I set up two pulleys a hundred feet apart to swim hounds used quarter inch wire rope and bring it in and out manually.My problem is the cable rolls over and back as I let it out or bring it in. I don't know what causes this and was wondering if anyone did and how they fixed it so cable would flow straight.

try reverse cable to opposite end

This is probably a stupid question. Why would you swim hounds for, is this a new competition like the Lab hunt test or something?

Take the front wheels off two bicycle tires. Remove the tire and the cable will rest between the lip of the rim. Use the y frame and drill a hole accordingly through the 4x4 post bolt the frame through the post works flawlessly and you can put pretty good tenchon on the cable.