DALLIN DISCUSSES RADIO FREQUENCY AMPLIFIERS

"The whole object of radio frequency amplification is to amplify the energy before it gets to the detector," declared Mr. E. B. Dallin in a lecture last night to the Wireless Club at the Cruft High Tension Laboratory. He pointed out that this was essential in securing the maximum of sound without sacrificing clearness. He then diagrammed the various methods of setting up a set by which one can increase the intensity of sound without being troubled by excessive sputtering from the instruments. Mr. Dallin discovered in particular the relative disadvantages of the regenerative, crystal, and reflex receiving outfits, favoring the crystal detector as the best receiver of music. In speaking of the possible strength to which such sets can be developed, he mentioned the fact that Great Britain built a 19-stage regenerative amplifier in the late war which enabled her to hear the German Navy practicing its signal codes in the Kiel canal, while an ordinary instrument could not hav epicked up a message a half mile away. His points, were demonstrated by a set placed in the room by which he got in touch with stations in cities as far away as New York and Schenectady, in spite of the disturbing influence of the storm. To the great surprise of those present, he was able to get remarkable results by putting his fingers on the tapes to which the antenna wires were originally attached, thereby proving that the human body may serve as an antenna under certain conditions.