Your quad’s video transmitter (VTX) processes the video from your FPV camera and transmits the video to your goggle’s receiver. Typically, the VTX connects to your FPV camera and flight controller. Depending on your configuration, you may control the VTX from your radio transmitter or goggles. When choosing a video transmitter, the most important considerations are your required range and transmitting band compatibility with the video receiver in your goggles.
Scroll down to see our VTX recommendations.
Digital HD vs. Analog
DJI HD FPV System
Getting this out of the way, your first decision is whether you want to fly analog or HD. If you are using the Caddx (DJI) Air Unit, Caddx Vista, or Runcam Link paired with the DJI FPV Goggles, the latter half of this article won’t apply to you because all of the DJI options share mostly the same specs. The concepts for analog are the same, except you’ll be streaming 720p resolution video rather than analog video (think VCR quality).
If you’re debating between DJI HD vs. analog for your quad build, it generally comes down to price and latency. The DJI system is much more cost prohibitive if you’re on a small budget, but the video quality is arguably the best, and no contest when compared to analog. A combination of the goggles, air unit, and FPV camera hovers around $700. This doesn’t include all the other parts you’ll need for your quad! If you’re a racer or on a smaller budget, you’ll likely opt for an analog VTX, which tends to have cheaper options and lower latency (faster responsiveness) than DJI.
DJI also recently released the successor to the Goggles v2 and Air Units, the Goggles 2 and O3 Air Unit. Learn more about how these DJI products compare and what's right for you.
In our How to Get Into FPV post, we recommended that if you’re starting out in FPV, go from the simulator to a tinywhoop to a larger quad. However, because even the smallest DJI unit is so heavy and shielded, it's typically not suited for tinywhoops. There are a few bind-and-fly DJI tinywhoops that use a naked Vista Unit, and you can build one yourself, but it is worth keeping this in mind. Alternatively, you can graduate to a 2.5 inch whoop after you feel comfortable in the sim.
For pilots who want the best of both worlds, you have two additional options:
- Using DJI FPV goggles with a 3rd-party analog video receiver module, which allows you to use the DJI goggles along with analog video transmitters. This set up allows the pilot to switch between low latency analog flying, and switch to DJI HD flying for other flying scenarios.
(One note on the DJI FPV system is that even though DJI has focused less on developing its FPV business, its video quality still reigns supreme, since its initial release in 2019. The company continues to manufacture the goggles and outsource production of compatible air units to Caddx and RunCam. As of time of writing, there have been rumors of a V3 of the goggles which may also indicate a new air unit VTX, and we’ll update this post to reflect that if/when it happens.)
- Using the HDZero system, which we discuss below.
More recently, in an effort to fill the void for pilots who want all of the good things that come with analog along with excellent video quality, HDZero entered the market with the intent of building an accessible HD video system. Jump to today, and HDZero now offers a well-rounded video ecosystem with their own set of goggles, video transmitters in all shapes and sizes, and a video receiver compatible with most goggles.
The HDZero Goggles are now the most versatile goggles available for FPV today. Not only does it come with HDZero compatibility right out of the box, the HDZero Goggles can be configured to work with Walksnail and analog video receivers. If you don't want to use DJI, this is the best ecosystem to start with.
The HDZero system is open-source from the software to the hardware which appeal to many in the community who dislike that DJI is a completely closed system.
Even more recently, Walksnail, a subsidiary of Caddx introduced their Avatar goggles along with a HD VTX that rivals the DJI system. FatShark also introduced HD goggles, the Dominator HD, which is exactly the same as the Avatar. This system was just released as of June 2022. While the jury is still out on performance, for new pilots, this is a new HD VTX ecosystem that can eventually rival DJI and HDZero.
We believe the future of FPV video is HD video, but there are certainly still limitations to the technology, like latency and interference, that make analog the better choice for some people. If price allows, we recommend going with a HD video transmitter and receiver setup, but recognize that that's not possible for a lot of people as well. You can price out your quad on QuadPartPicker and see what’s right for you.
Learn more about the different FPV HD digital video systems in our article about picking FPV Goggles.
One of the most important factors when choosing a video transmitter is the output power. This is measured in milliwatts (mW). The output power of your VTX determines how much video range you’ll get with your quad. Most modern VTXs have switchable output power which allows you to configure the mW output to suit your flying needs. The key is to find the range that works for you, rather than to max it out for future-proofing.
In general, these are the differences and trade-offs between low and high power VTXs:
Low mW VTX:
- Provides less range
- Consumes less power
- Produces less heat
- Produces less interference with other pilots
High mW VTX:
- Provides more range
- Provides better signal penetration for flying in places with walls or obstacles
- Consumes more power
- Produces more heat, which contributes to the degradation of the VTX
High output signals can bounce off of other surfaces causing interference with your goggles, and other pilots’ signal with their quads.
