DJI Digital HD FPV System


10 Oct
10Oct

For years, FPV pilots around the world have used analog video transmission systems to achieve immersion while flying.  For us the technology is everything the hobby is built around, granting us the bird’s eye view of the world around us. The analog system is reliable, effective, and cost efficient, the trifecta for FPV pilots everywhere.  HD video transmission systems have been a pipe dream that many have requested and chased after, and while there have been some forays into the technology, it never quite met the standards of the FPV community…..  Until now.


DJI Digital HD FPV-Title-Image

Enter the DJI Digital HD FPV System

The DJI Digtial HD FPV System consists of three separate components; the goggles, the air unit, and transmitter that all work together seamlessly to bring pilots the most immersive experience that FPV can offer to date.  Let’s take a look at each of the components on the surface level.

DJI Digital HD FPV Goggles

DJI Digital HD FPV Goggles

The goggles have a futuristic look with four antennas protruding from the corners.  There are non-ratcheted IPD adjustment sliders on the underside, however when put in place, they stay very well.  There are two buttons on the left temple of the unit, to cycle the channels up and down.  Underneath the temple is a USB-C port and a MicroSD slot.  The right temple buttons are on the top of the unit, and consist of a five-way joystick for navigating the menu, a cancel button, and a record button.  Under the temple is the barrel plug port as well as a headphone port.

DJI Digital HD FPV Air Unit

DJI Digital HD FPV - Air Unit

The air unit is the portion of the system that is installed into your aircraft (yes, this can be used in a fixed wing application as well).  It consists of four components linked together, the camera, the VTx / Rx unit and two antennas.  The VTX / Rx unit is encased in a aluminium housing that acts both as protection and as a heat sink.  There is a USB-C port on one side, and on the other, a Micro-SD card slot, status LED and microphone opening.  The antennas attach via MMCX connectors, allowing for removal or replacement if necessary.

DJI FPV Remote Controller

DJI HD FPV System - Transmitter

While seemingly basic, the DJI FPV Remote Controller contains everything needed to operate a multirotor, and a good chunk of fixed wing aircraft.  It sports two folding antennas, four 3-way switches, a ratcheting scroll when and a button on the right shoulder, and a momentary wheel and record button on the left shoulder.  The sticks are adjustable for both practitioners of both pinch and thumb methods.  There is a USB-C port on the bottom of the transmitter as well as a simulator PPM port.



DJI Digital HD FPV-Glasses

Initial Impressions

DJI Digital HD FPV Goggles

Asthetics

My first look at the DJI Digital HD FPV Goggles came from the the posts on social media.  When they were first released, from a design standpoint, they had a unique look that reminded me of a fighter pilot’s headgear.  However, did look a little bulky, especially compared with some of the current goggles on the market such as the prolific Fat Sharks.  When they arrived and I had a chance to try them on, that was especially true.  However, they don’t feel unbalanced on the head.  The design of the head band (even through I don’t especially like the over-the-top band) helps distribute the weight well.  Not having the battery on the side or back of the head strap but instead in your pocket, connected via the power cable really helps maintain the balance of the headset.

Ergonomics

The foam is attached to the goggles via velcro and is very comfortable.  It is shaped relatively well to create a decent light seal around the face.  However, my face is oval shaped and with that, I did experience some light leak issues around nose cut out and from the area around the temples.  That same area at the temples has room for the ear pieces of a user with corrective lenses.  While I normally wear contacts, I did use the goggles with my glasses just to check viability, and while the goggles did press slightly on my glasses, they were completely usable.

Interpupillary distance (IPD) adjustments are done via sliders on the bottom of the goggles.  While the IPD range on the DJI Digital HD FPV Goggles may not suit everyone, they are 1mm wider in both directions then the Fat Shark models.  Also, you can compensate digitally by reducing the screen display size within the menu of the goggles.

