The ornamental design for a portable waveamplifier, as shown and described.
FIG. 1 is a perspective view from the top and left thereof;
FIG. 2 is a back view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a perspective view from the front and right view thereof; and,
FIG. 9 is a side perspective view thereof showing the design as part of its environment and connected to and positioned at the back of the watercraft.
The broken lines are for the purpose of illustrating portions of the portable wake amplifier that form no part of the claimed design. The intermittent broken lines in FIG. 9 represent the environment in which the article resides. None of the broken lines form a part of the claim.