. Radio for everybody; being a popular guide to practical radio-phone reception and transmission and to the dot-and-dash reception and transmission of the radio telegraph, for the layman who wants to apply radio for his pleasure and profit without going into the special theories and the intricacies of the art . ergy which is about to be passedon to the telephones is partly re-impressed on the gridof the vacuum tube, it will add materially to the voltageof the incoming signal. This will naturally give a greatercharge on the grid, and consequently a greater variation RADIO FOR EVERYBODY 139 of p
. Radio for everybody; being a popular guide to practical radio-phone reception and transmission and to the dot-and-dash reception and transmission of the radio telegraph, for the layman who wants to apply radio for his pleasure and profit without going into the special theories and the intricacies of the art . ergy which is about to be passedon to the telephones is partly re-impressed on the gridof the vacuum tube, it will add materially to the voltageof the incoming signal. This will naturally give a greatercharge on the grid, and consequently a greater variation RADIO FOR EVERYBODY 139 of plate current, which in turn means louder signals. Inthis manner the sensitiveness of the vacuum tube is greatlyincreased; indeed, it is operating as a detector and anamplifier combined. This practice is known as the regen-erative or feed-back reception. But how is the plate energy re-impressed on the detec-tor? There are two methods in general use for obtainingthe regenerative effect. The first makes use of what isknown as the tickler—an extra coil which is brought nearthe inductance or winding of the detector or oscillatingcircuit. Thus the simplest type of regenerative receiverconsists not of two compact inductance coils but of threecoils, adjustably mounted, as shown in the diagram on f A ri VCt \-. R. FC-<o)Jo)-l Another method of obtaining regrenerative results. A—antenna; P—primary; S—secondary, of the vario-coupler C;VCl—variable condenser in antenna-ground circuit; VI—variometer; GL.—grid leak; VC2—variable condenser as gridcondenser; VT—vacuum tube detector; V2—plate variometerfor feed back; FC—fixed condenser; T—telephones; B—high voltage or plate battery; R—filament rheostat; Kl—high voltage battery rheostat. page 138. The first coil is the primary, connected withthe aerial-ground circuit as already mentioned, and thesecond is the secondary, connected with the detector. Thethird is the tickler, and is connected in the plate circuit,as
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