Updated 7/6/2016 – Added the FPV Ninjas and Range Video offerings.
Updated 7/21/2017 – Added in Betaflight OSD compatibility and adjusted suggestions.
This edition of our buyers guide series will take an in depth look at FPV video transmitters. Video transmitters are responsible for taking the video signal from your flight camera or OSD and broadcasting it over the airwaves. As such, they are the critical component of your FPV setup that allows you to see what your quadcopter is doing without running a wire to it. Here are the features of any given video transmitter that you should pay attention to when deciding what to buy:
Power Output – The porawer output of the video transmitter determines how much power is radiated through your transmitter. More power generally means more range, but comes with the side effect of causing increased noise on the sidebands and making it more difficult to fly with friends. Most video transmitters have
several options, generally at 25mW, 200mW and 600mW. 25mW is fantastic for indoor flying and racing events. In a good setup this will generally get you sufficient range to fly any FPV racing track. 200mW is a great all-around compromise and can get you enough range to do some serious exploring. 600mW is pretty overkill in most situations. I would generally avoid it unless you specifically need it for some reason.
Another important thing to consider when picking your power output is your local regulations. In Europe and many other populated countries around the globe, it is illegal to broadcast at power levels above 25mW. In other parts of the world, operating at higher power levels requires a special permit or license. We will touch on wireless broadcasting regulations in the future but in the meantime you should do your own research to determine what is applicable to you.
Wireless Band – There are several wireless bands that you can legally transmit video over. The most popular of these are 5.8GHz, 2.4GHz and 1.3GHz. In practicality, however, you will almost certainly end up using a VTX that runs on the 5.8GHz band. This is because transmissions on a lower frequency have the tendency to lower the signal quality of transmissions on higher frequencies. Since most of us use radio control transmitters that operate on the 2.4GHz band, we cannot use any bands at 2.4GHz or below – lest we want our control link to be weaker than our video link! Also – antenna size increases drastically on 2.4GHz and 1.3GHz – and no one wants a huge antenna hanging off of the back of their quad.
If you are building an FPV airplane or a larger quadcopter and have a radio control link that operates on 900MHz or 433MHz, it is worth considering the lower bands for video transmission. These lower frequencies will net you a much longer range and improved signal penetration through trees, structures and other blocks. A small downside is the fact that you will lose some video quality as lower frequency bands, particularly 1.3GHz, can carry less data than higher bands.
Channel Support – The wireless video spectrum can be broadcast across a broad swath of frequencies, or channels. When you buy a VTX, you will most likely see a “channel chart” that is shipped with it. This lists the channels that the VTX supports. Generally these channels are incrementally aligned with what is called a “Band” or grouping. In the past, different manufacturers only supported one band – so ImmersionRC transmitters only transmitted on the ImmersionRC band and Boscam only transmited on the Boscam band. This ensured that you had to buy a matching video receiver to go with your VTX. These days, things have gotten more open and most VTX’s support all of the bands out there. If you do decide to buy a VTX that only transmits on one band, you’ll want to double check that your video receiver (or goggles) can receive video on the band(s) that your video transmitter can transmit on.
The exception is the most important band – Raceband. This is a partitioning of the 5.8GHz spectrum that ensures optimum spacing between transmission frequencies so you can fly with up to 6 of your friends at once with almost no degradation of video quality at range. Many racing events require you to have a VTX capable of “talking” on Raceband. It also makes it easier to fly with friends because there is less “cross-talk” across the channels. For this reason, I do not recommend buying a VTX that does not operate on this band. All of our “suggested” VTX’s below support this band with the exception of the Crazepony, which is the super-cheap budget option.
“Compatibility” – One claim I’ve seen on many Video Transmitters is that they are “compatible with FatShark”. This is something you should really ignore. “Compatibility” is solely determined by the channel support of the video transmitter (see above). Don’t be duped into buying an inferior video transmitter because of claimed compatibility.
Size & Weight – It seems like this makes its way into every buyers guide – but for good reason. The size of your VTX determines how much spare space you have on you miniquad for other parts. Some of the particularly compact 210mm frames cannot even fit many VTX’s! Weight is always a concern when building miniquads.
Antenna Connector – VTX’s have a variety of different connector types available for you to choose from. The most important decision to be made here is between SMA connectors and RP-SMA connectors. Which one you choose should be determined by what antennae you currently have. If you have no antennas, choose SMA – it is by far the most popular standard. Don’t worry if you pick up the wrong one, however – you can buy converters to and from both types of connectors. Be aware that there is some performance loss when using converters, though, so it is better to pick the right connector on your VTX.
The other connector choice you will need to make is whether or not you want a pigtail cable or a board-mounted SMA. Then you will need to decide on a 90-degree SMA connector or a straight connector. Some VTX’s have SMA connectors that come out of the top of the board in lieu of a 90 degree connector. What you choose should be determined by how you intend to build your miniquad. When in doubt, look up some build logs for your frame and follow by example.
To learn more about miniquad antennas, check out our antenna buyer’s guide.
Digital or Analog – This isn’t really a choice right now, but with Connex’s announcement of their ProSight system in March 2016 and the announcement of a few other forthcoming digital systems, I believe we are the verge of an age of FPV where video may start getting transmitted over a digital link. Digital links confer a plethora of advantages, but for now are in short supply and cost a pretty penny.
Internal Microphone – Some video transmitters come with internal microphones installed. These VTX’s will allow you to hear your quad while flying by plugging set of headphones into your goggles. Some pro pilots swear by this – claiming it helps them hear the quad’s power level and identify the attitude better. I wouldn’t pay $10 for this feature but it is definitely “nice to have”.
