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Show DAMPED WAVES WILL BE ABANDONED j BY H. I. DUNCAJi Director, Radio Institute or mri a With the rapid strides In the advancement ad-vancement Of radio, the dlBCOntWU-j . ous or damped waves are going by the board. Transmitting stations at-j at-j using direct current for their 9uurce of power anrl their waves go oul In continuous fliw. THeas i "nt inuous nr undamped i waves are generated for the most part by vacuum tubes, although the trnns- lailantic stations "f the Radio Ci.rpo- I ration of America employ the Ab x-andersen x-andersen radio frequency alternator land the I'mi'd States navv uses a dl- ' rei'l current arc generator. But the largi broadcasting stations I use the vacuum tube. i n account of the different charac- iterlstlcs at the two types of waves, the ordinary crystal receiver cannot receive the code signals rent out by stations employing dir..t tirrent or continuous waves. The frequency of the current, even after being rectified by the detector and passing through the head phonos, 1 uiiiiiiyiiuuuuii i Is above audibility; No sound is heard except the opening and closing of thu circuit. CANT HI' AH CODIES. While one may hear radio telephony ; on a crystal director set, he cannot copy continuous wave code messages on it. The broadcasted sound Is sent out by radio frequency wave motion termed the carrier wave. Tills Is modulated at an audio frequency fre-quency by the phone into which the operator speaks. Code messages bent lout on a continuous wave do not en-Joy en-Joy the same advantage. ! For the amateur desiring to listen In on all code .signals as well a broad-casted broad-casted music and lectures, the regen-; regen-; eratlve receiving set should be -used. As tlm continuous or undamped waves come through the air. they are received on the regenerative circuit in for mot diagram 1. No. 2 represents the local waves generated by the vacuum tube In the 1 regenerative set. So. shows the difference of the two applied frequencies, represented by 1 and 2. Xo. 4 The rectified beat eurrojits No. ri The telephone current. |