Some Results of a Study of Ultra-Short-Wave Transmission Phenomena

coincidently with that described in the companion paper by Schelleng, Burrows, and Ferrell. It deals in particular with the establishment of the presence of various ground reflections which must be taken into account in computing ultra-short-wave transmission and with the local disturbances due to both stationary and moving near-by objects. APPARATUS 2 The transmitting apparatus used by us possessed little novelty; one type of generator has already been described in an earlier paper, a second type consisted of a pair of 75-watt tubes operated " push-pull" and fed by a constant-current modulating system of orthodox type. This latter apparatus served permanently as station W2XM at our Holmdel laboratory, and was ordinarily modulated with the output from a broadcast receiver. We first employed superregenerative re* Published in Proc. I. R. E., March, 1933. 'Schelleng, Burrows, and Ferrell, "Ultra-short-wave propagation," this issue of Bell Sys. Tech. Jour. Bell Sys. Tech. Jour., vol. 7, p. 404; July (1928). · 197 2