Experience with 2.4GHz Remote Controller Interference or Conflicts?

[Phil Tuggle]

Being excited to have my Part 107 Remote Pilot exam passed and Certificate applied-for, I was just scouting a downtown location in a neighboring city where a company wants to hire me to shoot their property. There were no significant issues with the location or with pedestrian and vehicular traffic close by...BUT...

I pulled out my trusty WiFi Explorer phone app and discovered a gizzilion (oh, AT LEAST that many!) wifi signals in the immediate area. These were spread across the whole range of 2.4GHz, from 2.412 to 2.484, with a few sneakers coming in and out. There are lots of medical offices in the area and no doubt they communicate all the time, though it was only a little after 8 a.m.

Okay, so I use a Phantom 3 Advanced and the user manual states on page 55 that my remote controller operates at 2.400 to 2.483GHz. As you can imagine, I am very hesitant to do this photo job. No way will I risk loss of control and whatever follows. I have never had a flyaway and don't want to begin that.

Here is the Question: Are these concerns well founded? That is, is radio interference really likely and predictable?

 

[N017RW]

The more 'congestion' the lower your signal to noise (other signals) ratio is.
This typically reduces range.

The ISM Band is unlicensed and you will run into this often in populated areas. It is required that each device 'accept' this interference. Your Phantom is designed to RTH upon loss of signal (interference acceptance) so a 'fly away' is unlikely for this type of problem.
However even in quieter locations other failure modes are possible which may create other hazards.

Good that you are investigating such things.

 

[Phil Tuggle]

N017RW, post: ...Your Phantom is designed to RTH upon loss of signal (interference acceptance) so a 'fly away' is unlikely for this type of problem.

Curious then, does the remote controller have some kind of code or handshake with the aircraft? I mean, if the P3 loses THE UNIQUE signal from my controller, it cannot become confused into thinking some other wifi is re-connected, Can it? This would mean the controller is not only the proper frequency, but also transmits some kind of "It's Me!" Code? Probably a dumb question.

 

[N017RW]

You've got it.
It is called 'binding'. The Tx & Rx are introduced to each other. A unique transmitted code is used by the receiver to recognize the commands from the bound transmitter.

 

[N017RW]

I must also mention you need good GPS reception for RTH to function.
Without GPS there are other scenarios which would come into play.

 

[Phil Tuggle]

That really clarifies things for me; not nearly as edgy a risk then as I thought. I do indeed use the GPS and have the RTH function ready to go on its own or by input. So, tell me this - is the phenomena of interference (that still could happen) simply a matter of drowning out my remote controller signals in a sea of signals? ...Like me trying to listen to one radio when 10 are blasting away? Or...really not, since I would not actually "hear" the other 9 radios; they would simply weaken what I could hear? TERRIBLE analogy - just trying to envision what is happening.

 

[With The Birds]

That really clarifies things for me; not nearly as edgy a risk then as I thought. I do indeed use the GPS and have the RTH function ready to go on its own or by input. So, tell me this - is the phenomena of interference (that still could happen) simply a matter of drowning out my remote controller signals in a sea of signals? ...Like me trying to listen to one radio when 10 are blasting away? Or...really not, since I would not actually "hear" the other 9 radios; they would simply weaken what I could hear? TERRIBLE analogy - just trying to envision what is happening.

Ignoring the numerous potential non wifi sources of interference if we consider the other access points you identified we are dealing with co channel and adjacent channel interference. Given your phantom follows the same rules as the other 802.11 devices it will work cooperatively with
them to share bandwidth. Lightbridge, while proprietary and awesome, is almost certainly nothing more than a very nicely developed implementiation of the wifibroadcast protocol (part of the wifi standards and demonstrated beautifully by the FPV open source users with raspberry pi's on their AC's. Same or better range than lightbridge with equal or lower latency and some doing 1080p),

You may have less range, you may see dropped frames and other video glitches, you shouldn't expect to completely loose connection though and the medical centre AP won't hijac your AC.

 

[Phil Tuggle]

GOT IT! Thank you, my friends, very much!