No person shall have or operate upon any highway any vehicle not in the service of a county sheriff or other public authority engaged in police service or in the apprehension of criminals, which is equipped with or in or upon which there is carried any radio receiving set capable while affixed to or carried on the vehicle of receiving radio messages upon a wavelength less than 200 meters, except by permit of the safety-service director and subject to such conditions as he shall in any case stipulate.
('73 Code, § 71.21) Penalty, see § 70.99