As we now, based on CE regulation DJI SPARK Max transmission distance in Europe is limited to:
2.4 GHz - 500m
5.8 GHz - 300m

Maybe we could post here the best flight distance we have reached so far, before starting to lose image transmition signal
In form:

Distance reached:
Country:
Open area: Y/N
USB-OTG Cable: Y/N
Frequency, GHz: 2.4/5.8
Airplane mode: Y/N
Signal Booster: Y/N

Distance reached:  173m
Country:  Denmark
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N
Signal Booster: N

Distance reached:  1049m
Country:  Denmark
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 2.4
Airplane mode: Y+N
Signal Booster: N

Distance reached:  497m
Country:  Denmark
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N+Y
Signal Booster: N

Distance reached: 536m
Country: Switzerland
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N
Signal Booster: N

Distance reached: 1636m
Country: Germany
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 2.4
Airplane mode: N
Signal Booster: N

Distance reached: 444
Country: Romania
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N
Signal Booster: N

Am I doing something wrong? My distance is lowest.

Distance reached:  112 m
Country:  Slovakia
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N
Signal Booster: N

Distance reached:1200 m
Country:Greece
Open area: Y
USB-OTG Cable: Y
Frequency GHZ: 2.4 ghz
Airplane mode:Y
Signal booster: N

Anuvis Posted at 2018-1-7 01:02
Distance reached:1200 m
Country:Greece
Open area: Y

You have OTG :Y - Is that an old flight or recent flight? Are you still on old Phone Software?

Yes with 2 versions back firmware and 4.1.14 app

Just for info I fly with and without OTG, trying to establish best system. I have included both flights in my feedback. (with OTG I have constant "Weak Image Transmission", but no problems during flight!, without OTG (Wi FI) there is no message for "Weak Image Transmission")

Distance reached: 675m
Country:  Austria
Open area: Y
USB-OTG Cable: Y
Frequency, GHz: 2.4
Airplane mode: N
Signal Booster: N

Distance reached:  821m
Country:  Austria
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: N
Signal Booster: N

Still on dji go 4   4.1.15
Distance reached: 422m
Country: Singapore
Open area: Y
USB-OTG Cable: Y
Frequency, GHz: 2.4
Airplane mode: Y
Signal Booster: N

Today 07/01/18
WiFi 2.4ghz
iPhone 7
710 metres
WiFi 5.8ghz
iPhone 7
314 metres
Up to date FW/SW
No loss of transmission both runs to last bar of signal could have flown further.

Distance reached: 203meter
Country: South Africa
Open area: Y
USB-OTG Cable: Y
Frequency, GHz: 5.8  (I think)
Airplane mode: N
Signal Booster: N

Had just performed compass calibration due to compass errors and signal loss.
Probably would have gone further but I could no longer see the spark against the background.

What I have learned is that if there is wifi interference then signal loss occurs.

Update!
Just did 300 meters!

Distance reached: 250m
Country: The Netherlands
Open area: Y
USB-OTG Cable: N
Frequency, GHz: 5.8
Airplane mode: Y
Signal Booster: N

I've set a while ago the max flight distance to 200m in DJI GO 4 app for the following reasons:
1) On average I get choppy/laggy response beyond 200m distance which is annoying.
2) On average I barely can see the Spark beyond 200m which feels very uncomfortable.
3) Maybe the most important; Dutch flight regulation rule: "keep your drone in sight throughout the flight".

Distance reached: 1435 mtr
Country: The Netherlands
Open area: Y
USB-OTG Cable: Y
Frequency, GHz: 2.4
Airplane mode: Y
Signal Booster: Y forced to FCC mode.

Based on DJIGO4 4.1.15  mod version
CE mode max range 375 mtr