Some problems encountered in the design of marine transmitters

The paper gives a brief survey of the development of the marine transmitter since 1919, and points out that, although the basic signalling requirement has remained practically unchanged, many refinements have become necessary to ensure that the original purpose of the apparatus shall be realized as the radio frequency spectrum becomes more and more congested. Modern requirements regarding frequency stability, bandwidth, power output and keying are reviewed and some of the problems presented to the designer are discussed. Mention is also made of the G.P.O. type-approval tests.