An investigation of symmetrical screened transformers for h.f. radio direction-finders

The purpose of a symmetrical screened transformer for application to h.f. direction-finding is pointed out, and the requirements are stated. Equivalent circuit theory for symmetrical screened transformers is given, and the symmetry factor defined. Methods of balancing are described. Experimental evidence in support of the theory is provided, and the principles of mechanical design are discussed. Results of measurements of the symmetry factor on two typical transformers are given, and the values of the equivalent circuit constants are determined.