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Show MEANING OF "FREQUENCIES" Distinction Between "Audio" and "Radio" "Ra-dio" Must Be Learned Early by the Beginner. A newcomer Into radio experimenting experiment-ing ranks Is often perplexed by the two terms called audio frequency and radio frequency. The necessity of making a distinction distinc-tion in the frequencies in radio Is Important. Im-portant. It is generally known that vibrations of over 20,000 a second are Inaudible to the human ear. The radio transmitters, depending upon their design, de-sign, emit vibrations always running into tens or even hundreds of thousands, thou-sands, and are known as radio frequencies. fre-quencies. In the reception of these waves It is necessary to reduce them to within the range of audibility of our ears. Therefore, an arbitrary division has been made by radio engineers and designers de-signers to differentiate between the two frequencies. All frequencies above 10,000 are alluded to as radio frequencies fre-quencies and all below 10,000 as audio frequencies. It must be remembered whenever the question of frequency Is met with In the study of radio that radio frequency fre-quency is that used in transmission, and that it must ultimately, by various methods, be reduced to audio frequency fre-quency in order that the telephone receivers re-ceivers commonly used for the reception recep-tion of signals may function. This is analogous to the transmission transmis-sion of power over great distances by wire, it is generally carried at a high voltage over the greater distance, and. by means of step-down transformers, converted to a voltage of 110 volts, ordinarily or-dinarily used in our household scheme. By means of detectors, either crystal or tube, which are really rectifiers, we convert radio frequencies to audio frequencies. fre-quencies. These detectors lop off, as it were, one-half of the cycle, permitting permit-ting only a flow in one direction, the other alternation being almost eliminated. |