Also, if you have beans (bush or pole), fruit trees, birch trees, or roses, the japanese beetles would already be seen on any of these. They will prefer those crops to hops without question.
I ordered my wire rope from:
http://www.safelandindustrial.com/app/stx.products.asp?cid=4
I picked up thimbles, eye bolts, wire rope (1/4" will be plenty since you are not using a stringer from the top of 2 poles), turnbuckles (you'll want one on each line to adjust tension), and don't forget the sleeves (and something to crimp them)...