This paper describes a simplified waveguide CO2 laser which can be used in length and distance measurement as a local oscillator when used in conjunction with a heterodyne technique. The dependence of the tunability and output power on the pressure and discharge current were investigated and compared with the phenomenological theory of Degnan. [J. J. Degnan: J. Appl. Phys. 45 (1975) 257]. The use of this laser, which has tube and cavity lengths of 280 mm and 620 mm, respectively, gives an output power and tunability of up to 0.8 W and over 300 MHz, respectively, on the 10P(20) transition line, with good wavelength selectivity in the 10 μm band and also with good discrmination of the EH11 mode from other transverse modes.