I am totally new to this arena. First Drone and not been outdoors yet. I have however flown indoors trying to cut my teeth on simple manoevres. I have a Samsung Galaxy Note 3 on Android version 5 (Lollipop) It wont upgrade to a higher version of Android without hacking it.
Despite this phone being on DJI's approved list, i have found that it will be unuseable as a screen. it has lag of 3 secs + and terrible image pixelation / lost image altogether. All other apps are closed and it fails to improve.
After a lot of reading up on here i am almost at the point where it seems IOS is the way forward and my solution is to buy an Ipad Mini 2 WIFi only... Is this a realistic route?

Please ensure that it is not caused by the environment and I would recommend you enter the wifi-setting and fly in a place when most channels are green. Also, please do not wear bluetooth device. You can also clean the cache and run DJI GO 4 only for further check.

The latest version of DJI Go 4 is necessary only for the Mavic 2, you can try earlier versions if you are only flying the Spark. DJI Go 4 is a mammoth and in my opinion it should be split, an app for flying and one for the rest of the things it does.  

The recommended list is old and DJI refuses to update it. Your realistic route should be an iPad Mini 4 WiFi for best results.

Conclusion was to buy an ipad mini 2. Works perfectly!

Duncdude Posted at 2018-10-19 03:59
Conclusion was to buy an ipad mini 2. Works perfectly!

Thanks for letting us know what your solution was. Very important and helpful when people post their final results/solutions when having troubles. We can all learn then!