Recently, I have taken a little time to profile the RF systems for the Phantom 3 "Lightbridge" system. I have unlocked the application installed on my mobile device to be able to select all 32 Channels that Lightbridge offers. It should be noted that the channels outside the 2.4 Ghz unlicensed ISM band have been locked out by the more recent versions of the application to prevent illegal operation outside the ISM spectrum. Using a Rhode & Schwarz DDF007 receiver I was able to get a pretty good idea of how the system functions within the RF spectrum. The Phantom 3 Advanced and Professional seem to be using two separate RF link systems. One system for control of the aircraft which operates in the 2.4 Ghz ISM band (exclusively) for control uplink, using spread spectrum and another system that can operate anywhere from 2.28-2.6 Ghz which is a GFSK (Gaussian frequency-shift keying) digital video signal for downlink of the video image. Both uplink and downlink systems appear to be using MIMO (multi-in-multi-out) diversity antenna systems with an RF output power collectively at ~750 mw for each system. Below is a list of frequencies the GFSK video downlink system uses corresponding the the DJI "Channel" number. These are 10 Mhz wide channels with the center frequency being listed and 5 Mhz being occupied on either side of center. CH 1: 2.285 Ghz CH 2: 2.295 Ghz CH 3: 2.305 Ghz CH 4: 2.315 Ghz CH 5: 2.325 Ghz CH 6: 2.335 Ghz CH 7: 2.345 Ghz CH 8: 2.355 Ghz CH 9: 2.365 Ghz CH 10: 2.375 Ghz CH 11: 2.385 Ghz CH 12: 2.390 Ghz CH 13: 2.405 Ghz CH 14: 2.415 Ghz CH 15: 2.425 Ghz CH 16: 2.435 Ghz CH 17: 2.445 Ghz CH 18: 2.455 Ghz CH 19: 2.465 Ghz CH 20: 2.475 Ghz CH 21: 2.485 Ghz CH 22: 2.495 Ghz CH 23: 2.505 Ghz CH 24: 2.515 Ghz CH 25: 2.525 Ghz CH 26: 2.535 Ghz CH 27: 2.545 Ghz CH 28: 2.505 Ghz CH 29: 2.565 Ghz CH 30: 2.575 Ghz CH 31: 2.585 Ghz CH 32: 2.595 Ghz As you can see, many of these channels are clearly outside the 2.4 Ghz ISM band, which is why they are locked out of the application. I have attached some photos of the spectrum analysis of these systems. Image 23 Depicts the video downlink signal (10 Mhz wide peak)within the 2.4 Ghz ISM band with the controller FHSS signal peaks on either side. Image 09 Depicts the controller operating within the 2.4 ISM band on the left (spread spectrum) and the video downlink frequency (1o Mhz wide) operating above the 2.4 ISM band in one of the "upper channels" on the Lightbridge system. Image 16 Depicts the video signal operating just outside the 2.4 Ghz ISM spectrum with the controller occupying peaks spread across the 2.4 ISM band. Image 22 Depicts the controller signal hopping across the 2.4 Ghz ISM band with the video downlink channel not shown. Image 23 Depicts the video downlink operating inside with 2.4 Ghz ISM band along with the controller's frequency hopping activities.