http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F009%5F002%5F000&product%5Fid=278%2D238
one of these works really well, you just gotta use the one ment for RG6 coax, then use the flatter inner side ment for measuring the conducter on top of it. need...