Circular slide rule with instruction booklet and pouch, Radio Transmission Line Calculator, plastic / paper / leather, made by W & G (White and Gillespie), Melbourne, Victoria, Australia, c. 1940
Slide rule, Radio Transmission Line Calculator, two plastic disks with cursor. Engraved with logarithmically spread polar graphs. With instruction book. Leather pouch in poor condition.
On pouch: Radio Transmissioin Line Calculator - DCA Ident No G65/2 (?)
made by >W & G< Melb. Aust - for - Commonwealth of Australia - Department of Civil Aviation.