VT5805 5.8 GHz 4W Video Transmitter — User Manual
The VT5805 is a high-power 5.8 GHz analog video transmitter (VTX) module with selectable output up to 4 W (4000 mW) — the long-range flagship of the series. It transmits a standard CVBS analog video signal on any of 48 channels across 6 bands, is remotely configurable over TBS SmartAudio, and pairs a machined heatsink case with a built-in cooling fan to sustain full power. A wide 7–36 V input (2S–8S) and a regulated 5 V camera output make it a complete video link for long-range fixed-wing, mapping, and industrial platforms.
Where to buy
Available from Robofusion: robofusion.net
An FPV (First-Person View) video link has three parts: a camera on the aircraft produces an analog video signal (CVBS — the classic composite format), a video transmitter (VTX) like the VT5805 broadcasts it over the air at 5.8 GHz, and a receiver in your goggles or ground station picks it up. Analog video has near-zero latency and degrades gracefully at the edge of range instead of freezing — which is why high-power analog links like this one are still the tool of choice for genuine long-range work. Transmit power (mW) is the main range lever: 4 W reaches many times farther than a typical 25–800 mW racing VTX, at the cost of current draw and heat.
VT5805 or VT5804 — which one?
The VT5805 and VT5804 are the same platform at two power classes:
| VT5805 | VT5804 | |
|---|---|---|
| Max output power | 4 W (25/1000/2000/4000 mW) | 2.5 W (25/600/1200/2500 mW) |
| Cooling | Heatsink case + built-in fan | Finned heatsink case |
| Height / weight | 13.5 mm / 16.9 g | 7.2 mm / 11 g |
| Max current | 1100 mA @ 12 V | 850 mA @ 12 V |
| Best for | Maximum range, larger airframes | Weight-sensitive builds, medium-long range |
Everything else — bands, channels, wiring, SmartAudio, mounting pattern — is identical.
Specifications
| Item | Specification |
|---|---|
| Product name | VT5805 video transmitter module |
| Frequency band | 5.8 GHz (5362–5945 MHz, 48 channels / 6 bands) |
| Transmit power | 25 / 1000 / 2000 / 4000 mW (4 levels) |
| Video format | CVBS (analog composite) input |
| Input voltage | 7–36 V (2S–8S) |
| Max current | 1100 mA @ 12 V |
| Camera power output | 5 V regulated |
| Cooling | Aluminum heatsink + built-in fan |
| Configuration protocol | TBS SmartAudio |
| Antenna connector | MMCX |
| Dimensions | 38 × 36.5 × 13.5 mm |
| Mounting hole pattern | 30.5 × 30.5 mm |
| Net weight | 16.9 g (excluding antenna) |
What's in the box
- 1 × VT5805 transmitter module
- 1 × 6-pin ribbon cable
- 1 × MMCX-to-RPSMA extension feeder cable
- 1 × product manual
The VT5805 ships with an RPSMA extension feeder but no antenna. At 4 W, antenna quality matters — pair it with a well-matched 5.8 GHz antenna rated for high power (a quality linear or pagoda/patch setup depending on your application).
Wiring
The VT5805 uses a single 6-pin connector. Pin 1 is marked on the case:
| Pin | Function |
|---|---|
| 1 | VIN — 7–36 V power input (DC IN) |
| 2 | GND — power input ground |
| 3 | RX_OSD — TBS SmartAudio (flight-controller configuration) |
| 4 | VOUT — 5 V power output (for the camera) |
| 5 | GND — power output ground |
| 6 | VIDEO — CVBS video signal input |
Typical hookup: battery (or PDB) → VIN/GND; camera video out → VIDEO; camera power → VOUT/GND (pin 4/5); flight-controller UART TX → RX_OSD if you want SmartAudio control.
Powering a 4 W VTX without an antenna attached reflects the RF energy back into the output stage and can permanently destroy the module within seconds. Always attach an antenna (directly or via the RPSMA extension) before connecting power. No exceptions — not even "just for a moment".
Even with the built-in fan, a 4 W transmitter runs hot. Keep the fan intake unobstructed, leave air space around the heatsink fins, and never wrap the module. On the bench, configure at 25 mW and keep full-power runs short unless the aircraft is moving air over it.