Typically, choose a lower mW VTX (25 mW) if you’re flying indoors and/or racing. And choose a higher output (1W+) for longer range flights. Or anything in-between to fit your preferences. You want to find a good balance for your flying needs.
When you’re browsing for video transmitters, retailers usually denote switchable power by noting the power settings in the title or description of the product (ie. 25mW/100mW/250mW/600mW). If output power switching is available, the retailer will also note the protocol for switching (ie. SmartAudio, Tramp, physical switches)
For DJI HD pilots, the max power output on the Caddx (DJI) Air Unit and Caddx Vista units is officially 700mW. However many users modify their units to 1200mW without issue.
Find video transmitters by max output power on QuadPartPicker.
The main settings you’ll likely be toggling between the most are channels and max power output. Many modern VTXs allow you to change their settings from your goggles via Betaflight firmware or from your radio transmitter via EdgeTX, OpenTX or other proprietary firmware. These features come in the form of SmartAudio or Tramp communication protocols. If you purchase a VTX with SmartAudio or Tramp enabled and have compatible goggles or radio, you’ll be able to configure these settings.
Why Choose a VTX With SmartAudio or Tramp?
If you plan to fly with other people, being able to quickly configure your video channel will reduce the likelihood that you transmit video to someone else’s goggles nearby. It is common courtesy if you’re flying around other pilots to yell out your intended channel around other pilots before you power on. This way, you don’t interfere with anyone else’s video and TX feeds, thereby lowering the chances of causing an accident.
Being able to quickly toggle your max mW output allows you to use a high max power VTX at a lower power output in indoor racing situations, or to reduce the interference you’re getting from signals bouncing off of nearby surfaces.
For most modern quad builds, we suggest getting a VTX that has multiple power levels and supports SmartAudio or Tramp. The cost difference is almost negligible for the versatility.
Frequency, Channels, and Bands
If you’ve ever dealt with tuning the radio or a TV antenna, this is essentially what you’re doing when pairing your VTX to your goggle’s video receiver. To ensure a quality signal, you need to match the band, then the channel of your VTX and VRX.
If you fly alone, this isn’t as important. You just need to ensure that the technical specs of your goggles support the frequency, channel, and band as your VTX. If you don’t, you will not be able to get a signal from your VTX to your goggles. That said, it’s beneficial to understand these nuances when you want to casually fly with your friends or attend a race.
Frequency - Almost all video transmitters run on 5.8GHz frequency.
- Analog VTXs run on 30MHz bandwidth.
- DJI, Caddx Vista, and Runcam Link units on the 25mbps bitrate run on 20MHz bandwidth.
- DJI, Caddx Vista, and Runcam Link units on the 50mbps bitrate run on 40MHz bandwidth.
Band - Every VTX will be compatible with at least 1 band. This is denoted by a capital letter (A, B, D, E, F, R, etc). Check your VTX’s documentation to see what bands your VTX is compatible with and confirm that it is compatible with the video receiver on your goggles.
Channel - Every band will support up to 8 channels. This is denoted by a number (1-8). You will also have to make sure your VTX and your goggles are on the same channel of the same band.
Depending on the VTX you select, you can change your VTX’s channel via your radio or your goggle’s OSD if you have one that is SmartAudio or Tramp-enabled. If not, typically the VTX will have a physical push-button or dip-switch on the VTX itself. Refer to your VTX’s documentation to see how channels are changed.
When you’re at an FPV event or flying at the park with other pilots, assume everyone is flying on the 5.8GHz frequency, on either 20MHz, 30MHz, or 40MHz bandwidth. Depending on what VTX each pilot is using, they could be on any band (A, B, D, E, F, R, etc). Each pilot needs to be on a different channel within these bands. You need to make sure no one else is using the same band and channel as you are before you plug in. This is not only common courtesy, but you can severely impact another pilot’s flying if you don’t do this.
If you’re flying DJI HD, realistically, you can only fly with up to 8 pilots because you’re limited to the 8 channels in the DJI band. Here are some tips when flying with DJI or Caddx Vista units in groups:
- Don’t fly near analog pilots. Your goggles can cause interference with analog goggles.
- Fly only at 25mbps. If you fly at 50mbps, you can cause even more interference with analog pilots.
- If you’re flying with 8 total DJI pilots, the person using channel 8 should plug in last because that is the public channel.
Integrated or Standalone VTX
As a result of the proliferation of the FPV hobby, part markers have created a lot of different parts to choose from, especially if you fly analog. Among some of the options, you can find VTXs that are integrated with a flight controller or VTXs that also integrate a radio receiver. Your choice for going with integrated or standalone is based on preference and total cost.
The argument is: if you buy integrated parts, you have to replace the entire part if one of the functions is damaged or becomes non functional. On the flip side, if you buy integrated parts, they tend to work seamlessly with each other and physically fit well together. You can use QuadPartPicker to choose a configuration that is right for you. You can find all-in-one flight controllers with a VTX integrated, or you can find standalone VTXs that suit your needs.
