Yes, and it must be registered on 406registration.com.
BIPT advises you to buy an EPIRB that is MEOSAR compatible.
Yes, this system is subject to an authorisation issued by BIPT and must therefore be added to your application for a station authorisation.
A station authorisation is required for a radio (TX/RX), a DMA, an ELT (fixed or portable), a radar, a transponder, an ATC transponder, a TCAS, a VDR, a weather radio, a radio altimeter, a satellite communication system (SATCOM)... This list is not exhaustive but an authorisation is required for all devices emitting electromagnetic waves. In case of doubt, please contact our department.
Yes, however, you must apply for a special authorisation. You will find more information on the page Professional users – Mobile networks
The use of radios from the ground as an instructor or in AFIS (Aerodrome Flight Information Service) is possible but is subject to an authorisation of another category.
Both. An aeronautical authorisation is required when airborne but a maritime authorisation is required when on water. Furthermore, it can use a PLB: a device which can be activated by the user in case of emergency. That type of device is not subject to an authorisation in Belgium, provided that it is registered by the user via www.406registration.com.