A compact, multitube steam reformer converts a fuel into a reformate stream comprising hydrogen. A request to establish a CSFB call may be received by a UE that is currently in a pool overlap area. Because the rotor 5 and the vane 7 can be made as one piece with an NC machine, precluding the occurrence of gaps in the otherwise-inevitable joint between them, it is easy to make the rotor 5 and the vane 7.