While the instruction manual for my 2007 X5 indicates that a cellphone should be connected to the vehicle antenna to minimize potential interference (and improve reception), this does not seem possible without installing an eject box and phone snap-in adaptor. Yet I notice that the icon on the bottom of my Nav screen indicating a phone/bluetooth connection has what looks like a signal strength indicator. This signal indicator seems to change in strength as I drive suggesting reception is varying. I would think this could suggest that in fact the bluetooth connection is enabling receptivity via the internal vehicle antenna and is showing it. Alternatively it could merely be a replication of the signal strength readings from my cellphone which operates via the bluetooth connection and not via a snap-in adaptor.
Anybody know what is really being reflected by this icon?

__________________
BMWs: 2007 X5 3.0
2002 330xi
1991 525i (ret'd)
1985 325e (ret'd)