22.41 g |
| Operating Temperature | −20 to 60 °C |
| Flight Controller Support | Betaflight, INAV |
| OSD | Canvas mode |
| Antennas | 4 × IPEX — the VTX uses 2 antennas, each with 2 IPEX connectors; one antenna covers 3–5 GHz, the other covers 5–7 GHz |
RBox (Ground Receiver)
| Parameter | Specification |
|---|---|
| Model | C403 Max |
| Communication Frequency | 3–7 GHz |
| Communication Bandwidth | 5 MHz |
| SD Card Slot | Up to 1 TB |
| Type-C Interfaces | 3 × — USB-A to Type-C to PC for software upgrade; USB 3.2 Type-C to Type-C to display for DP output; UART EXP serial port at TTL 3.3 V |
| Power Input | 9–30 V, 2 A |
| Fan Interface | Provides 5 V / 200 mA supply |
| Button Interface | Connects to the factory-matched keypad; custom keypads can be developed independently |
Camera
| Parameter | Specification |
|---|---|
| Image Sensor | 1/1.8 inch, 2 MP |
| Resolution | 1080p60fps / 720p60fps |
| Aspect Ratio | 16:9 / 4:3 |
| FOV | 160° |
| Aperture | F1.8 |
| Shutter | Rolling shutter |
| Minimum Illumination | 0.0001 Lux |
| Dimensions | 19 × 19 × 24 mm |
| Weight | 13.47 g |
| Coaxial Cable Length | 140 mm |
Antennas
| Parameter | VTX Antenna | RBox Antenna |
|---|---|---|
| Polarization | LHCP | LHCP |
| Bandwidth | 3–5 GHz / 5–7 GHz | 3–5 GHz / 5–7 GHz |
| Average Gain | 2 dBi | 10 dBi |
| Input Impedance | 50 Ω | 50 Ω |
| VSWR | <1.5 | ≤2.5 |
| Interface | IPEX-1 | SMA-J |
| Weight | 9.78 g and 10.08 g | 165 g and 95 g |
Interfaces & Wiring
The VTX exposes five interfaces. Always connect both antennas before powering on — running the transmitter without a load can damage the RF stage.
- Power (JST 1.0 4-pin) — VIN, GND, RX2 and TX2. RX2/TX2 are the flight-controller UART pair, 3.3 V level, referenced to the VTX
- Visible camera — MIPI 2-lane or 4-lane
- Debug — RX0 / TX0 / VBUS / GND / DP / DM, intended for the factory debug sub-board only
- Infrared camera — MIPI 1-lane or DVP
- Frequency pairing button — short press to enter pairing
On the RBox, the three Type-C ports handle PC firmware upgrade, DP video output to a display, and a TTL serial link for the ground station. The green keypad shipped with the unit is required to navigate the on-screen menu.
Pairing & Firmware Upgrade
Pairing: power both units, short-press the pairing button on the VTX and on the RBox. Both dual-colour LEDs flash rapidly and the buzzer emits short beeps. When the link is established the RBox buzzer sounds one long beep and both green LEDs stay on.
Upgrade: copy the VTX and RBox firmware to the root of the TF card using the exact names A1_SKY_v1.x.x_xxxxxxxx.img and A1_GND_v1.x.x_xxxxxxxx.img, insert the card into the RBox, then choose Settings → System → System Upgrade. Whichever firmware is present gets upgraded; the other device is left untouched, and the wireless pairing is preserved after reboot. Current version is shown under Settings → System → About.
Flight Controller Setup
Betaflight: solder the white and grey wires of the 4-pin cable to a spare UART, open the Betaflight Configurator, and set that port as the MSP display port (UART2 in the reference setup). Save and reboot. The OSD font currently supports the HD video format.
INAV: wire the same pair to a spare UART, connect with the INAV Configurator, and set the port as MSP display (UART4 in the reference setup). Save and reboot. The INAV OSD font currently supports the HDZERO video format.
Recommended Accessories
- Aomway 3.3G RHCP 4dBi Antenna — low-band extension for the 3–5 GHz line
- Aomway 7G–8.7G RHCP 4dBi Antenna — omni coverage on the high band
- Aomway 7G–9G RHCP 13dBi Patch Antenna — directional gain for long-range ground station work
- Aomway Commander V2 FPV Goggles — ground viewing with the RBox DP output
Ready to fly farther? The C403 Max 3–7 GHz 4T4R link is available from Aomway with custom frequency and enclosure options. Tell us your airframe, range target and antenna budget, and we will configure the kit for you — info@aomway.com.
Aomway has been developing and manufacturing video transmission equipment for 15 years, accumulating extensive industry experience and massive test data. We can produce video transmission devices for any frequency band from 1 to 9 GHz, with power ranging from 3W to 15W. No development fees and free samples available. For inquiries, contact us at info@aomway.com.
