Can't tell you where to go, but I cna tell you what to look for. I found some clear green plastic coated clothesline wire at the hardware store (Orchard Supply in California) by my place. The inner wire was braided and very strong. Much stronger than what is used in the white plastic coated stuff. Came in 50 and 100 ft rolls and was about 8 bucks for the bigger roll. Look for it as it is really tough. I use it for end lines on copper wire antennas. Doesn't seem to stretch with use.