Get a 20' length of decent size rope, either 3/8" or 1/2".
Cut off 2 @ 2' lengths.
Get 16" length of 1" pvc pipe; cut it in half. These are your 2 handles.
Thread each 2' length through each 1" pvc handle.
Tie each handle into a loop (a sheetbend or zeppelin bend knot works well). Attach to remaining 16' rope using a prussik knot.
I've made a couple this way and used one or the other for dozens of workouts. My Irish cousins call it Ropey.