If you want something that just flies with the least amount of building, consider a flight controller with an integrated VTX. If you’re looking for more range, more versatility, or certain features, you’re better off getting a standalone VTX.
Find VTXs on QuadPartPicker.
Find flight controllers with an integrated VTX on QuadPartPicker.
Connecting Your VTX
Most VTXs these days support a range of voltages, meaning you can solder the power leads to the battery pads of your flight controller. That said, most flight controllers have a dedicated VTX pad to solder to, and this is going to be the most advisable connection — in the event that you experience a voltage spike or drop, you don’t destroy your VTX or lose connection to your VTX. If you are using a power distribution board in combination with your flight controller, the PDB will likely have a pad to power your VTX as well.
Where you attach your FPV camera depends on whether your VTX comes with an OSD, or if you’ll be using the OSD that comes with your flight controller. If you purchase a VTX with SmartAudio or Tramp, it will very likely come with an OSD. In this case, you will attach your FPV camera to your VTX, and your VTX to your flight controller. Refer to the wiring diagrams for your VTX and flight controller to see what wires needs to attach to what.
Most modern day video transmitters come with U.FL (sometimes called IPEX) or MMCX antenna connectors. These are small connectors that snap onto your VTX. In some cases, your VTX will come with a U.FL or MMCX adapter to SMA or RP-SMA that will allow you to use more common types of antennas with larger connectors.
Connector types include:
- Never turn on your VTX without an antenna attached. You can burn out your VTX immediately.
- Use an adapter if possible. In the event of a crash, antennas usually get caught up the most and can cause strain on the VTX, potentially damaging or rendering the entire VTX unusable.
Find antennas on QuadPartPicker here.
RHCP vs. LHCP Antennas
On the note of antennas, when selecting an antenna to use with your VTX or VRX, you’ll encounter these acronyms. Both of these are circular polarized antennas. RHCP is right-hand circular polarized, LHCP is left-hand circular polarized. The best practice is to match RHCP with RHCP, and LHCP with LHCP. You can still get a RHCP signal with LHCP, but you will get less range and more interference, especially if flying around other pilots. If you fly with the DJI goggles, use LHCP antennas on your VTX because the goggles come with LHCP antennas. If you upgrade the goggle’s antennas, you can choose either RHCP or LHCP as long as they match.
When selecting a VTX to suit your flying needs, make sure you account for the range you need. Unless you have major budget constraints, opt for one with SmartAudio or Tramp. And double confirm that your VTX and goggles’ receiver have compatible bands. Otherwise, connector differences are easy problems to solve with a variety of adapters and pigtails. Digital HD video options are limited and expensive, but your build will be a lot more streamlined.
QuadPartPicker’s VTX Recommendations
Analog Video Transmitters
The Best Analog VTXs:
TBS Unify Pro32 HV - Dubbed one of the best analog VTXs made with a 1W+ output power.
TBS Unify Pro32 Nano - Made for racers, but comes with 500mW output power.
RushFPV Tank Mini - For smaller frames with a 20x20 mount with 800mW output power.
RushFPV Tiny Tank - Packs less power (up to 350mW) compared to other VTXs in the Tank lineup, but is tiny and weights only 1.4 grams.
Excellent Value Analog VTXs:
Eachine Nano V2 - A great alternative to the TBS Pro32 Nano 5G8 at almost half the price.
AKK FX3 Mini - A 20x20mm-mounted 600mW output power VTX for just $20.
HD Video Transmitters
Typically, you can purchase a kit that also comes with a compatible FPV camera.
Caddx Air Unit Kit - For larger 5+ inch quads with a full size DJI FPV camera.
Caddx Naked Vista Kit - Removes the shielding and heatsink from the Vista and used primarily for tinywhoops. Beware of overheating due to the lack of heatsink.
Runcam Link Phoenix Kit - It’s like the Vista, but comes with a Runcam Phoenix HD FPV Camera.
DJI O3 Air Unit - The successor to all of the above, and compatible with both the DJI Goggles 2 and DJI Goggles v2.
HDZero Freestyle - Arguably the best HDZero VTX out there to-date with 1W+ output power.
HDZero Whoop VTX - 25.5x25.5 mounted HDZero VTX with up to 200mW output power.
HDZero Race VTX - 20x20 mounted HDZero VTX with up to 200mW output power.
Walksnail Micro VTX Kit - a 25.5x25.5 mounted Walksnail Avatar / Fat Shark Dominator VTX with a micro FPV camera
Walksnail Nano VTX Kit - a 25.5x25.5 mounted Walksnail Avatar / Fat Shark Dominator VTX with a micro FPV camera
Walksnail Mini 1S VTX Kit - an ultra-light 25.a 25.5x25.5 mounted Walksnail Avatar with a nano FPV Camera
Fatshark VTX Kit - the same exact VTX as the Walksnail VTX, but Fatshark-branded
Want to consider your VTX choice along with your goggles? Check out our guide to choosing FPV goggles in 2023.
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