Ralph R. Batcher, Electronic Research Engineer is the inventor of the SLF (Straight Line Frequency) Condensor. He is also the author of:
- Radio Tubes, International Textbook Co., 1942 with Albert Hodges
- The Electronic Engineering Handbook, Electronic Development Assc., 1944 with William Moulic
- The Electronic Control Handbook, Caldwell – Clementys, 1946 with William Moulic
Mr. Batcher resided at 240-02, 42nd Avenue (Poplar Street) during the 1940s through the 1960s.