The ornamental design for a pedestalbase, as shown and described.
FIG. 1 is a perspective view of a pedestal base in accordance with the new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines in the figures are for environmental purposes only, and form no part of the claimed design. The pedestal base is shown with a symbolic break in its length in FIGS. 1-5. The appearance of any portion of the article between the break lines forms no part of the claimed design.