The ornamental design for a radioreceiver for a hearing aid, as shown and described.
FIG. 1 is a rear view of a radio receiver for a hearing aid, showing our new design;
FIG. 2 is a left side view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a perspective view thereof.
Portions of the drawings shown in broken line represent unclaimed portions of the radio receiver for a hearing aid, and form no part of the claimed design.