I have an app that does background scanning and a BLE device which advertises with a 20ms interval.
I have two iPhone 5S bought together and both with iOS 9.1.
I do have the same app on both phones and I'm using the same BLE device for my testing.
No other BLE apps are running.
When I'm advertising (app in backgroud, display off), iPhone 1 is seeing 5-10 packets per second and the iPhone 2 is seeing approx. 0.5 packet per second.
What may cause such a very big difference in dections - we are talking about a factor 10?
Kind regards
Freddy