Components
FPV video systems: analogue and digital
The video link is the one you actually fly on, and it fails in a completely different way to the control link, which is why it deserves its own decision rather than an afterthought bolted onto the frame build.
A flight controller losing its control link fails safe, usually into a return-to-home or a controlled descent. A video link has no such fallback: when it degrades, the pilot simply sees less, or sees nothing, and has to fly through that or land blind. The chain behind that picture is also longer than most builders expect, and any stage in it can be the reason the goggles show less than the camera deserves.
- CameraTurns light into a video signal
- Video transmitter (VTX)Encodes and radiates that signal, on analogue or digital
- Antenna, aircraft sideShapes the pattern the signal leaves the quad in
- Antenna, ground sideShapes what actually gets picked up by the goggles or receiver
- Receiver or moduleTunes or decodes the incoming signal
- Goggles or screenWhat the pilot actually sees
Whichever of these six is weakest sets the result for the whole chain. A good camera behind a detuned VTX, a strong VTX into a badly mounted antenna, a clean signal into goggles with a worn screen: in every case the weak stage is the one that decides what the pilot sees, and spending money on any other stage first does not fix it.
Analogue or digital: the decision this page actually turns on
Everything downstream, cost, latency, how a bad link fails, follows from this one choice, so it is worth framing properly rather than as "digital is the new one, so it is better." Analogue video is a continuous signal: the camera's picture goes out as a waveform with no encoding step in between, which is why it has effectively no processing latency and why it degrades gradually. As the signal weakens, an analogue picture gets noisier, breaks into static and colour banding, and a pilot who knows the site can often keep flying through that degraded picture because enough of it survives to judge distance and orientation.
Digital video encodes the camera's picture into a compressed data stream, sends it, and decodes it back into a picture at the goggles. That encoding and decoding step is where the added latency comes from, on top of whatever the analogue chain would take, and it is also why digital systems tend to hold a clean, artefact-free picture right up until the link cannot keep up, at which point the picture freezes, blocks up or cuts out rather than fading. A pilot flying through a weak digital link does not get a gradually worsening view to judge distance by, they get a good picture and then, abruptly, very little.
Cost and repairability follow the same split. Analogue cameras, VTXs and goggles are the cheaper way into the hobby and the parts are largely interchangeable across brands, so a damaged camera or VTX is a small, separate purchase. Digital systems generally cost more to get into, and the camera, VTX and receiver are commonly sold, and sometimes firmware-locked, as a matched set from one manufacturer, so a single damaged part can mean replacing more of the chain than the part that actually broke.
| Category | Analogue | Digital |
|---|---|---|
| Latency | Effectively real time; a continuous waveform with no encode/decode step | Higher than analogue, from the added encoding and decoding stage |
| Degradation behaviour | Fades into static and noise a pilot can often still fly through | Holds a clean picture, then freezes or cuts out with little warning |
| Cost | Lower entry cost, camera and VTX widely interchangeable | Higher entry cost across camera, VTX and receiver |
| Repairability | Parts are largely mix-and-match across brands | Camera, VTX and receiver often sold, and paired, as a matched set |
VTX output power is not the lever it looks like
A video transmitter's output power, rated in milliwatts, looks like the obvious dial to turn for more range: double the power, double the distance. Radio propagation does not work that cleanly, and antenna choice and polarisation usually change what actually arrives at the goggles more than an increase in transmit power does. A well-matched antenna pair recovers a picture that a higher-power VTX into a badly matched antenna cannot, and more power into a bad antenna setup mostly buys heat, not a longer range on the picture.
Regulation
VTX transmit power is regulated as radio spectrum use, separately from the drone flight rules covered elsewhere on this site, and the licence-free power limit is set at national level rather than by one EU-wide figure. A power level or a frequency allocation that is licence-free somewhere else in the world is not automatically licence-free in the EU. This page will not state a specific milliwatt limit here: that is exactly the kind of figure that differs by country and changes over time, and a wrong number copied from an old forum post is how a reader gets fined. See regulation for how EU-wide and national rules generally divide up, and check your own country's telecommunications regulator for the figure that actually applies to you.
