Your VTX is blasting at 25mW when you set it to 800mW — and the OSD says everything is fine. The culprit is almost always a mismatched VTX table. I’ve debugged this on over 30 builds and the fix is the same every time: a properly defined VTX table that maps the protocol’s power levels and frequency bands to what your actual hardware supports. Here’s the exact configuration.
Step-by-Step VTX Table Setup
Step 1: Identify Your VTX Protocol
SmartAudio and IRC Tramp are the two protocols that matter. SmartAudio (TBS protocol) is used by TBS Unify, Rush, AKK, and most modern VTXs. IRC Tramp is used by ImmersionRC and Matek VTXs. You can typically identify yours in two ways: check the manufacturer spec sheet, or wire up and look at the Betaflight Ports tab — if UART TX is connected to the VTX data pin, it’s SmartAudio; if a single-wire bidirectional connection exists, it’s likely Tramp.
What happens if you get this wrong: The VTX won’t respond to band/channel/power changes at all. The OSD shows settings changing but the VTX never actually switches. You’ll be stuck on whatever the VTX was last set to manually.
Step 2: Load or Create the VTX Table
Betaflight 4.1+ requires a VTX table JSON definition. Go to the Video Transmitter tab in Betaflight Configurator (10.9+). You have three options:
Option A — Load from file: Most major VTX manufacturers publish JSON VTX tables. Download from the manufacturer’s website or the Betaflight VTX table repository. Click “Load from file” and select the JSON.
Option B — Use the built-in database: Betaflight Configurator 10.9+ includes a built-in VTX table database. Click “Load from database,” find your VTX model, and select it.
Option C — Manual entry: For obscure VTXs without published tables, you’ll build the table manually. See Step 3.
Verification: After loading, the VTX table panel should show populated bands, channels, and power levels. If the bands section is empty, the JSON failed to parse — check for syntax errors with a JSON validator.
Step 3: Manual VTX Table Construction (When No Table Exists)
If your VTX isn’t in any database, you’ll build the table from the spec sheet. The table needs three sections: bands (frequency groups), channels (specific frequencies per band), and power levels (dBm or mW).
Bands and channels: Each band (A, B, E, F, R, L) has 8 channels. Frequencies are standardized for analog — Band E channel 1 is always 5705MHz, Band F channel 1 is always 5740MHz. Define every band your VTX supports.
Power levels: This is where most custom tables break. Define each power level as a label and value. The value must match what the protocol expects — SmartAudio uses dBm * 1000 (25mW = 25000), Tramp uses milliwatts directly.
Example for a SmartAudio VTX with 25/200/600mW:
Power levels: 0=25mW (0), 1=200mW (1), 2=600mW (2)
Power values: 0=14, 1=23, 2=28
The “value” is the power index. The “dBm” is what SmartAudio uses internally (25mW ≈ 14dBm, 200mW ≈ 23dBm, 600mW ≈ 28dBm).
VTX Table Parameter Reference
| Parameter | SmartAudio (TBS) | IRC Tramp | Notes |
|---|---|---|---|
| UART Connection | TX only | TX + RX (single wire) | Tramp can be bidirectional |
| Power Value Format | dBm (25mW = 14, 200mW = 23, 800mW = 29) | mW (25, 200, 800) | Critical — get this wrong and power never changes |
| Band Support | 5 bands typical (A, B, E, F, R) | Same 5 bands | Some add L-band for Raceband 8 |
| Max Power Levels | 5 levels maximum | 5 levels maximum | Betaflight cap; if your VTX has 6 power levels, omit the least-used one |
| Pit Mode Support | Yes (0mW as power level 0) | Limited | Tramp pit mode is less reliable |
| Frequency Resolution | 1MHz | 1MHz | Both support exact frequency entry |
Common Mistakes & How to Avoid Them
Mistake 1: Leaving the power values at default (25/200/500/800).
The consequence: Your VTX actually supports 25/100/200/400mW, but the table claims 25/200/500/800. When you select “800mW” in the OSD, the VTX sends an unrecognized power index and either defaults to 25mW or ignores the command entirely. The fix: Match the power levels in the table exactly to your VTX’s spec sheet. If the spec sheet says the levels are 25/100/200/400, those are your table entries — nothing else.
Mistake 2: Using SmartAudio values for a Tramp VTX or vice versa.
The consequence: SmartAudio expects dBm; Tramp expects mW. If you define a Tramp table with dBm values, selecting 800mW sends the VTX a value of 29 — which Tramp interprets as “29mW” and either ignores or sets an absurdly low power. The fix: Double-check your VTX protocol before building or loading a table. SmartAudio VTXs say “SA” on the PCB or in the spec. Tramp VTXs say “Tramp” or “IRC”.
Mistake 3: Defining bands the VTX doesn’t actually support.
The consequence: The OSD shows Band A as an option, but selecting it does nothing because the VTX hardware doesn’t have that band’s PLL programmed. Your video feed stays on the previous channel. The fix: Only define bands confirmed in the spec sheet. Not all VTXs support all 5 bands — some budget VTXs only support B, E, and F.
Mistake 4: Forgetting to save and reboot after loading the table.
The consequence: The VTX table is loaded in the Configurator but not written to the FC. The next time you power cycle, the old (or empty) table is back. The fix: After loading the table, click “Save” in the Video Transmitter tab. Betaflight Configurator will prompt a reboot — let it happen. Verify the table persists by reconnecting and checking that the bands are still populated.
Mistake 5: Using an outdated Configurator that doesn’t support VTX tables.
The consequence: Betaflight Configurator versions before 10.7 don’t have a Video Transmitter tab at all — you’re stuck with the old vtxtable CLI commands. The fix: Update to Betaflight Configurator 10.9 or newer. The CLI method still works (vtxtable bands, vtxtable powerlabels, etc.) but it’s error-prone and the Configurator’s GUI is the reliable path.
⚠️ Regulatory Notice: The flight recommendations in this article should be followed in accordance with the latest 2026 drone regulations in your country or region. Always verify local laws regarding flight altitude, no-fly zones, remote ID requirements, and registration before flying. Regulations vary significantly between the FAA (US), EASA (EU), CAA (UK), CAAC (China), and other authorities.
VTX table issues are a subset of the broader video transmission ecosystem. Our guide to FPV VTX power settings covers SmartAudio control, pit mode, and channel management in depth. And if your video range is the real problem, our FPV VTX antenna selection guide explains how antenna choice multiplies your effective output power.
For builds where VTX integration matters, the TBS Unify Pro32 HV is still the gold standard for SmartAudio reliability — its VTX table works out of the box with Betaflight’s built-in database, and the pit-mode-on-power-up feature has saved me from cooking a VTX on the bench more times than I’d like to admit.