Show by 0 Var drop editor f cadlo 1 17 1 C D A 0 four tube circuit by THOMAS W DENSON the principle of neutralized tuned radio frequency fic quency Is attil iced in lie circuit given len lit in the ut of cached illustration to form fonn it receiver that Is lion selective ins I as good KW range and volume aluinc and la Is easy to lo built build anti operate the HIP most aing part ot of tit alu circuit Is the of constructing the ond the lite orce of the cur reat gioi io to prevent in the lie clr 11 ll viii ben benitel lie ano efto em art biown 1 l on in lie 11 q ill Agrall shunted by 1 H i dillrd oin for or tuning timing T here lie rind tire nic termed Irrin cd annd lire frizill 7 turn honeycomb volio toll in III till lif rollow n manner take a 75 turn coil cill ovil ni d on off 2 cirps lian then count intel buck 11 i turna on 1111 the file coll coil and carefully i nike ilc flit ln wire icv and take it tup top tills this tup top Is IL now count back 15 more alil another tap 11 ll it Is not iipp iier i sury to ili unwind the coils to take tl 11 sr so taps tile colls coils are then cinal ped br bp tween two IHO pieces of ai inel inclima ies square in which lime have been drilled holes to mount terminal posts J li t 0 rr 00 I 1 deral L I 1 J the ut ui tilt aliu loll coll aguet bani to pusi A tile second tup till made to post lost IS 13 anil the first tup tap to post 0 ord nid the outside end nil of the coll coil to top 1 U ille list first cull coll does docs not need lot 11 II taken out rod alg tills coll coil tills lias but bu three terminals A k C and D for convenience tn in moun it u tle imle Is drilled in lite hie corner of tile hak bakelite elite end pieces and n small bross tingle batted to tile the coll coil so tile lie oils calls van ain lie be mounted on oil one of the ut file condensers in mount j alio ile cil bolh ili they should bo be mounted at right angles to reduce any coupling ing betwee to them IQ q zero 1 i the connection to the lite rest of the apparatus Is made its shown lit in the Il the neutralizing con condenser denver 19 a small midget Mir lable condenser moun leil on the pone lii Uiel the rest of 0 the circuit presents nothing leolly new As to the lite theory of its operation the 15 urns of the lie first coll coil between heti veen 0 and D form till nn i primary pili nury circuit and ay by iy ronson reason of the inverse connection grounds tho the filament reducing body capacity tile condenser tunes the lie remainder of the first shiell Is tile the grid ald lit 1 pill to the tie tulie tillie the plute plate circuit of tile lie radio fre quenby tule tube includes 15 in ili tile second coll ai ond faring nn an plate orvi cull carly clr ly coupled to tile the tuned input ch cull of nf the detector it will mill be noted fi wever that tile portion of the coll call between C an mid D Is neither in the lie plate or grid circuit clr cir cult cut but Is disola liim ly coupled to both tho the end of Is connected through lag ing condenser to the grid gild or of the radio frequency fri quency tube now kow should there be any tendency of the plater plated circuit to feed back to 0 o the grid through the tube capacity it Is neutralize by nn an equal lind opposite feed buck back obtained from the lie extra winding on the coll coil per ier feet stability can call be obtained by tile the adjustment of the stabilizing condenser wit hut this flits condenser Is mounted roo on the vallel for a very ery good glod renson reason we could mount it fixed behind the panel but by tanking it adjustable gain in volume alume and selectivity Is obtained it Is well known knon that the greater the tendency of a radio frequency amplifier to osel lInte the greater tile the nm am but the instant oscillations tart start the amplification stops therefore when it signal Is IlIc kedi up lip a slight adjustment of the stabilizing condenser con denter Is made to slightly unbalance tile he circuit when the signals will be greatly strengthen circuit van mn ile be put right on oil else so to tn speak it would not lie ile practical to the circuits in till elih critical condition valle tuning fur for the set would KII into oscillation without warning hilt but 4 when it a trulon Is picked up it it Is to lo push the circuit up tip to the lie edgo edge of osel linting lut hot not beyond the receiver Is remarkably easy to hondli ami gives results equal to tiny any foi itle set et allt it possesses lilt all ohp nobility tobi lity of tle me neutro ditle ns as well sia ai tile selectivity anti and in addition the lie slight unbalancing a 0 ali alio op erdyne and te ledine circuits clial lia accounts acco unta for their efficiency new york world |