Bands, channels, and frequency table
The VT5805 covers 48 channels: 6 bands (groups) × 8 channels. Frequencies in MHz:
| Band | GR LED flashes | CH1 | CH2 | CH3 | CH4 | CH5 | CH6 | CH7 | CH8 |
|---|---|---|---|---|---|---|---|---|---|
| A | 1 | 5865 | 5845 | 5825 | 5805 | 5785 | 5765 | 5745 | 5725 |
| B | 2 | 5733 | 5752 | 5771 | 5790 | 5809 | 5828 | 5847 | 5866 |
| E | 3 | 5705 | 5685 | 5665 | 5645 | 5885 | 5905 | 5925 | 5945 |
| FS/IRC | 4 | 5740 | 5760 | 5780 | 5800 | 5820 | 5840 | 5860 | 5880 |
| RACE | 5 | 5658 | 5695 | 5732 | 5769 | 5806 | 5843 | 5880 | 5917 |
| LOW | 6 | 5621 | 5584 | 5547 | 5510 | 5473 | 5436 | 5399 | 5362 |
This is the standard analog 5.8 GHz grid, so any analog goggles or receiver can tune to the VT5805 — just set both ends to the same band and channel. RACE (Raceband) spaces channels 37 MHz apart to reduce cross-talk between pilots; FS/IRC is the FatShark/ImmersionRC band. At 4 W your signal will dominate a wide area — check that no one nearby is flying on an adjacent channel before powering up.
LED indicators
Five LEDs show the current configuration at a glance:
| LED | Meaning |
|---|---|
| P | RF power indicator |
| C3 / C2 / C1 | Channel indicators (binary combination) |
| GR | Group (band) indicator — number of blue flashes = band |
Channel readout — O = LED on, X = LED off (C3 C2 C1):
| Channel | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|
| C3 C2 C1 | X X X | X X O | X O X | X O O | O X X | O X O | O O X | O O O |
The blue GR LED's flash count indicates the band (1 flash = A … 6 flashes = LOW), and the green C1–C3 LEDs indicate the channel per the table above.
Button configuration
All settings can be changed with the single button on the side of the case:
| Action | What it does |
|---|---|
| Short press | Cycle through channels 1–8 |
| Hold 3 s (blue LED flashes, then release) | Enter band selection — short presses cycle A → LOW |
| Hold 6 s (blue LED turns off, red lights, then release) | Enter power selection — short presses cycle 25 / 1000 / 2000 / 4000 mW; green flash count (1–4) shows the level |
| Hold 2 s (inside a selection mode) | Save and exit |
After changing band or power, always finish with the 2-second hold to save — otherwise the change is not stored.
SmartAudio — configure from your flight controller
Pin 3 (RX_OSD) speaks TBS SmartAudio, the de-facto standard for VTX remote control. Wire it to a spare UART TX pad on your flight controller and you can change band, channel, and power from your radio or OSD menu instead of the button:
- Betaflight / iNav: assign the UART to VTX (SmartAudio) in the Ports tab, then use the OSD or Vtx Tables.
- ArduPilot: set
VTX_ENABLE=1and the relevantSERIALn_PROTOCOL=37(SmartAudio), then control power/channel via parameters or the transmitter.
With SmartAudio you can arm-switch between 25 mW on the bench and 4 W in the air. That protects the module from overheating on the ground, keeps you legal at the field, and spares every other pilot's video feed within a kilometer.
Transmit power and the law
4 W is far above the unlicensed limit in most jurisdictions. In the US, operating above 25 mW on these frequencies effectively requires an amateur (HAM) radio license, and 4 W operation should follow your license privileges; Canada and Europe have similar or stricter rules. Use 25 mW indoors, at races, and around other pilots — reserve the high-power levels for licensed long-range operations in open areas. You are responsible for complying with local regulations.
FAQ
No video in my goggles — first checks?
Antenna attached, VTX and receiver on the same band and channel, camera powered (VOUT pin 4), and video signal wire on pin 6 (not swapped with a GND). If the OSD shows but no camera image, the problem is camera-side.
Can I power it straight from a 6S battery?
Yes — the 7–36 V input covers 2S–8S directly. The camera should be powered from the module's regulated 5 V output (pin 4), not from the battery.
How much range does 4 W give?
Range depends on antennas, terrain, and receiver quality more than raw wattage — but as a rule of thumb, each 4× power increase roughly doubles range. With directional ground antennas and clear line of sight, multi-kilometer to tens-of-kilometers analog links are achievable at 4 W. Plan the RC and telemetry links to match.
Does it work with digital FPV goggles?
No — the VT5805 is an analog transmitter (CVBS). It works with any analog 5.8 GHz receiver or goggles (including digital goggles fitted with an analog receiver module).
Related guides
- VT5804 5.8 GHz 2.5W Video Transmitter — User Manual
- ArduPilot — Telemetry Setup Guide
- LR900 Telemetry Radio — User Manual
- TRS — RC + Telemetry Combo User Manual
Written and maintained by the Robofusion engineering team.