The buttons are in easy to remember locations and seem intuitive (or at least somewhat mirror locations on other goggle models).  Channel buttons are on the left temple, while menu navigation and record buttons are on the top right brow.  The Micro SD card inserts on the bottom left while power and headphones connect on the bottom right.  There is no power button on the goggles, but it’s easy enough to break the connection at the XT-60 connector between the cable and the battery so as not to stress the barrel connector.

The headband is comfortable to wear; however the over-the-top band is not really my thing.  I wrap up the band around the harness at the back of the head, and the goggles sit secure without it.  The straps are all adjustable via velcro tabs.

Electronics

The DJI Digital HD FPV System operates on a low latency, high resolution, & long range system.  Through the goggles, you see a 720p / 120fps image sent from the air unit, and can be recorded by the on-board DVR.  There are two screens in the goggles, one for each eye, similar to many of the other goggles on the market, with each screen having a 1440 x 810 resolution.  There is an built in transmitter as well in the goggles, which allows them to communicate with both the air unit and the transmitter, creating a closed loop control system.

The power system is setup to take anywhere from 2s-4s batteries, with 4s being the recommended voltage from DJI.  Also built in are image processing software that takes the incoming video and provides a whole suite of color modes, presets, and other options to adjust the image to the flying situation.

DJI Digital HD FPV-Air-Unit
DJI Digital HD FPV-Air-Unit-2

DJI Digital HD FPV Air Unit

Design

The size of the air unit is probably the biggest issue on the minds of pilots.  Adding 14.4mm to your stack height might seem a little much, but consider what’s resides in that aluminium shell.  Inside, you will find 3 components, the VTx, the Rx, and a DVR unit.  Now if you’re not running with the DJI FPV Remote Controller, that gives you one unnecessary component, however the other two are quality components and the heat sink is absolutely necessary when running the VTx at 700mW.

The camera is proprietary and according to DJI, is the only one that will work (at this point).  It fits in the micro category, however it is a little over 1mm wider than standard micros, and may need custom mounts to fit into existing frames.  Nothing a little 3D design and printing can’t handle.  It is replaceable if damaged in a crash, but does come in at $59.00 so it is quite on the pricey side.  DJI does provide schematics for replacement as well, which I will include links to at the end of the article.

The antennas connect via MMCX and as there are two of them, again they might require some custom 3D prints to mount effectively (and safely) on your aircraft.  Standard polarization on the DJI system is Left-Hand Circular Polarized (LHCP).  If you decide to go with another type of antenna, such as the Lumenier AXII antennas, either get LHCP or get a complete matching RHCP set for the goggles and air unit.

Electronics

The DJI Digital HD FPV Air Unit (say that five times, fast), hooks up via a 3-in-1 wire harness, which powers all the components inside.  The air unit can transmit at either 25mW or 700mW, which is strange there is no in between power levels.  It also has a built in power limiter, which will lower the power consumption when the motors aren’t spinning.  It will also kick in when the temperature gets too high, lowering the power output to protect the electronics.

The air unit has a MicroSD card slot in the side, through which you can record your flights, much as you would through a GoPro or a RunCam Split.  There is also an on-board microphone to record and transmit audio information, which can be listened to via the headphone port on the goggles.

Overall, depending on the popularity of the DJI Digital HD system, the size of the unit might reverse or slow down some of the trend toward smaller and more slammed aircraft, so as to fit the unit.  Some or most frames might be able to be modified simply with taller stand-offs, so don’t shy away just for the size.  The DJI Digital HD FPV Air Unit packs a punch in that housing.

DJI Digital HD FPV-Remote

DJI FPV Remote Controller

Design

First off, really? Remote Controller?  Can we just call it a transmitter?  Rant over.  Moving on, the DJI FPV “Transmitter” really does seem like an over simplistic unit, but really it does have just about everything needed to run a multirotor or simple fixed wing aircraft.  Not only that, but it boasts a 4km control range, same as the goggle / air unit combo.  The antennas walk a fine line of feeling sturdy, yet somehow fragile, but being able to fold them across the top of the transmitter helps me feel a little more secure in their safety.

