The pilot was spraying a potato crop in a paddock which had a power line running along one boundary. Spray runs were conducted at right angles to the wires, and the pilot was flying under the wires on each run. At the end of one run the pilot pulled up, conducted a procedure turn, and was then slightly distracted by noise on his CB radio. While adjusting the squelch on the set, he forgot the presence of the power line and the aircraft struck the wires about 32 feet agl. The aircraft remained under control and the pilot was subsequently able to make a normal landing at his destination strip.