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Comment by robinduckett

4 months ago

I'd love to see some analysis of their OTA transmission formats. Currently the DJI headsets must communicate with the drone somehow in order to receive the video stream - this means the headset is constantly transmitting to the drone and this can effect other people even on different frequencies flying drones and it makes spectating rather difficult (and racing in groups impossible, not that you would want to race DJI drones as the variable latency does not really lend itself to drone racing).

There is already some signal analysis done by those in the field on Youtube but an open source method to pull packets from transmitting drones and redisplay them without transmitting to the drone would be wonderful.

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robinduckett

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05  4 months ago

> can effect other people even on different frequencies flying drones and it makes spectating rather difficult (and racing in groups impossible,

It’s a solved problem, spectating is supported out of the box and frequency bands have been public for a long time.

Here’s a JB video with all you need to know to coexist with analog: [1] Here’s Oscar Liang’s frequency chart (updated for O3): [2]

[1] https://youtu.be/P0b99JDcUQs

[2] https://oscarliang.com/fpv-channels/

dji4321234  4 months ago

> pull packets from transmitting drones and redisplay them without transmitting to the drone

You can see what happens when you try this by putting DJI FPV Goggles in Audience Mode. It's horrible and not suitable for flying. The DJI link is fundamentally two-way and aggressively uses sounding and HARQ.

The solution to flying with DJI FPV users at your field is to not use Raceband 6 at all (DJI uses this for link negotiation), and otherwise look up the Raceband to DJI correlation chart and allocate separate channels as usual.