On the left shoulder are two 3-way switches, a momentary scroll wheel, and a record button.  The right shoulder has two more 3-way switches, a ratcheted scroll wheel that also functions as a button, and a back button.  The switches can all be setup to do different things in both Betaflight and in the OSD of the goggles.  On the face are the C-Button (custom button) that can be setup as well in the OSD, and the power button.

The scroll wheel on the left shoulder cycles through screen presets to optimize your view.  The scroll wheel on the right shoulder is used to navigate the menu options for the goggles, and is a lot more intuitive to use as opposed to the goggle buttons.  To turn the unit on or off require a short press and then a long press of the power button.  A single short press with display the battery level on the LED’s across the bottom.

The one complaint I do have here is that the finish on the remote is a matte black, and does seem to show scuffing relatively easily.

Ergonomics

The DJI FPV Remote Controller (transmitter), looks boxy, and it feels boxy, however everything is well within reach whether you pinch or thumb those sticks.  The sticks themselves are adjustable, both in height, and in tension.  By removing the battery from the bay, the user gains access to two ports with screws that allow you to change from Mode 1 to Mode 2, as well as add or remove the ratcheting in the throttle.  Along the sides of the battery bay cover where the rubber grips start, you can peel back the rubber (don’t worry, its not glued down, just held in place by rubber plugs), and gain access to the tension adjustments for the gimbals.

The battery pack has a whopping 4920 mAh capacity, and is charged via the USB-C port on the bottom of the controller.  Expect the battery to last a LONG while on this transmitter.  While the unit itself is heavy due to the battery, with a lanyard attached it has great balance, relieving hand stress from having to hold on tight.

DJI Digital HD FPV System - Combo

Pre-Flight Experience

Before we get into how great the experience is flying with the DJI Digtial HD FPV System, let’s take a moment to talk about what the pre-flight is like.  I feel it’s important to test the system out on the bench, learn what options are available to you, as inevitably, this will make your flying that much easier!

Powering the goggles on for the first time without the air unit powered up gives access to basic functions.  When there is no signal detected from the air unit, a black “DJI” screen persists within the goggles, but you can enter the menu system from there and explore a tiny bit.  Most of the options will be grayed out, but it will allow you to get familiar with where everything is.  You will also notice that a fan powers up and stays on to keep both the electronics cool, as well as prevent fogging via the vents on the inside of the goggles.

From here, follow the instructions to pair up all your devices, and a whole new host of options will be available to you.  Everything from setting the transmit power, DVR recording modes, image processing, and remote calibration are available.

Key Items to Note:

  • Make some time at the beginning of your flight session to adjust the color settings if you are going to be recording.
  • If you have installed a MicroSD into both the goggles and the air unit, you can select which one you want to record from, or both.
    • You can also set the resolution and fps of your recordings.
  • There are two modes for getting video from the air unit to the goggles, Low Latency and High Quality.
  • You can adjust your flight controller settings directly from the goggle menu!  Awesome!
  • “Focus Mode” at first seems like it doesn’t do a whole lot, but it does focus getting you the most information in the area around the center of the screen, sacrificing the edge detail.  This could lend itself to racing by keeping latency down due to less data transmitted.
  • VTx transmission power is under “Device Info”.
  • You can perform PID adjustment directly from the goggles, just as you would through Betaflight OSD.

Remember, the system has depth to it.  Empower yourself by exploring all the options!


Flight with the DJI Digital HD FPV System

So, if you watched the video above, you can start to feel the difference in flying with the DJI Digital HD FPV System.  Views through the goggles are crisp and clean, giving the pilot views that until now were unheard of.  The level of immersion goes up, and some of the feelings of motion sickness might start to creep back up from the early days of FPV flight!

Gone are the days of static breaking up your screen!  In fact the only way that I could get static was to put the system in 25mW mode and force the multirotor out to the edges of the park, which even then there was some good distance before I started getting pixelation.

Why is the Air Unit so Large?

Here is where the effort that DJI has gone through in development of the DJI Digital HD FPV Air Unit comes through.  Let’s look at all it does during a flight.

