mikk: Onto the next Q, ADSB- you can see the flight id right?
Although flight ID is a part of the ADS-B message, at this moment the ADS-B info is generally not available in the cockpit. For flight ID of other traffic to be displayed the own aircraft needs to be ADS-B IN equipped, which at this moment is rare.
Can you see the flight ID if you are out of range of the ADSB ground transmitter, eg acft to acft? or is it acft to ground to acft?
The data can be received either from a ground transmitter (TIS-B) or directly from other aircraft (ADS-B). The advantage of TIS-B is that the ground station can combine ADS-B data with data received from other sensors like radar, but to use TIS-B you need to be in range of the ground station.
Direct ADS-B IN has the advantage that it does not rely upon a ground station, so it works anywhere. The disadvantage is that it only sees ADS-B out equipped aircraft.
The use of ADS-B for ATC and cockpit display of traffic information depends on the availability of an accurate ADS-B signal. At this moment in Europe 20%-30% of the traffic does not have ADS-B out capabilities. Those that do are not certified, so it is unknown whether the sent info is correct. Therefore at this moment it is impossible to rely on ADS-B for ATC or cockpit display of traffic information. From 2015 onward ADS-B (out) is expected to become mandatory for flights in European airspace. By then, all aircraft will need to be certified for operation in an ADS-B environment, and only then you can rely on the information it provides.