Major Interference was it my Mobile Hotspot?
1052 6 2020-12-28
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Bussty
First Officer
Flight distance : 320951 ft
New Zealand
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Yesterday I flew in a location in the country I have flown before without issue. But this time my drone disconnected many times once around 500-700m out.

I was flying using Dronelink and Lichi and both apps had a similiar disconnect issue.

Normally before any flight I load up DJI Fly incase I have to recalibrate compass etc yesterday when I switched on DJI Fly it said there was a Flysafe Database update required. (haven't had too many of those) so my phone doesn't have a SIM so I hotspotted to my other phone and updated the database, this actually took a while and I got a "Hot Drone" warning (it was a hot day). I quickly turned off the drone after the update (Does the flysafe update into the drone or just the phone?)

Not thinking I left the hotspot going and didnt turn off wifi or go into airplane mode on my drone phone.

So then I launched my dronelink mission it went fine then about 500m out just stopped and lost connection JJB flight log analyser showed major interference about this time.

I RTH'd the drone then launched using Litchi and it got partway through a 360 pano then stopped (twice)

This experience has prompted a few questions...

  • Does the Flysafe database update, update the drone or the phone or both? i.e do you need your drone on while updating the database?
  • Is a mobile phone active hotspot a likely culprit in causing the interference I experienced? Given I was in the country, have flown there fine before and from memory have never had the hotspot active previously.
  • What is the best policy? When flying my Mavic Mini should I have my drone phone on airplane mode and my normal phone off altogether?

Thanks in advance for any thoughts?



2020-12-28
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Geebax
Captain
Australia
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The answer is yes, the mobile hotspot could cause local reception problems, and also yes, it is best to fly with your mobile phone in airplane mode. WiFi link frequencies are in the same band as the aircraft and controller bands.
2020-12-28
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Bussty
First Officer
Flight distance : 320951 ft
New Zealand
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Geebax Posted at 12-28 18:43
The answer is yes, the mobile hotspot could cause local reception problems, and also yes, it is best to fly with your mobile phone in airplane mode. WiFi link frequencies are in the same band as the aircraft and controller bands.

Cheers might try and do some testing on this to see if I can reliably recreate fault with hotspot and more importantly  see if can make it fault free without!
2020-12-28
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DJI Stephen
DJI team
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Hello there Bussty. I am sorry for the trouble this has caused and thank you for reaching out. In addition to this post putting the mobile phone in Airplane mode while flying would lessen the interference like receiving calls and text messages while on flight. In It is not necessary to put your device in Airplane mode but please make sure there is no such calls/text message or any notification that will interrupt you when using your device while flying your DJI Mavic Mini. Thank you for your support and have a safe flight always.
2020-12-28
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Bussty
First Officer
Flight distance : 320951 ft
New Zealand
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Well that's pretty conclusive, I did some tests today in my back yard with the mini and when not in Airplane mode, with WIFI still on and Wifi Hot Spot on on my other phone, connection to the drone was almost impossible! Turning ON airplane mode, turning off wifi, turning OFF mobile hotspot on my other phone gave me solid connection. This also checked out very visibly on Airdata Flight Logs.

To be honest I should have been doing this religiously as part of my pre-flight check but from now on all communications to and from the drone phone will be shut down.

I was also quite surprised how strong the Hotspot Wifi signal is from my other phone when checked with WIFI Analyser (Android App) so it is no wonder this was causing issues.

So hopefully back to relatively interference free flying with the mini. I'm also thinking of getting some range extenders, not to extend the distance but maybe just increase reliability of signal a little.
2020-12-29
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DowntownRDB
Core User of DJI
Flight distance : 1722 ft
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United States
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Bussty Posted at 12-29 20:36
Well that's pretty conclusive, I did some tests today in my back yard with the mini and when not in Airplane mode, with WIFI still on and Wifi Hot Spot on on my other phone, connection to the drone was almost impossible! Turning ON airplane mode, turning off wifi, turning OFF mobile hotspot on my other phone gave me solid connection. This also checked out very visibly on Airdata Flight Logs.

To be honest I should have been doing this religiously as part of my pre-flight check but from now on all communications to and from the drone phone will be shut down.

Nice testing Bussty.  I also found out a year back to turn off my mobile wifi hotspot due to the interference it caused.  So like you I added that to my pre-flight checklist. No issues since.  

Glad you got it sorted out.  Happy New Year.
2020-12-30
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Bussty
First Officer
Flight distance : 320951 ft
New Zealand
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DowntownRDB Posted at 12-30 05:51
Nice testing Bussty.  I also found out a year back to turn off my mobile wifi hotspot due to the interference it caused.  So like you I added that to my pre-flight checklist. No issues since.  

Glad you got it sorted out.  Happy New Year.

Cheers Downtown and Happy NY to you too.

Yes there is so much to remember when flying a drone I think the checklist is a must. I have had my drone about  a year now and it amazes me I'm only really now fully starting to understand it's idiosyncrasies...  
2020-12-30
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