. The Bell System technical journal . ca unS CQ > co. 1-4 > CJ(U o 13 I +-> O in bO S TRANSOCEANIC TELEPHONE SERVICE 285 stage require tuning when the frequency is changed. Hence to tunethe receiver on any one of the assigned frequencies the attendantmerely moves the dials of the second stage to predetermined settings,switches the grid circuit to a first stage which is already tuned andconnected with the proper antenna and he adjusts the beating oscillatorto obtain an intermediate frequency of 400 kilocycles. Screened gridtubes are used for the first two stages of amplification. A key
. The Bell System technical journal . ca unS CQ > co. 1-4 > CJ(U o 13 I +-> O in bO S TRANSOCEANIC TELEPHONE SERVICE 285 stage require tuning when the frequency is changed. Hence to tunethe receiver on any one of the assigned frequencies the attendantmerely moves the dials of the second stage to predetermined settings,switches the grid circuit to a first stage which is already tuned andconnected with the proper antenna and he adjusts the beating oscillatorto obtain an intermediate frequency of 400 kilocycles. Screened gridtubes are used for the first two stages of amplification. A key shelf isprovided with telephone and telegraph facilities. The power plantconsists of standard 24-volt and 130 batteries, rectifier charging unitsand automatic regulators. Receiving Antennas In discussing antennas for directional sending it was mentionedthat an identical antenna could be used for receiving purposes, butsince the requirements in the two cases are not the same, quite dif-ferent structures have been developed, although the metho
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
