DJI modulation/protocol

Any info on what protocol/modulation do DJI drones use ?

I looked at it with SDR, out of curiosity, but I could not really figure out the answer.

Any info on that ? I searched the net very carefully but found nothing.

DJI seems to be really protecting its technology.

Even the radio chips are covered with tar so that the hardware cannot be reverse engineered, model number cannot be discerned.

Any idea/knowledge on what radio chips DJI might use ?

Thanks for info!

I can add that the 5.8Ghz Variant (Phantom 2 Vision / Vision Plus) most propably uses a BK5811,
as one can see clearly the Beken logo on the RF chip in FCC Documents ("internal photos.pdf").
5.8G Protocol is unknown DJI custom, to best of my knowledge,
but sniffing data should be relative easy thanks to the extra board for RF.

Hmm, that is interesting, thanks !

I has removed the tar what is on the chip.
The radio chip is ML2730DM ,the MCU is LPC1735FET100,and it hava a CPLD is 5M240Z,I don't know why it have a CPLD...
Here is some info：http://bbs.5imx.com/forum.php?mod=viewthread&tid=1170033

Highly probable it's Futaba FASST, only they used these chips in their FASST line.

True, the 2.4G Phantom model with two receiver antennas are using Futaba FASST protocol.
Green (upgraded Phantom 1) or black PCB (Phantom 2) makes no difference.
You can bind using a compatible Futaba remote control (not able to verify that, but its commonly said on DJI boards I read).