. A study of wireless telegraphy and wireless telephony . lts, the primary circuit can be interrupted with anordinary Morse telegraph key provided with heavy platinum orsilver contacts. For larger values of the power, some form ofrelay key by which the current is broken between large contactsunder oil is generally employed. The adjacent diagram shows theconnections for a complete station, the sending apparatus beingshown at the right and the receiving apparatus at the left anda cut-over switch for throwing from sending to receiving is shownnear the center. This switch usually has three blades,
. A study of wireless telegraphy and wireless telephony . lts, the primary circuit can be interrupted with anordinary Morse telegraph key provided with heavy platinum orsilver contacts. For larger values of the power, some form ofrelay key by which the current is broken between large contactsunder oil is generally employed. The adjacent diagram shows theconnections for a complete station, the sending apparatus beingshown at the right and the receiving apparatus at the left anda cut-over switch for throwing from sending to receiving is shownnear the center. This switch usually has three blades, mountedon a hard rubber axle, and sufficiently far apart to avoid spark-ing between the blades of the switch or from the sending to the s4 61. Receiving Sending Helix receiving apparatus. The switch is shown in the position for Antenna sending; twoof the bladesjoin respect-ively the an-tenna and theground to thesending helix,and the third ^wvaAaa- Po feniiom. blade closesthe line circuitto the key andtransformer,ihen the switchis thrown tothe left, the. VariableInductancewirh Tron Core Fig, 37Diagram for Transmittingand Receiving 1nstat/crfions . antenna and ground are joined to the primary of the inductivelyconnected receiving transformer, and the line circuit is openedso as to avoid a possible accidental discharge of the high-pot-ential circuit while receiving. Receiving Apparatus: Some decided advantages are gainedby using an air condenser of the semicircular plate type forthe series condenser used in the antenna circuit between the pri-mary of the receiving transformer and the ground. The use of thisseries condenser, however, is not absolutely necessary in theprimary circuit, unlike the secondary circuit, where it not onlycannot be omitted, but must also have a larger capacity. The detectors commonly used at the present are of theelectrolytic or crystal-contact type. The sensitiveness oi the 62. detector and its readiness to detect signals may be tested by abuzzer device f
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttheses, bookyear1915
