Re: internal vs external
> Is this internal or external signal reception
You won't know. All these organisations are reporting are the outputs of their apps, that are installed on a subset of subscribers of each network. The apps just sit in the background and sip the RF measurements from the phone, and perhaps also occasionally perform throughput tests if they are configured that way (i.e. the user doesn't care about their mobile data usage!). The phone doesn't have any inkling as to whether it is indoors or outdoors, although I'm sure you could possibly frig a reasonably accurate metric together based on GPS measurements (i.e. if the mobile is stationary and not on a road, or if there are no measurements available, then it's probably indoors).