This balun documented by I0QM use a ¼ wavelength and the ¾ wavelength adapting sections with the 50-Ohm coaxial cable, or a coax line with the impedance you need.
A 1:1 Coaxial Balun
This balun documented by I0QM use a ¼ wavelength and the ¾ wavelength adapting sections with the 50-Ohm coaxial cable, or a coax line with the impedance you need.