When this applies

Use this guide if the picture in your FPV goggles or monitor is missing, breaks up, cuts out or becomes poor much closer to the drone than expected.

The most useful first question is not “which part should I replace?” It is “does the problem come from the drone, the goggles, or the place I am testing?” Once you narrow that down, you can concentrate on the right checks.

What sends and receives the picture?

There are two sides to your FPV video setup:

• On the drone: the camera creates the picture. The video transmitter, usually called the VTX, sends it through an antenna. In some digital systems this transmitter is called an air unit.

• At your end: the video receiver, sometimes called a VRX, receives the picture through its antenna. It may be built into your goggles or monitor, or be a separate unit connected to them.

The picture travels like this:

Drone's camera → video transmitter and antenna → through the air → receiving antenna and receiver → goggles or monitor.

A problem anywhere along this path can spoil the picture. The location matters too: other transmitters can interfere, while buildings and other obstacles can block the signal.

Simplified FPV video path. Real UMT product photos are examples, not a recommended kit.

Before starting: keep tests safe and simple

• Remove the propellers before powering the drone for these tests. Keep it stationary; you do not need to fly it or run the motors to compare video equipment.

• Switch off and disconnect the battery and USB before changing antennas, cables or connections. Keep the required antennas attached whenever the video transmitter is powered.

• Keep powered tests short. Video transmitters can get hot without flight airflow; use a small fan for cooling where appropriate and follow your model's instructions.

• Stop if you notice smoke, a burning smell, damaged power wiring or unusual overheating. Do not reconnect damaged equipment just to demonstrate the problem.

Change one thing at a time and write down the result. Changing the channel, antennas and power together might improve the picture, but you will not know which change helped.

Step 1: rule out the easy things

Before comparing equipment, check:

• Have you removed the camera's lens cap? Are the goggles and drone powered, and are their batteries adequately charged?

• Are the antennas attached properly, with no obvious broken or crushed cables? Inspect with the power disconnected.

• Are the goggles showing the correct input? Goggles with several inputs may be set to a cable input rather than their video receiver.

• Does the video system match? For example, analogue goggles cannot receive DJI digital video just because both use a similar frequency. For a digital setup, check that your exact goggles and air unit are compatible and linked as their manual requires.

• For analogue video: set both ends to the same frequency. Compare the frequency number shown in MHz in their channel charts, not just “channel 1”. An automatic channel scan can stop on a nearby frequency that shows a picture but gives poor reception.

Also note what you see: static, a black screen, a frozen picture, moving lines, or a picture that only breaks up as you move away. A photo or existing recording is useful if you need help later.

Step 2: find out which side the problem follows

If you have access to another working drone or another working set of goggles, these comparisons are often more useful than trying lots of settings. Borrowing compatible equipment is fine; you do not need to buy anything.

Use equipment you have recently seen working correctly. It must use a compatible video system. Test one drone at a time, switching the other off to avoid creating interference yourself.

Start with short, stationary tests in a clear area. Keep the test position, distance and antenna direction the same. Leave the working drone's settings unchanged; tune or link the goggles to it using its instructions. Note any differences in channel or transmit power.

Do not place the drone right against the goggles: a very strong nearby signal can also cause problems.

Compare the original symptom, not just whether a picture appears. If the fault only happens farther away, a clear close-up picture cannot rule out either side. Do not fly farther to reproduce it. If you cannot reproduce the problem safely with the drone stationary, record the comparison as inconclusive.

Choose an available comparison test, then follow the result to the relevant checks. A close-up picture does not prove normal range.

Test A: use your goggles with a working drone

Use the same goggles that give you trouble, but receive video from a second drone you know works. Select its frequency or follow the digital system's linking instructions first.

• The second drone gives a good picture under conditions where the original fails: this points towards your original drone's video setup. Start with Step 3A, but compare locations with Test C if the results are unclear. A close-up picture alone cannot clear the goggles of a poor-range problem.

• The second drone also gives a poor picture: look more closely at your goggles, receiver and receiving antennas. However, interference at that location could affect both drones. Try Test B or Test C before blaming the goggles.

Test B: use your drone with a working receiver or goggles

Keep your original drone, but receive its video using another compatible receiver, monitor or set of goggles you know works.

• The picture is good on the other setup under conditions where yours fails: concentrate on your original goggles, receiver, receiving antennas or input settings. Go to Step 3B. If neither setup reproduces the original problem, the comparison is inconclusive.

