For example, transformation of 300-Ω twin-lead or 450-Ω ladder line (balanced) to 75-Ω coaxial cable (unbalanced), or to directly connect a balanced antenna to unbalanced coaxial cable. To avoid feed line radiation, baluns are typically used as a form of common mode choke attached at the antenna feed point to prevent the coaxial cable from acting as an antenna and radiating power. This typically is needed when a balanced antenna (for instance, a dipole) is fed with coax; without a balun, the shield of the coax could couple with one side of the dipole, inducing common mode current, and becoming part of the antenna and unintentionally radiating.