Once my Spark and the RC are linked, the RC network appears on iPhone devices but not in Android phones. I tried with 2 iPhones and 3 different Androids phones.
Any ideas?
I used the OTG cable to connect the RC to my Android phone and at some point it stoped working, so I started to use directly the WIFI option. After few days, this option is not possible either.
If I just turn on the RC, it is visible by an Android phone, but once the RC is linked to the Spark, then that network disappears for the Android phones but not to iPhones.
Did this happened to anyone? Any clues? Is ther a way to reset the RC or something?

Press and hold the power button for 9 seconds, then you'll hear several beeps, then the WiFi will be reset.  Are the RC and drone both up to date? What Android devices are you using?

There are several threads talking about this... it seems is about european regulation and how the RC switch the wifi frequency for the smartphone when the wifi frequency for the drone is changed:
https://forum.dji.com/thread-108416-1-1.html

So it's a very common issue
the easiest way to solve this is to use a OTG cable... It should be supported officially...

I tried myself with an Ipad of a friend, when using the Spark with a RC (connected with WiFi), the Spark at power-on connects to 5.8 GHz network, and the RC wireless is available both for Android and iOS. When you try and switch the frequency to 2.4 GHz, the wifi connection of the RC disappears from Android devices and is available only on iOS devices.

A user posted the following in this thread: https://forum.dji.com/thread-108416-1-1.html
My current knowledge:
If the RC to Spark connection is set to 5,8, the connection RC to phone is 2,4.
If the RC to Spark is switched to 2,4, the connection RC to phone should be 5,8.
The 5,8 channels used are not allowed in CE regions because of regulations, which Android respects, Apple does not.
That would explain all the behavior.

DJI should absolutely do something about this, it's pretty bad to say that the RC has a maximum range of 2km when in Europe is only 0.3 (6-7 times lower!!!). The 2.4 GHz has better range (I tested it myself when my OTG connection was still working), but it's not available in Europe without an Apple device or by the use of the OTG cable (an unsupported function - that in fact is still kind of buggy even if greatly boosts the video transmission quality - when it works).

FrenchiVIII Posted at 2017-8-19 11:55
I tried myself with an Ipad of a friend, when using the Spark with a RC (connected with WiFi), the Spark at power-on connects to 5.8 GHz network, and the RC wireless is available both for Android and iOS. When you try and switch the frequency to 2.4 GHz, the wifi connection of the RC disappears from Android devices and is available only on iOS devices.

A user posted the following in this thread: https://forum.dji.com/thread-108416-1-1.html

Hi
I am the user who posted the thread mentioned, but confused as my wifes android samsung galaxy tab A10 works and the Rc wifi does not disappear and can connect to 2.4 without OTG but my android Samsung S6 and Nexus 7 loses the rc wifi in the list and therefore can not connect to 2.4 unless i use OTG
so it cant be android device problem as some android devices work and some dont

Thats even more weird, I've tried multiple android devices without luck...

xtro Posted at 2017-8-20 00:05
In 5.8 dji uses channels 145 to 165 that do not work on android in CE

[view_image]

So, given that the OTG is not supported and the RC uses both frequencies in WiFi (one for the smartphone and one for the aircraft), there's no officially supported way to use Spark legally in Europe (with the RC)... That's ilarious!

FrenchiVIII Posted at 2017-8-19 13:09
Thats even more weird, I've tried multiple android devices without luck...

Samsung S8 is ok with 5.8 GHz.

xtro Posted at 2017-8-20 00:05
In 5.8 dji uses channels 145 to 165 that do not work on android in CE

[view_image]

These channels are made for "low power" applications. This is why in CE mode the power are reduced when compared wit FCC. As these channels are not fully normal channels, android phones (except Samsung S8 for sure) don't see the need to use them where IOS devices accept them.

The only solution to this problem is for DJI to make OTG a supported feature or bye one of the very costly devices such as an ipad mini 4, only thing is that makes this more expensive than a Mavic pro !!!!
Oh and if your thinking you can ship something from the states, think again. These device know where they are and set themselves accordingly

Thank you very much guys for your answer. You helped me to resolve it after so many hours trying one thing or another.
As I was travelling in the Balkan region going in and out from/to countries that belong and don't belong to the EU, it was a big mess for my android phone. In some countries working and in some not. I borrowed an iPhone and changed the setting to 5.8Ghz and now all working fine until I get a new OTG cable, because the one I got only worked for few days (i guess because some crappy quaility in the connection port).

Same problem here. Yesterday i updated Spark and RC and DJI GO app to latest firmware and versions.
I am using Android phone (Xiaomi Redmi 3) with using RC (via WiFi) it's almost all the time switching between 2.4 and 5.8 GHz and get only 100-150 meters of distance. With constantly drop of Image Transmision Signal and frozen RC commands. (First image)


When using OTG cable and 2.4Ghz i get promised 500 meters distance and 300 meters altitude. (I probably could get further and higher). Very little lag and drop of signal. As image show below.


Today i am going to test this again and try to use all features and gestures, cause i readed that some have issues with them while using OTG cable.