• The picture is poor on both setups: try Test C before treating this as a drone-side problem. If the problem remains in another location, start with Step 3A.

These comparisons narrow down where to look; they do not prove that a particular component is faulty. Different antennas and receiver performance can affect the result, especially with poor-range complaints.

Test C: repeat the comparison in another location

Take the same equipment to another suitable open area with a clear path between drone and goggles. Keep the equipment settings unchanged. Avoid testing through walls or beside other powered video transmitters.

• The problem disappears or improves substantially: local interference or obstacles are likely contributing. Go to Step 3C.

• The problem remains: use Tests A and B to decide which side to investigate. A problem in several locations makes a single-location explanation less likely, but does not identify a failed part by itself.

Example: your drone looks bad through two sets of goggles, but a working drone looks good through both. That points towards your drone's video setup, not two faulty sets of goggles. Start with its antenna and settings before replacing the transmitter.

Using a repeater or separate video receiver?

If your setup includes a repeater that relays the video, or an extra receiver connected by a cable, simplify it where possible. Try receiving the drone directly with compatible goggles, leaving out the extra equipment.

If direct reception works but the longer chain does not, check the added equipment's antennas, power, settings and cables. If both fail, continue with the drone/goggles comparisons above. Only bypass equipment where your system supports it; do not improvise wiring.

No spare equipment available?

Start with Test C. If another location does not help, check the drone antenna and low-power settings in Step 3A, then the receiving-end checks in Step 3B. Without comparison equipment, these are checks, not proof of which side is faulty.

You do not need to buy parts. Tell support which comparisons you could not perform rather than guessing their results.

Step 3A: the problem appears to be on the drone

Check its antenna first

Inspect the antenna, cable and connector with power disconnected. A connector can look attached while being loose, and a crash can damage an antenna internally. If you already have a suitable working antenna, try that one change and compare the result.

Check these details:

• Frequency: the antenna must be designed for the video frequency your system uses.

• Matching labels: if both ends use circularly polarised antennas, match RHCP with RHCP, or LHCP with LHCP. These labels describe how the antenna handles the radio wave. Mixing the two can greatly weaken reception, even when the frequency matches.

• Other antenna types: some systems use linear antennas instead. Keep the manufacturer's recommended type unless you have verified a suitable alternative; not every FPV antenna needs an RHCP/LHCP label.

• Connector and placement: similar-looking screw connectors are not always compatible. Check the centre pin/socket as well as the threads. Keep the antenna clear of the battery and frame, following the equipment's mounting instructions.

Do not force small push-on connectors or pull them by the cable. If you cannot tell whether an antenna is suitable, send its model or a clear photo to support.

Circular antenna labels must match. Check frequency and connector suitability too.

Check for pit mode or low-power mode

Pit mode deliberately makes the video signal very weak, or switches transmission off on some systems. It lets pilots work on a drone without interfering with others. If it remains active, you may get a picture nearby but lose it almost immediately as you move away.

A separate low-power mode may reduce transmission strength while the drone is sitting on the ground. That can make a ground test look worse than expected. It is not necessarily a fault, and it is not the same setting as pit mode.

Check the transmitter's menu or indicator lights against its manual. Do not assume pit mode automatically switches off when the drone is armed, and do not arm the drone just to test this.

If your drone uses Betaflight Configurator, the setup software used by some drones, check whether a selected video setting actually takes effect. If it does not, the drone's main electronics board (the flight controller) may not be communicating with the transmitter correctly.

Ask for help with this configuration rather than trying settings from a different transmitter model.

Check whether heat or power is involved

• Works when first switched on, then gets worse: let it cool with power disconnected. Repeat a short test with suitable airflow. This suggests checking cooling, but is not proof of an overheating fault.

• Existing footage shows lines or cut-outs during throttle changes: check the power wiring and connections. Electrical noise or an inadequate power supply can affect video. Do not run the motors just to recreate this for the guide.

• No camera picture at all: inspect the camera cable and its connections with power disconnected. Note any warning or unusual light pattern. A working transmitter cannot send a useful camera picture if the camera or its connection is not working.

Do not change the supply voltage, add components or rewire the drone unless you understand the exact model's requirements. These are next steps for a specific diagnosis, not fixes to try at random.

