. The Bell System technical journal . mobilecommunication itself. This paper describes general characteristics and quantitative meas-urements of the received signal on megacycles. Transmission * Published in Electrical Engineering, January, 1935. 1 J. C. Schelleng, C. R. Burrows and E. B. Ferrell, Ultra-Short-Wave Propaga-tion, Proc. I. R. E., Vol. 21, pp. 427-463, March, 1933 and Bell Sys. Tech. Jour., , pp. 125-161, April, 1933. 253 254 BELL SYSTEM TECHNICAL JOURNAL phenomena were studied in both directions between a fixed locationon a- building and the mobile laboratory. Apparatu
. The Bell System technical journal . mobilecommunication itself. This paper describes general characteristics and quantitative meas-urements of the received signal on megacycles. Transmission * Published in Electrical Engineering, January, 1935. 1 J. C. Schelleng, C. R. Burrows and E. B. Ferrell, Ultra-Short-Wave Propaga-tion, Proc. I. R. E., Vol. 21, pp. 427-463, March, 1933 and Bell Sys. Tech. Jour., , pp. 125-161, April, 1933. 253 254 BELL SYSTEM TECHNICAL JOURNAL phenomena were studied in both directions between a fixed locationon a- building and the mobile laboratory. Apparatus Both terminals employed vertical half-wave antennas which wereconnected to balanced circuits by means of symmetrical two-wiretransmission lines. At the fixed locations unloaded antennas wereused; at the mobile terminal, in order to limit their heights to eightfeet above the ground and maintain the symmetry the antennas wereloaded so that their lengths were reduced to about a quarter of awave-length (Fig. 1). \±i&-imi^mumM^^.. Fig. 1—Mobile receiving equipment. The transmitter consisted of an electric oscillator employing two75-watt tubes operating in push-pull relationship. At the fixedlocation, where ample power was available, the transmitter was capableof producing one ampere ^ of 100 per cent modulated carrier in itsantenna without undue distortion. The mobile transmitter whichused a dynamotor for tube plate supply was capable of producing thesame current in its antenna. This corresponds to about six decibelsless power due to the shorter antenna length. The measuring set was of the double detection type with balanced high-frequency circuits, push-pull first detector and calibrated inter- 2 The current was measured b> a Weston t)pc 425 thernioammeter at the currentniaxinmm. ULTRA-SHORT-WAVE PROPAGATION 255 mediate frequency attenuator.* This receiving equipment was cali-brated in absolute units by a method described in the mechanism for recording the field
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