Most agree that digital video is the future of FPV. It offers a clearer picture with better detail along with better system range. However, racers have run into difficulty using the DJI digital FPV system; the most prevalent on the market. In my recent article Racing with DJI Digital FPV, I covered the basics and the challenges of using this system for racing. This article instead goes into more depth and detail about holding a race event. Erik Borra from Total Drone Xperience in the Netherlands and Kelvin Williamson from SELA FPVie in New Orleans are back on hand to discuss their strategy and approach for putting together an enjoyable race day for all.
GetFPV: What is your race control setup for events with DJI digital FPV?
Erik Borra (EB):
To run a race you typically need a timer and race management software. Additionally, a race director needs to be in charge of video power and frequency management. Also there need to be spotters for each pilot in a race, that make sure that a pilot takes all obstacles in a track correctly.
Currently I use Delta-5 hardware with 8-nodes in Ceberus Velvet’s flat case, running RotorHazard. For a training session with up to 12 pilots, I typically just use my phone to calibrate the settings and manage the race. The phone is connected to a Bluetooth speaker announcing lap times. Pilots connect to RotorHazard via my hotspot to inspect their times on the leaderboard. For bigger trainings or official races I typically use a Macbook Pro and connect it via Ethernet to RotorHazard. The Macbook is connected to an external screen or HDMI beamer for the display of heats and leaderboards. Audio is then typically connected to a PA.
Kelvin Williamson (KW):
Over the past few months I have been working hard to streamline our race control setup and track setup. We have our RotorHazard timing system protected in a hard case for the occasional quad strikes. We run Ethernet from the timing system to the race control trailer. Also, we have a 2.4GHz WiFi router in the trailer to broadcast the RotorHazard system so pilots can access their race data. I made a video for my pilots about how to remotely access the timer to review their results. Also there is a PA system integrated into the race trailer for announcements. We have gone from a 2 hour race day setup time with 3 people, to a 30–45 minute setup time with just 1 person.
GetFPV: What have you changed about your setup since you began including DJI digital FPV?
Even though I had a lot of experience with (tuning) the Immersion RC LapRF 8-way, I just couldn’t get it to reliably pick up lap times for DJI. It would typically miss one in four rounds, and missed lap times aren’t recoverable in LiveTime. Online, others seemed to have the same experience. I had heard that RotorHazard might be able to do it, so I picked up the Delta5 timer I had once built—but which did not work reliably indoors—installed RotorHazard, and was blown away by the Marshal function. This function allows you to inspect the RSSI graph for any pilot and adjust the values for which a lap is detected. The RSSI graph for DJI was really clearly pronounced, allowing me to easily set to proper tuning values and pick up each and every lap. After my enthusiasm about RotorHazard, which is also really precise in tracking analog, many of the other organizations in the Netherlands also built a RotorHazard timer (or reused their old Delta 5 hardware). It is so intuitive that I can often participate in races, whether there are 2 or 6 heats. (Make your quad ready for the next race before doing anything else though ;))
GetFPV: What special accommodations do you make for DJI digital FPV racing?
Make sure you know about frequency/channel management. If there are multiple DJI pilots, put them in the same heat. If there are only few, put in the effort to learn which DJI frequencies go well with analog frequencies. Typically it works fine to put analog on R1 and R2 and DJI on D6 and D7. We have run plenty of sessions like this without issue for analog. Make sure to never put an analog pilot on R6 when flying mixed heats, as it gets interference from DJI’s public channel (D8) whenever a DJI pilot plugs in his quad.
When running many DJI pilots, it is our experience that it works best if pilots that sit ‘next’ to each other are not on consecutive channels. So line up the pilots and attribute them in an order like the following: 8 – 1 – 6 – 4 – 2 – 5 – 3 – 7
Mixed heats work best when Raceband is on 25mw and DJI is on 200mw. Yes, I know Raceband pilots will stagger, but really it works best 🙂
DJI-only heats can easily be run on 500mw or 700mw, even (or maybe better yet) in high multipath environments. Also with 8 pilots at the same time. Racing with 8 pilots is awesome! When you have 8 DJI pilots, make sure that the one flying on D8 only plugs in when all the other 7 pilots are plugged in and locked on D1–D7. Then, plug in D8. It will work fine.
Shield your timer and put it in the corner of a gate at a 45 degree angle and pointing away from the rest of the track.
Spotting can be done through goggles. You really don’t need a lot of expensive smart controllers.
- RotorHazard for timing.
- Keep all DJI pilots separated 5 meters from other DJI pilots and analog pilots in the pits.
- Try to run separate DJI heats when possible.
- If you must mix DJI with analog, Limit to 4 pilots in a heat to keep the airwaves less congested.
- When mixing DJI and Analog in a heat, use Frequency Channels R1, R2, F2, F4, D6, D7.
- Facing the timer down over the start gate will help prevent false triggers from the goggles. I have seen false triggers when the timer was angled 45 degrees at the start gate and subsequently pointing towards pilots in the pits. This is only an issue when the pits are too close to the start gate.
- All pilots, Digital and analog @25mw output power.These steps have been working well for smaller club level races with around 15 pilots, but could work equally as well at larger events.
GetFPV: What else is important for running a successful race day?
Be welcoming to everybody that likes to fly.
Always take complaints seriously, even if pilots whine. Make sure to have an ImmersionRC power meter to check VTx output power, and to have a screen that can be tuned in to one of the Raceband channels. If there are parallel white lines, that channel interferes with DJI. DJI has less problems with interference, although the image may turn ‘blocky’.
There are a few things I do to make the for a smoother race. First I post up the race within the MultiGP website. I always state the track layout and the scoring format for the event. I use a 3d printed track design kit to generate the basic course. I post a picture of the layout so pilots can easily view it. This saves a ton of time on race day. We don’t need to do track walks or explain the course layout over again for pilots arriving late.
The night before the race I generate all the practice heats in RotorHazard, check MultiGP to get a rough idea of who signed up for the race, then I begin arranging pilots in heats of 3 or 4, leaving a few slots open for pilots that show up on race day without signing up.
I keep several custom frequency profiles saved in RotorHazard. Analog only, DJI only, and mixed. In addition, classes are setup as follows:
- Open practice – (Infinite time. Times announced by frequency/ch)
- Controlled practice (Timed race. Results not saved. Times announced by pilots handle)
- Bonus Rounds
This allows me to quickly get heats set up. On race day pilots log into the RotorHazard server with their smart devices to see a full overview of the event. They can see the video channel and what heat they’re in.
I run open practice right after the course is setup. I like to give the pilots that showed up early to help set up an opportunity for some extra flight time.
We run a few rounds of controlled practice before the Qualifying rounds. This gives pilots some stick time to get comfortable with the course. But most importantly gives me a chance to work out any video issues and any necessary calibration adjustments to the timer.
It takes more than clean video to run a smooth event. SELA FPVie helps keep pilots informed with a visual representation of the course.
Erik and Kelvin have slightly different approaches for making their events work. This surely comes down to each group’s unique needs of their pilots, racing environment, culture, and more—so it’s likely that setting up your own group will mean making some adjustments as well. But their work provides an excellent starting point for anyone looking to get on board with this new technology. You can join Erik, Kelvin, and 200 other DJI digital FPV racing enthusiasts on the DJI FPV GP Racing Facebook Group to ask questions and figure out what works best for your unique situation. It’s also a great place to keep up on parts selections, race formats, or just to watch spectacular HD footage from race events. And if you’re already racing DJI digital FPV, please share your experience!