  • First, it takes all the commands from the transmitter and relays those to the flight controller.
    • This includes PID adjustments as well.
  • Second, it takes the audio / video coming in from the camera and does two things with it:
    • Takes the raw video and sends it directly to the MicroSD card for HD recording.
    • Compresses the raw video to eliminate as much latency as possible and sends it via the VTx out to the goggles.
  • Third, the air unit also relays data about the aircraft (voltage, memory card usage, etc) and sends that back to the goggles.
  • Fourth, the air unit conducts image processing in accordance with the settings on the goggles, and applies that (sometimes on the fly through the profiles) so that the image being recorded by both the air unit and the goggles is optimal.

Think about all that!  It’s a busy little component!  It’s no wonder it’s as large as it is.  Also keep in mind that the aluminum casing gets quite hot during flight.  It wasn’t just one time that I made the mistake of picking the multirotor up by the body and inadvertently felt the heat put off by the air unit.

Items to Watch Out For

One downside to the DJI Digital HD FPV System is the audio.  It comes through completely tinny, and has no depth of range to it such as you would get from a GoPro or similar action camera.  It’s good for headphones if you wear them during flight, but beyond that it was completely unusable.

Second, the DJI Digital HD FPV Air Unit is power hungry.  There were a few times while flying with it that I noticed my battery was getting to the landing point, and by the time I made it back at a gentle cruise, my battery was well beyond where I would normally land it.  I did have to start coming back early on my subsequent packs to ensure I didn’t damage a battery.

Post Flight Information

The experience with the DJI DIgital HD FPV System doesn’t end after you land.  In fact there’s a little more to the system once you get the footage back to your computer.  Both the goggles and the air unit write the video in .mp4 format with H.264 encoding.  One small but exquisite feature are the file names the individual units give their video files.

DJI Digital HD FPV-System-File-Names

As you can see, the files from the goggles have the “DJIG” prefix, while the files from the air unit have the “DJIU” prefix.  This will help in distinguishing between the files if you toss them in the same folder on your hard drive.

Also visible here is the differences in files sizes between the two components.  The air unit files are significantly bigger (upwards of 50%) than those from the goggles.  This is due to the raw nature vs. compression factor.  Also, keep in mind that the video from the goggles comes in at 720p while you can select between 1080p and 720p from the air unit.

While we’re talking about video files, I would like note that I did have two files from the air unit corrupt.  I would highly recommend stopping the recording before unplugging the battery.  Hopefully this is something that DJI can address in a future firmware.

The Good and the Bad

Pros

  • Excellent HD image through the goggles allow for deeper immersion into the FPV universe.
  • Components work with each other seamlessly.
  • DVR capability from both the goggles and the air unit, giving you plenty of options to capture your flights.
  • Wide power range for air unit, simplifies adding it to your setup.
  • PID adjustment right from the goggles keep you tuning as you go.
  • Image processing depth give the user options for days.
  • Mimics what pilots have been using, keeping the learning curve shallow.

Cons

  • Goggles are bulky, making them harder to transport.
  • Air unit is large, which can make adding it to existing builds challenging.
  • Air unit gets extremely hot, be careful when picking up your aircraft after a flight.
  • Limited OSD on the goggles.  Give you information you need, but leaves some of it off the table, such a mAh used, crosshair, or GPS information.
  • Finish on the remote and goggles shows scuffs somewhat easily.
  • Air Unit is power hungry.  Watch your flight length.
  • Microphone is less than desirable for flight video quality.

Final Thoughts

Is the DJI Digital HD System a game changer?  Absolutely.  It brings the immersion pilots crave to a whole new level, and then breaks the level itself.  To have a system in hand that is comparable in price to a new, complete analog system, but shatters the boundaries we have had around us in one fell swoop, DJI has done something remarkable here.

Are there some issues?  Sure, but they aren’t a deal breaker.  And the future is bright for this technology now that the barrier has been broken.  Look for future offerings in HD FPV tech from some of your favorite brands.  It’s coming……


By Josh Cook

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