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Radio Record, Volume I, Issue 40, 20 April 1928, Page 12

necessary. "When the receiver is completed and connected up it may be neutralised by setting the dial at about 20 on the scale and turning the tickler in either direction until a distinct click is heard in the loudspeaker or telephones, Adjust the tickler coil until this circuit is not oscillating. A test to Jetermine whether or not the set is oscillating is to place the finger on the terminal of the $ mfd. blocking condenser, which, if connected to the grid of the second tuning circuit (to get at this condenser the top of the shield on the r.f. compartment will have to be removed), a distinct click will be heara if this circuit is oscillating, Now turn the tickler back to where oscillating just ceases. Turning the trimmer condenser will then throw this circuit into oscillation if the neutralising condenser is not properly set. ‘The neutralising condenser should he then set until the above test is satisfactory and the trim mer condenser has no effect on oscilla. tions produced in the second circuit, It will be found that this trimmer condenser is almost at a minimum value. "Too much cannot be said in favour of using the screened grid valve as a radio frequency amplifier. The ampli. fication obtainable is tremendous, and the operator can easily get down to the ‘pise level with little or no difficulty." |