Antennas: why the pattern shape decides whether you keep the picture in a turn
Two antennas sit at the ends of the over-air hop, one on the VTX, one on the goggles or receiver module, and both come in one of two polarisations. The difference between them is the shape of the field each one radiates, not a range figure printed on the packaging. A linearly polarised antenna sends its signal oscillating in a single plane, horizontal or vertical. A circularly polarised antenna splits the same signal across both planes with a 90 degree phase shift between them, so the field spins as it travels rather than sitting in one plane.
That spin is what matters in the air. A circularly polarised link keeps its coverage regardless of how the aircraft is oriented relative to the receiving antenna, while a linear link's strength depends on the alignment between the two antennas, and on a quad rolling and yawing through a turn that alignment changes several times a second. That is why circularly polarised antennas, not linear ones, are the default pairing for FPV video, and why a picture can drop out mid-turn even at close range on a linear setup that would hold perfectly well flying straight and level.
Mixing the two is possible, some racers run a linear antenna on the aircraft for weight and durability with a circular antenna on the goggles, but it costs roughly 3 dB, about half the signal power, compared with matching the pair. Match polarisation, and match the rotational sense, right hand or left hand, on both ends unless there is a specific reason not to. Both antennas usually sit clear of the frame's carbon on a printed mount rather than bolted flush to it, alongside the camera itself; see printed parts for what holds up in that role and what does not.
The 5.8 GHz band is shared airspace: channel discipline is a safety issue
Most analogue and digital FPV video runs in the 5.8 GHz band, split into a number of named channels, and two pilots on overlapping channels at the same site do not each get a slightly weaker picture, they get a fight for the same slice of spectrum that can drop either picture, or both, without warning. This is a different problem to the VTX's own connection to the flight controller over its control UART: that link only sets channel and power from the cockpit, it does nothing about what another pilot's transmitter is doing on the same frequency at the same field.
Treat channel coordination at a shared site as a safety step, not an etiquette one. Losing video feed mid-flight means losing your only view of terrain, people and other pilots for however long it takes to recognise the loss and react, and an aircraft with no observer keeping eyes on it directly has no backup for that gap. Agree channels before anyone launches, and do not assume two systems are automatically clear of each other just because one is digital and one is analogue.
Goggles or a screen, for a first build
A beginner has one more decision ahead of all of the above: goggles, which put the feed directly in front of the eyes and block out the surrounding world, or a screen watched while some awareness of the real surroundings remains. Goggles are what most of this hobby flies on: full field of view, no glare, and head tracking on boxes that support it. They also remove peripheral awareness completely while worn, which is one reason FPV flying interacts with the visual-line-of-sight rule differently to flying on a screen; see regulation for how that rule actually works.
A screen costs less, lets a beginner learn the sticks with a wider sense of what is happening around the aircraft, and does not commit anyone to a goggle purchase before they know whether FPV flying is for them. Starting on a screen is a reasonable choice, not a lesser one; see start for the path this site recommends for a first build overall.
The DVR question: record in the goggles, or record on the aircraft
One more decision sits inside "digital" and "analogue" alike: what actually gets recorded, and where. Most goggles include their own DVR, recording whatever reaches the goggles after the camera, VTX, antennas and any signal loss along the way. That is convenient, needs no extra weight on the aircraft, and records exactly what the pilot saw, static, dropouts and all, because it is downstream of the whole chain rather than upstream of it.
An onboard DVR, a small recorder wired directly to the camera on the aircraft, sidesteps the video link entirely and records the camera's own output before it goes anywhere near a VTX. That is closer to the picture quality the camera is actually capable of, at the cost of extra weight, extra wiring, and a separate device to manage and retrieve footage from after every flight. Neither answer is more correct than the other: the goggle DVR answers what the pilot actually saw, the onboard DVR answers what the camera actually recorded, and the two answers diverge exactly when the video link had a bad moment mid-flight.
None of this replaces flying the setup before trusting it somewhere that matters. A chain that reads well on this page can still surprise a pilot the first time it goes through trees or into direct sun. For the electronics stack the VTX sits alongside, see flight controllers; for the mounts that hold the antennas and camera in place, see printed parts; or go back to components for the rest of the build.