The Application of Vacuum Tube Amplifiers to Submarine Telegraph Cables

Vacuum tube amplifiers have been developed for use in submarine telegraph reception and at present are in successful operation on four high speed permalloy cables. There is no limit to the speed at which vacuum tube amplifiers may be operated and in the present stage of development, the rate at which messages may be passed over loaded cables of the length used in the Atlantic Ocean is determined by the cable itself and the mechanical transmitting and receiving apparatus. I n regard to maintenance, vacuum tube amplifiers have a great advantage in that they do not require any delicate mechanical adjustments.