ATU for 27-MMHz CB radios

This antenna tuning unit (ATU) enables half-wavelength (1⁄2 λ) or longer wire antennas to be matched to the 50-Ω antenna input of 27-MHz Citizens’ Band (CB) rigs. The ATU is useful in those cases where a wire antenna is less obtrusive than a roof-mounted ‘vertical’ or ground-plane.