FPV Drone VTX Table Setup: SmartAudio, Tramp Protocol, and Power Level Definition — 2026 Guide

Your OSD shows “VTX: DEVICE NOT READY” and changing channels from the radio does nothing. The VTX is wired, powered, and transmitting — but Betaflight can’t talk to it. Nine times out of ten, it’s the VTX Table. You either loaded the wrong table, defined power levels incorrectly, or skipped it entirely. Here’s the fix.

VTX Table Basics: What It Actually Does

The VTX Table is a JSON structure inside Betaflight that maps power levels, frequency bands, and channel indices to what your specific VTX hardware expects. Without it, Betaflight sends commands in a format the VTX doesn’t understand. SmartAudio and Tramp are protocols — they define how commands travel, not what the valid values are. The table defines the values.

Every VTX has its own band/channel layout and its own power level mapping. A TBS Unify Pro 32 HV expects power level 0 to mean 25mW and level 4 to mean 1W. A Rush Tank Ultimate expects level 0 = pit mode, level 1 = 25mW, and so on. If you load the wrong table, Betaflight sends “set power to level 3” and the VTX interprets that as whatever its level 3 means — 600mW when you wanted 200mW, or pit mode when you expected full blast.

Step-by-Step VTX Table Setup

Step 1: Find your VTX’s exact model and power levels. Look up the manufacturer’s spec sheet. Write down power levels in milliwatts in order from lowest to highest. Example for TBS Unify Pro32 HV: Pit/0, 25, 100, 400, 1000. Example for Rush Tank Solo: Pit/0, 25, 100, 200, 400, 800. The order matters — level indices count from 0 upward.

Step 2: Open Betaflight Configurator → Video Transmitter tab. You’ll see two sections: a “VTX Table” file area at the top and manual band/channel/power entry below. The fastest (and least error-prone) method: load a pre-made JSON table from the manufacturer.

Step 3: Load the manufacturer’s VTX Table JSON file. Most reputable VTX makers provide a downloadable .json file. TBS has theirs on the product page. Rush includes it in the manual PDF. HGLRC publishes them on their support site. Click “Load from file” in the VTX tab, select the JSON, click “Save.” Done.

Step 4: If no manufacturer JSON is available, build the table manually. This is where most people mess up. You define three things:

Bands: Every band is 8 channels with specific frequencies (in MHz). The standard bands are:
– A (Boscam A / Team BlackSheep): 5865, 5845, 5825, 5805, 5785, 5765, 5745, 5725
– B (Boscam B): 5733, 5752, 5771, 5790, 5809, 5828, 5847, 5866
– E (Boscam E / DJI): 5705, 5685, 5665, 5645, 5885, 5905, 5925, 5945
– F (Fatshark / ImmersionRC): 5740, 5760, 5780, 5800, 5820, 5840, 5860, 5880
– R (Raceband): 5658, 5695, 5732, 5769, 5806, 5843, 5880, 5917

Add all bands your VTX supports. Most support A, B, E, F, R. Some add L-band (low band, 5362-5566) for long range. Each band needs a name, a single-letter identifier, and 8 frequencies.

Power Levels: Define exact mW values matching your VTX. Label them clearly. Values must be integers. Pit mode is typically level 0 with value 0 or 1. You can have up to 8 power levels.

Step 5: Verify bidirectional communication. After saving the table, go to the Video Transmitter tab and check “Device ready: Yes.” If it says “No,” SmartAudio/Tramp isn’t being received. Check wiring (VTX SmartAudio wire to a free FC TX pad), check the Ports tab UART assignment (Peripherals → VTX), and verify the protocol matches your VTX (SmartAudio 2.0 for TBS, SmartAudio 2.1 for Rush, IRC Tramp for Tramp-based VTX).

Step 6: Test power level switching. Change power via the OSD menu (yaw left + pitch forward, then VTX settings) or the Betaflight Configurator VTX tab. Wait 2 seconds and verify via the OSD element or an external RF power meter. Some VTX LEDs change color per power level — learn your VTX’s indicator pattern.

Power Level Definition Table

Note: DJI air units and Caddx Vista use MSP-VTX, not SmartAudio/Tramp. The VTX Table still applies but the underlying protocol is different — covered in our DJI O4 Air Unit installation guide.

Common Mistakes & What Most Pilots Get Wrong

Mistake 1: Loading the wrong VTX Table. You have a Rush Tank Solo but load the TBS Unify Pro32 HV table. Betaflight shows “Device Ready: Yes” because both use SmartAudio 2.x, but when you select “400mW,” the Rush interprets the level 3 command as 200mW (its actual level 3) because the power-to-index mapping is completely different.

Consequence: You think you’re at 800mW but the VTX is actually at 200mW. Range is garbage and you blame the antenna.

Fix: Always load the exact table for your VTX model. If you can’t find it, build it manually from the spec sheet. Verify by checking the VTX’s own LED indicator or a power meter.

Mistake 2: Defining power levels with wrong index order. You type [800, 400, 200, 100, 25] instead of [25, 100, 200, 400, 800]. Betaflight sends “level 1” and the VTX goes to 400mW because that’s position 1 in your incorrectly-ordered table.

Consequence: Power level control is inverted or scrambled. Your OSD says 25mW but the VTX is blasting 800mW.

Fix: Power levels must be in ascending order. Smallest first, largest last. If your VTX supports pit mode, it goes at position 0 with value 0.

Mistake 3: Using incorrect frequency values in a custom table. Frequencies must be exact: Raceband channel 1 is 5658, not 5660. A 2MHz offset means your receiver might still pick up the signal weaker, but it’s operating at the wrong tuning point. On digital systems like HDZero or Walksnail, frequency mismatch causes complete link loss.

Consequence: Goggles have trouble locking on, range is reduced, or other pilots on nearby channels get interference because your actual transmission bleeds into their frequency.

Fix: Copy frequencies from the Betaflight presets repository or the manufacturer’s published table. Don’t type them from memory. Double-check against the official band chart.

Mistake 4: Running pit mode on a VTX that doesn’t support it. You define power level 0 as “Pit / 0mW” but your VTX (like the Zeus Nano) has no pit mode — it starts at 25mW. When Betaflight sends level 0, the VTX either ignores it or defaults to max power.

Consequence: At the starting line, you’re either invisible (won’t affect others but you have no video) or you’re accidentally at 400mW blasting everyone else’s feed.

Fix: If your VTX doesn’t support pit mode, don’t define a pit level. Start at the actual minimum: usually 25mW.

⚠️ Regulatory Notice: VTX power output is regulated in most countries. In the US (FCC), unlicensed 5.8GHz transmission above 1W requires an amateur radio license. In the EU (ETSI), 25mW is the legal limit for unlicensed 5.8GHz FPV without specific authorization. The UK (Ofcom) enforces similar limits. Some regions prohibit pit mode switching at events unless coordinated by race directors. Always verify your local 2026 transmission power regulations before flying. Operating above legal limits can result in equipment seizure and fines.

Once your VTX Table is correct, the next thing to dial in is actual power output management — we broke down range estimation and multi-pilot interference in our VTX power settings guide. And if you’re still sorting out which antenna to pair with that VTX, our VTX antenna types comparison walks through gain, pattern, and polarization selection.

For clean power delivery to a high-output VTX, capacitor installation is non-negotiable — the Panasonic 35V 1000µF low-ESR capacitor is what I run on every build pushing 800mW or more. It kills the ripple that causes horizontal lines in your feed. Available at uavmodel.com.