A Nationwide Frequency-Modulation Telegraph Network

With one exception, the carrier telegraph systems of the major record communication companies of the world are operated by the old familiar amplitude-modulated (AM) method. That exception is the huge trunk line and tributary network of the Western Union Telegraph Company which, while realizing excellent spectrum economy, employs frequency modulation. It is the object of this paper to report on the success achieved in operating that network. Years of experience with thousands of frequency-modulated (FM) telegraph channels have demonstrated they may be operated in long tandem chains with excellent continuity of service.