This is becoming muddy again....
Indeed!
This subject has been debated many times, and I'm not an engineer in this field..
Lets start with Spark specs:
Now, check CE dBm vs FCC dBm.
Spark's RC has an output of ca 400 mW in 2.4 band and ca 630 mW in 5.8 band..
When fabricating products which is WIFI operated, by law and regulations you are bound to certain bands (2.4/5.8) and channels (frequencies).
Equipment will never be certified for use or sale without lab tests etc..
Well, CE say 400 mW and/or (whichever limit is reached) 18 dBm in 2.4 band and 14 dBm in 5.8 band.. while FCC will do 26-28 dBm.. you get the point.
To complicate the muddy puddle some more..
The frequencies/channels in the 5.8 band is basically forbidden in CE region, and these regulations is set by sales region and sim card.
DJI obviously made a compromise and lowered 5.8 band output to indoor levels.
This is why CE pilots must avoid any 5.8 band connections at all cost. Their device to RC connection will grab 2.4 band over Wifi, which leaves 5.8 band to RC/AC connection. We're talking Auto configuration regarding this..
When Android users switch to OTG, its another story.
2.4 band/channels is now free for use by the RC/AC connection.
In combination with FCC "hack" this will be your best and most stable connection.
Unless you are in an overpopulated 2.4 Ghz (home networks) area..
Apple devices?
Apple doesn't give a ****.
Same output in all regions..in both bands.
They do not allow sim card access to the wifi "radio"..
That's why Apple devices will be recommended by everyone.
It just work..
I wonder how many pallets of devices Apple shipped to the governments 10 years ago.