In my opinion OTG connection for Spark should be available. Maybe not as primary way to connect your device to RC (instead of wifi), but as emergency. Everyone wants to just extend the range of Spark. I have another experiences and as far as I know no one is aware of this even if it happens to him or did not share yet.
I have activated my Spark (fly more combo) and did few flights in Poland. Of course it took me some time to update everything. I connected my phone (samsung galaxy s7) to RC and everything was working fine. Then I travelled with my spark to Serbia. *Serbia has very strict UAV rules but this is not the point.
I turned on everything and DJI GO4 app informed me that I'm flying in different region and it will amend wifi settings to comply with local regulations. After that I lost wifi connection between s7 and controller. I was able to connect it together but I kept loosing it after turning on the Spark.
Then I tried OTG cable. I had v 4.2.18 of app so it was working but with issues (like problems with telemetry). I sorted it out by downgrading the app to v 4.2.15 and disabling auto update.
However controller is still charging my phone like powerbank.
I found maybe two topics of Serbian guys witch had problems with wifi connection between phone and controllers of their Sparks. Finally they were using OTG but they did not sort out why it is not working. (I was lucky that I activated my Spark in Poland).
I did some research. Spent few days for trying all different combinations of apps versions and drone softwares.
That is what I found out:
I had connection between Spark and Controller but my phone (s7 which is on the DJI supported devices list did not see controller's wifi). I tried with my friend's IPhone 5 and iPhone saw it and everything worked fine via wifi. Spark was connected to RC by 2.4GHz and RC to iPhone by 5.8GHz on channel from the upper border of band 161 or something like that. I installed some wifi analyzer app on my s7 and I found plenty of 2.4GHz networks and some 5GHz but up to 5.4 or 5.6 GHz (spark RC network was still out of range of s7). I tried the same with my ultrabook and sparkRC was visibile for it. Then I took my Spark and Controler to mobile phone shop turned both on and checked some phones.
It turned out that:
-galaxy S7, S5neo, j3 do not see Spark RC's network on 5.8GHz.
-galaxy s8, s8+, j5, iPhone 5, 7 and 8 can see Spark RC's network on 5.8GHz
I contacted DJI support on facebook, they tried to help me but it was something new for them, I tried to change channels through iPhone 5 but it did not work for galaxy s7, looks like it is resetting do default after disconnecting phone.
Now I am in Belgium and settings has changed again so my wifi connection works again.
That is what DJI should do:
-remove samsung galaxy s7 from supported devices, or
-implement fully operational OTG support for
Spark, or
-update dji Spark Controller's software with automatic start on some lower frequency closer to 5GHz supported by all devices from supported list.
Sorry for quite long post. I hope that it will help someone.
Best regards