Enclosure – Most video transmitters are bare PCBs with an antenna connector on one end wrapped in heat shrink. As long as these are kept within your frame, they are relatively safe. If you need your VTX to be more robust for some reason, you should consider a VTX with an aluminum or plastic enclosure. Keep in mind that enclosures add weight, however.
Voltage Tolerance – Most video transmitters run at 12V DC. Some, however, can tolerate up to 22V. However, I have read from several sources that these video transmitters have the propensity to blow when run directly from a 4-cell battery due to power surges caused by the ESCs when braking. I would recommend using an external regulator both to protect yourself from this and to clean up your power supply so as to avoid any video noise caused by your ESCs. That being the case, I generally do not pay attention to voltage tolerance on video transmitters. If you know for a fact that your VTX is going to tolerate 4S with no regulator, however, this could be an important factor in your purchasing decision.
It’s important to note that many VTX’s will not operate properly on 5V, requiring you to put two VRegs on your quad – one for the flight controller, another for the VTX. Lately, we’ve been seeing some transmitters come to market that can operate on 5V, meaning they will work with the voltage you are using for your flight controller. Just make sure your VReg can handle the current draw if you choose this option!
Channel Switching Mechanism – There are three popular ways to switch video transmitter channels on the market: DIP switches, which are changed using a small screwdriver while the VTX is powered off are the simplest and oldest. You will need to carry around a coded chart to determine which DIP switch configuration corresponds to which channel, however. Digital switchers with a button and a tiny display have become more popular lately. They work by pressing a switch to cycle through the channels when the VTX is on. They are a problem, however, when flying with friends since the act of changing the channels means you will actively be switching through channels which are probably being flown on. For this reason, these are often banned at racing clubs. The last variety which is still quite rare are video transmitters which can be programmed using an infrared remote. Often times these are “paired” to a proprietary receiver. They are great because they are both convenient and do not run the risk of walking over your friends’ FPV session.
One thing to note about the VTX market is that there are clones abound. If you find a VTX that looks exactly like a VTX on this list with the same claimed features but different packaging – chances are it is. In fact, I am not even sure if the VTX’s on this list are the original ones – the water is quite murky here. The point is, if you can find a good deal from a reputable vendor – buy it!
Betaflight Programming Support – This is a new feature that has been coming to market since Betaflight OSD allowed us to program our miniquads at the field with our transmitter. Two VTX’s – the ImmersionRC Tramp HV and the Team Blacksheep Unify – have a feature which allows you to change the VTX channel and transmit power from the flight controller. This is a really neat way of doing things at the field.
Popular Video Transmitters
The ProSight system was recently announced by Connex. It is the first extremely-low latency digital video link that is small enough to fit into most miniquads. We wrote an article on the benefits you will get from a digital link here. It is a bit pricey at $500, but for that you get the VTX, camera and receiver. Depending on what you are looking for, this value proposition may make sense. We have one on order and are excited to try it.
These video transmitters, sold by ReadymadeRC, are similar to the FX799 in features, except they have a nice aluminum casing with mounting brackets. I would use these in any quad that you want to “dress up”. They are also very cheap and the weight penalty for the aluminum case is surprisingly low.
ImmersionRC has been a long-time player on the VTX market. Their recently-released Tramp HV VTX is simply the best miniquad video transmitter on the market. It has the best signal quality, a great form factor, several safety factors designed in, can be powered off of battery power, interacts with Betaflight and is all around a fantastic VTX. This isn’t even mentioning the fact that it is programmable with a special wireless wand that many race directors are using these days to quickly assign VTX channels. Expect to see some clubs require the use of this VTX in the near future.
The problem is these things are eternally sold out. We really hope ImmersionRC picks up the ball someday soon so that it is easier to get our hands on it. For those looking for a similar VTX, checkout the TBS Unify (below)
FPV Ninjas has a full line of video transmitters that have some of the best value on the market, in our opinion. Our favorite is the pigtail model that matches the awesome lightness and form factor of the Hawkeye VTX line (see below) with a button-based channel changing system. They also carry an extremely lightweight and cheap ($20!) 40-channel receiver with a board-mounted antenna connector.
Hawkeye’s are an extremely popular micro-VTX. They are likely the smallest transmitter in this list. It is the only transmitter that would fit in my Bolt 210, for instance. They have a remote-mounted pigtail SMA cable and use DIP switches to change the channel. If you buy these, make sure you get the one with Raceband (the one linked does) as many do not have it.
Lumenier has two video transmitters, the TX5G2 models are the older ones and are functionally equivalent to the FX799 model discussed above. The TX5GPro models are more interesting though. They seem to be built from the foundation of the FX799 with two improvements: a switch which controls RF broadcasting – which fixes the primary problem with button-based channel switching systems (see above), and a better onboard regulator to protect the VTX from voltage spikes.
Team Black Sheep (TBS) came out with the Unify video transmitter last year as part of an effort to finish up their Powercube flight stack – which now encompasses all of the electronics you typically find on a miniquad. The Unify is controllable through a button or through an interface with the Powercube OSD. It’s one of the smallest transmitters on this list, comparable in size to the Hawkeye. However, it has a really clever SMA connector on the end of the pigtail which has a built in flat plate to mount against. I really like this design, having broken Hawkeye antennae in the past due to sheering against the carbon fiber.
Power output is user adjustable between 25mW and 800mW – giving you a little extra power over most of the other players here if you need it. The TBS Unify can also interface with Betaflight with it’s SmartAudio feature, allowing you to program channel and transmit power through your OSD.
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