Strange, should be really more. Got 600m at 5.8G and 1000m at 2.4G when fare from other wifi, in CE mode. But I got much less in urban area.
Any source of Bluetooth or Wi-Fi in some of your devices you take with you?
At longer range the spark is very sensitive to any obstruction between the RC antenna and the drone. Even your own body will cut signal... i mostly fly it from the boat and sometimes when swinging on anchor if line of sight gets disrupted the video signal flickers but gets restored right away if I move to get clear
With clear LOS, airplane mode on, otg, and the antennas correctly oriented I ve had no problem up to almost 4000' / 1200m. And that's usually standing within 20' or 30' of a high power router, cellular modem, and a bunch of phones and iPads scattered around making believe the link is actually pretty resistant to interference
I had that happen today but it was really quick. Lost connection then it came back within 5 seconds. Was up around 300 feet. Soon as it happened was like you are coming down. I think it was just the WiFi cutting out because I still had control. But it wouldn't let me get out of tripod mode even after I got it down to 7 feet. Ended up having to switch it to sport mode and back to get it to normal mode.
Try rebinding the remote controller to the spark, but keep the spark away a few meters distance from the remote controller when you do.
I'm just curious to see if this makes any difference for anyone else as it did for me. For some strange reason when I bound the remote controller sitting right next to the Spark, I got really crappy range out of it.