The ornamental design for tether coupler for placement on a rope without passing a rope end therethrough, as shown and described.
FIG. 1 is an isometric view of the tether coupler for placement on a rope without passing a rope end therethrough showing my design, with a rope shown in broken lines for illustrative purposes only and forming no part of the claimed design;
FIG. 2 is an elevational view of the back or front thereof, both of which views are the same;
FIG. 3 is a bottom view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a right or left side elevational view thereof, both of which views are the same.