Most First Person View (FPV) aircraft have two cameras. One of those cameras is typically an action camera such as a GoPro or Mobius. Its job is to record the flight in unflinching high definition. The other camera is a small security-type camera which creates the video feed that is downlinked to the pilot's goggles or monitor. Although the latter cameras offer much less in the way of image quality, they work well for downlink because they adapt quickly to changing light conditions and provide very low signal latency. Today, we'll look at solutions to record video from those cameras.
When it comes time to share video of our FPV flights, we typically reach for the GoPro footage. After all, what's the point of schlepping around an extra camera if you're not going to utilize the hi-def footage that it collects? There are times, however, when you may want to record the downlinked video from your FPV camera as well.
Even with the help of a spotter who has eyes on your aircraft, a downed model can be difficult to locate. Being able to play back the final seconds of a flight from the aircraft's perspective can reveal vital clues to help find the missing model. Another purpose for recording your video stream is to troubleshoot or tweak the performance of a model. This is especially true if you use an On-Screen Display (OSD) to provide a data overlay on the video downlink. This allows you to have a dashboard that correlates performance data with each moment of the flight. Since it's recorded, you can analyze the data after the flight - without the real-time overhead of piloting.
A third rationale for recording your video stream is that it may be your only image source. There are a handful of ultra-small and lightweight FPV platforms that just don't have the capacity to carry a dedicated hi-def camera. The Blade 200QX, and FPV Nano QX are just two examples among many. Whatever these set-ups may lack in video quality, they more than make up for with versatility. It's perhaps the only way to record an FPV flight that takes place indoors!
In order to record downlinked video, you need two basic components: a receiver to snag the video signal, and a video recorder to save the footage. There are numerous ways to meet this requirement. You may even be able to use equipment that you have on hand.
For my first FPV recording rig, I utilized the 'Video Out' capability of my FPV goggles. Using a 4-conductor cable with 3.5mm male plugs, I fed the video signal from the goggles to a video camera that could record from a "Video In" source. Not all cameras have this capability. In fact, my only camera that would work was an inexpensive unit that was several years old.
With a 6-foot patch cord, I was able to place the camera in my hip pocket while wearing the goggles. For the most part, my jury-rigged recording setup worked just fine. I only ran into one problem, but it was significant enough to make me seek an alternate recording method.
It is not uncommon for an FPV signal to fade or have brief dropouts during normal operation. Such instances are usually so brief or insignificant that the pilot may not even notice. Regardless, the camera does notice. Whenever I had a video dropout when using the recording rig, the camera would stop recording and thereafter ignore the input signal. To correct it, I would have to navigate the camera's menu to reselect the video input as the desired source and begin recording again. I usually had someone available to man the camera while I continued flying, but the interrupted recording sessions were an annoyance.
A Better Way
Not all recording devices require an uninterrupted input signal. I probably could have found another recorder that would have alleviated my troubles. Since I was on the hunt for new equipment anyway, I decided to get something made specifically for FPV video recording. Some goggles have a built-in Digital Video Recorder (DVR). While that would technically work, it's an expensive way to go if you don't need goggles.
I went with the Lumenier DX800 ($150) from GetFPV. It is a monitor/DVR that also has a built-in 5.8GHz receiver. Since it contains both of the necessary components for recording a video downlink, the DX800 is a standalone device.
Not including the protruding antenna, the DX800 measures 130mm x 90mm x 18mm. Most of the footprint is occupied by the 5-inch LCD screen. The package includes a pair of connection cables, but they are unnecessary if you're recording 5.8GHz video signals. You'll also get a wall charger for the built-in 3200mAh battery.
The 5.8GHz band is very common for FPV video equipment. The DX800's 32-channel receiver should work with most 5.8GHz video transmitters. You can either have the unit scan the channels for a signal lock or scroll through the channels manually.
The bottom side of the device has a receptacle with ¼-20 threads so that it can be mounted on a standard tripod. This proved to be a handy feature. If the sun is out while using the DX800, it's a good idea to install the clip-on pop-out sun shade. The shade isn't a magic potion, but it works well enough to make the screen visible on bright days.
The face of the DX800 contains five buttons used to operate the unit. Their operation is intuitive. A switch on the side lets you choose between video, photo, and playback modes. On the same side is the slot for the required Micro-SD card (compatible with cards up to 32GB), as well as sockets for A/V signal input, A/V signal output, and USB.
Using the DX800
I charged the DX800 for several hours before the first use. There isn't an indicator to show the charge status. So, I periodically checked the battery by turning the unit on and reading the indicator on the screen. Once it was fully charged, I inserted a 4GB memory card.
There is a menu that allows you to set a number of different parameters. Most of them deal with personal preferences and the manual does a pretty good job of explaining the choices. So, I won't go into any detail here.
For my first use of the system, I fired up my Strider racing quad. I set the DX800 to scan the channels for the best signal. A handful of channels picked up the Strider's video signal to some degree. The channel ultimately selected by the DX800 jibed exactly with the output frequency of the Strider's video transmitter.
The Strider has an OSD which displays a handful of parameters. I was able to see the OSD components on the screen of the DX800. With the unit set at eye level on a standard tripod and the sun shade in place, I had no trouble seeing the screen to verify that things were working properly.
I initially used the included antenna, but I found that the signal reception would fade and the screen would show static whenever the Strider was close to the ground and more than about 100 feet away. The signal would improve if I climbed the quad a little higher. I later installed a circular-polarized antenna on the DX800. Now, the signal is solid as far away as I'm willing to fly the model.
The only problem that I've had thus far with the DX800 can be traced back to my failure to adequately read the included manual. When in video mode, you press the record button once to begin recording. Pressing record again does not stop recording…it merely pauses it. So when you press record a third time to resume recording, the new footage is tacked on to the original file. To stop recording and create a new file, you must press the escape button.
The main issue presented by the pause/stop nuance is that I was unable to change into photo mode while the recording was paused. Moving the mode switch had no noticeable effect. I could even resume recording video with the switch in photo mode. Once I figured out how to stop the recording process, the switch worked as I expected.
Video files are saved in .avi format and photos are .jpg. To move them to my computer, I plug in the DX800 using the included USB cable. I use the format function on the recorder to wipe the memory card.
If you're going to fly FPV, you'll eventually find good reason to record your video downlink. There are many ways to accomplish this, so take your pick. One of the easiest ways is to use a combination receiver/DVR like the Lumenier DX800. If you use a different arrangement, share details of your FPV recording rig in the comments below.