Step 3B: the problem appears to be at the receiving end

Check your goggles or separate video receiver:

• Recheck the selected input and frequency. If there is a plug-in receiver or video cable, inspect its seating and connections with power off.

• Inspect each receiving antenna and any extension cable. Check frequency suitability and, where applicable, RHCP/LHCP matching just as you did on the drone.

• If you use a flat patch antenna, check its instructions for the receiving direction and point it towards the drone. It is directional: it does not receive equally well from every direction.

• If you already have a suitable working antenna or cable, swap only that part and repeat the same test.

If several working drones have the same problem only with your goggles, in more than one location, send those comparison results to support. That is much more useful than simply reporting “bad range”.

Step 3C: the location appears to be contributing

A video setup can work well in one place and poorly in another. Other video transmitters, some Wi-Fi networks and nearby obstacles can affect reception.

• Coordinate frequencies with other pilots before powering up. Do not change channels while someone is flying without agreeing it first.

• Repeat a stationary test with other video transmitters switched off where practical.

• Keep a clear path between the drone and receiving antennas. Check whether moving away from a wall or obstruction improves the picture.

• If testing another permitted channel, change it correctly at both ends where required and record the result.

Do not jump straight to maximum transmission power. It may not solve interference, and it adds heat. Use only settings permitted where you operate.

Other symptoms: what to check next

Black screen, but text is still visible

The text showing battery voltage and other flight information is called the on-screen display (OSD). Here, this means flight information from the drone, not the goggles' own menus or warnings.

On an analogue build, flight-controller OSD text without a camera picture is a reason to investigate the camera, its power and its video connection first. It does not automatically mean the transmitter is broken.

For more detailed camera checks, use our analogue FPV camera troubleshooting guide. Do not attempt soldering or bypass wiring you are unfamiliar with.

Picture works, but flight information is missing

If the camera image is clear but the OSD text is missing, investigate the OSD settings and its connection to the flight controller. This is a different problem from poor video reception. The correct setup depends on your video system, so avoid copying another build's wiring or commands.

Rolling, tearing or black-and-white analogue picture

Check the exact frequency and connections first. PAL and NTSC are analogue video formats. If your equipment offers this setting, follow its instructions to select a compatible format for the camera and display. If the picture still rolls or tears, report the exact camera and receiver models to support.

Digital system connected, but no image or an error appears

Write down the error exactly and photograph the indicator lights. Check camera connections with power disconnected, then use instructions for your exact air unit and goggles. Do not force delicate camera connectors.

Software compatibility can matter, but flashing firmware or resetting everything is not the first step. Check the manufacturer's instructions before updating; not every system requires identical version numbers at both ends.

Wobbly picture, or only the recording looks bad

A wobbly picture can come from vibration or a loose camera mount. Inspect the mounting with power disconnected. Compare any existing recording with what you saw in the goggles: a recording-only issue should not automatically be treated as poor video reception.

How to confirm an improvement

Repeat the same safe comparison after making one change. Note whether the original symptom has gone away, not just whether a picture appears briefly.

A clear picture close by does not prove normal range. Do not resume flying with unexplained cut-outs, or fly further until the picture fails as a way to test the repair.

Still having trouble?

Contact Unmanned Tech through our Help Centre. Include:

• The drone, camera, video transmitter and goggles/receiver models. If you do not know the names, send clear photos of their labels.

• What you see, when it happens, and whether it started after a crash, update or change to the build.

• Antenna names or photos, your video channel/frequency, and power setting if known.

• Clear photos of the installation with power disconnected, plus an existing video clip if available.

• Your comparisons: “My goggles work with drone B, but drone A looks bad on both sets of goggles” or “The same setup works at location B but fails at location A.”

If you could not complete a test safely, say so. Do not buy spare parts, dismantle unfamiliar equipment or reconnect a damaged build just to provide evidence.

Further help for your particular system

You do not need to read every manufacturer's guide. Choose only the one relevant to your equipment or the step you are checking:

• Analogue transmitter settings: Betaflight's video transmitter guide explains pit mode, low-power mode and checking whether settings have taken effect.

• DJI O4: DJI's O4 support page covers compatible goggles, cooling and model-specific checks.

• Walksnail: Caddx's download centre contains manuals for the different goggles and air units.

• HDZero: HDZero's video transmitter FAQ explains video symptoms and indicator lights.

• Understanding antennas: FPV antenna guide explains antenna types, matching and placement.