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Show HOW TO TEST SUPER-REGENERATIVE RECEIVER ; By PAtJL F OODLFY, Amcrie a' . I"r iin . F.neJIo Authority.' Thtfl is the last of a series of articles on the Arm-lrong sitpe-r- r'egcneratlve receiver. If there is any difficulty ln putting the supSr-regeneratlve rooeivcr into operation, teal each of tin- vacuu: i tuben separately. With ono of these working, place the telephone receivers ln tho plate circuit of the tube until you are satisfied sat-isfied that it Is operating properly. t'sing the telephone ln the circuit of any of the tubes will not affect the operation of tho circuit, if tho phones are at all times srunted by a by-puss condenser For example, plat lug the telephones In the plate circuit of the oscillating tube will enable one to ase ertaln whether the radio frequency oscillations oscilla-tions are present. If they aro not. something Is wrong. Either the tubej Is not oscillating or, If It Is, the fre-iiuency fre-iiuency of oscillations Is too high to be- heard and full amplification cannot be derived from the circuits as x whole, OSCILIiATIONS. In determining whether a circuit Is oscillating, It is only necessary to touch Its grid terminal. If a "pluck'' In heard In the telephoneja, both when Ihe finger touches eind when ii Is r-.-movod from the grid terminal, tlo-r are oscillations The degree- of coupling between the grid and the wing t plate) clr- i nits of the regenerative tube will! have to be much greater for super-1 regeneriil i ve operation than for oscll-' la tory indication when the tube Is op-' erating alone With pome makes Ot tubes tills coupling win have to be somewhat closeT than thut provided with tho coll and variometer arrange--ment shown previously To accomplish this, tho variometer may either be rewound so that It carries car-ries 50 per cent more turns, or t It tube which supports the grid circuit winding may be sufficiently large o slip over the variometer half way. ARRANGEMENT. The larger colls of the grid and plate circuit of the. oscillator tube should -not bo placed near each other. If this Is done it may offer a capacity ca-pacity path for the currents which the choke coll controls, or it may effectively ef-fectively prevent oscillations in tho oscillator tube circuits. In arranging them on the tablo or panel, they should either bo kept well apart or so set as to be at right angles to each other. |