Note on the Effective Heating of Code Transmitters

By considering the frequency of letters and words in the English language it is found that in slow speed transmission of code using the theoretical spacing, the transmitter is in operation only 46.5 per cent of the time. A transmitter can accordingly be given a power rating for code that is 2.15 times the rating of the same equipment when operating continuously, on the basis of the same operating temperature. At high speeds of transmission the heating is slightly less than at slow speeds. The desirability of designing large transmitters to take advantage of the full code rating possible during periods of weak signals or heavy static is brought out.