Hello guys,
Hope you all are doing great!

First I'm gonna describe the setup I use:
Iphone 7 plus
OTG cable
Generic antenna boost
Always with the latest firmwares and app.

I've been flying in many locations but since day one I fly over a huge water reservoir next home, where I fly the most. It's a huge open space.
Usually at this spot the spark starts losing connection around 1 km and the video feedback is really laggy and grainy. It almost always forces RTH which I always cancel to keep flying.
Today I forgot to bring the OTG with me as I was too lazy to fetch it I decided to fly without. I gotta say it was waaaaay better without the OTG, the video feedback was flawless with a fast response and beautiful resolution. I actually was able to take the drone across the reservoir which is 1km alway from homepoint then go much further at 2.2km distance from home point. Without forced RTHs, almost no lag and with an astonishing video feedback.
Only at the 2.2km point I had minor video lags. I could go even further but for the safety sake I brought it back.

Maybe my OTG is not good enough?
Or maybe we don't need it at all?

Hi Brilhas maybe you didn't have Wifi Interference and you are on FCC Mode.

For example here in the OVER POPULATED Island of Malta, in every corner you will People on using their Wifis. Every corner you go you see Transmission Noise due to the Heavy Wifi Traffic and Usage there is. If you go in a Remote Site in a Place so Big like Brazil I don't think you will have any Problems.

In CE Mode the 5.8GHz is useless, Very Low Power. Thats why many suggest to use OTG here, so that the Connection between Spark and Remote will be 2.4GHz as it has a bit more power.

Hi, thanks for your feedback. As of the moment, OTG cable is not yet optimized for you to connect your phone to the RC, we would recommend using a Wi-Fi connection for the mean-time and avoid flying in a hazardous environment so that you could be able to maximize the usage of your spark.

Hi there, Kindly check this thread: https://forum.dji.com/thread-157768-1-1.html for updates about using OTG cable on spark using  Android device.

DJI Paladin Posted at 2018-7-19 05:07
Hi there, Kindly check this thread: https://forum.dji.com/thread-157768-1-1.html for updates about using OTG cable on spark using  Android device.

What about IOS? Iam a IOS user. Iphone 7 plus

I'm an IOS user and for what it's worth, I tried flying my Spark without the OTG cable in my front yard away from the house, away from concrete surfaces, bluetooth was disabled, etc., and the video lag was horrible. It also took longer than usual to establish a GPS lock (not sure why in this instance). I didn't feel safe flying because the lag was persistent, so I landed the Spark and tried another flight with the OTG cable, figuring that perhaps I was getting Wifi interference from the neighbors. The flight with the OTG cable was much smoother and I was able to get the photos I wanted. I compared the records of the two flights and saw a lot of "Downlink restored" messages on the first flight but no errors, fortunately. However, I've been on this board long enough to know that those can precede more serious connection issues people have experienced.

I've been able to fly the Spark in my neighborhood with no OTG cable and have been fine. But it is nice to have another option available.

Tervist Posted at 2018-7-19 09:22
I'm an IOS user and for what it's worth, I tried flying my Spark without the OTG cable in my front yard away from the house, away from concrete surfaces, bluetooth was disabled, etc., and the video lag was horrible. It also took longer than usual to establish a GPS lock (not sure why in this instance). I didn't feel safe flying because the lag was persistent, so I landed the Spark and tried another flight with the OTG cable, figuring that perhaps I was getting Wifi interference from the neighbors. The flight with the OTG cable was much smoother and I was able to get the photos I wanted. I compared the records of the two flights and saw a lot of "Downlink restored" messages on the first flight but no errors, fortunately. However, I've been on this board long enough to know that those can precede more serious connection issues people have experienced.

I've been able to fly the Spark in my neighborhood with no OTG cable and have been fine. But it is nice to have another option available.

I was a heavy OTG user. I'm slowly retiring it.
I've been having much better video stability and quality without the OTG. The opposite from what you are experiencing. I guess it all depends on the environment your flyin in.
But as you said its nicer to have the 2 options.

I've never used an OTG cable and have always been very happy with my Spark's range and performance. Being in Canada I do get FCC mode though, which is probably why it works well without OTG.