Show va 5 HOW AN INDOOR LOOP ANTENNA IS BUILT i has advantages in size sh and directional ional properties aut b ut picks up little energy if you live in et section of kif the country infested with radio fans who spud send or send some station call by the hour bour while you are to catch the lie must from froin a broadcasting station a loop anten arten help solve your dIllI difficulty culty or if you live in an apartment or a very congested section of tho the city where there Is no room to erect in an antenna or where tho the landlord objects a loop antenna antana can be used lit in lieu of on nn outdoor one let it be thoroughly understood however 4 0 x ILI z 41 jr 71 at that the energy picked up tip by a loop antenna only lipp approaches roaches that ot of tin nn outdoor antenna when ti the ie physical dimensions of the loop antenna approach those of the outdoor antenna dont wind a hundred feet ot of wire on a ll mothers others oats hoi box and eap exp expect ct a loop antenna so go constructed to give the same signal strength as tile the same hundred feet of oc wire lre stretched outside as a wire outdoor antenna the two advantages of it a loop antenna then tire are its small physical dimensions men and its directional properties the most serious disadvantage of the loop antenna Is the small amount of nt energy picked up tip if loop antenna Is used for flip reception of close high stat stations Inns ordinary regenerative receivers receiver with audio fre quency amplifiers vill give go good od results however it if a long ions distance reception of medium and ami low power transmitting stations Is desired then lien radio frequency must be used there has hern been placed on the market it frequency amplifying transformer type UC 1714 to he be used in conjunction with troi is type UC such a Is claimed to give oil an audibility amplification of 20 per stage A loop imp autentia antenna with a two or three stage fadlo frequency amplifier employing type UC 7 coupling transformers in canji I 1 notion with ones ones pre present ent set will give practically the signal strength that Is now being r received front from the outdoor antenna though a loop finten antenna nn of larger section end and fewer turns would be more tile antenna described here will phe give good result for its size she and Is iq gin small ill enough to li he easily transported the required ired for the two loop antenna Is as aa rol follows lows two strips of wood R feet long hy by 2 indies wide ide hy by 1 inch mick Str alghi close grained wood bowl should lie he used in order to guard warping one feet of no 14 bore baie antenna wire preferably Fartin stranded ded chor bronze pour four pieces places 2 indies square by MC 3 16 inch four small brass arns angles of tile type that can he be in the 5 1 tin and 10 cent stores one dozen IIA IA inch long 13 1332 32 brn brnt aras t inac lilii with nute notch the to 00 pieces of wood it in tile the center rind nt at the ends ns nit bhain fn an fig figure ire ill III then with adith rk n no 25 drill drift bore three holes in each piece of wood ns as shown tile the notches clies in the lie center part of tile the two of wood should allow tile the two clems alc plc es to t ie be fitted together to form n p erfft angle the notches should lie just so that tha oni of the four 2 inell inch square pieces of elite will JW just st fit after tile notches have aae been checked to see that they art an of tiie the proper size fit the lie two strips of together putting a n little glue in the joint and belting it fast with a 0 long hot bolt I 1 the oagle aigles 14 should now he be fitted in the corbra of tile tho plat to imil malic e um uin two strips of wood form ft 01 right to pre warping and for the sake of app i rance the woodwork should ilion ld be alven several of shellac the natural pirlon of tilts this loop anterina antenna is 17 1 meters rr to 0 june to wave vae depths 11 ii f leess of meters it 11 condenser la Is shaunte I ucros across ucro s tho the leads of the loop ilia 1110 closed oscillating circuit formed ly by the hap hinl anti the lie condenser can lie be connected by any detecting circuit us miltonn in fag I 1 or can be used with biallo frequency amplifiers who when 1 hipfl I iiii receiving sets gets employing a vuro couple and two the loor loop Is connected and the shunt condenser Is IH omitted the tuning la Is accomplished by means of the grid vart ometer A loop antenna will pick up n maximum amount of energy when the transmitting station Is in the plane of tile loop and a minimum of energy when tile transmitting station Is in a direction tit nt right tingles angles to tho the plane of the loop in fig 11 the loop will ft pick up tip a maili maximum nuta of energy front from A and a minimum amount from station 13 care caie must bo be taken lit in setting up a loop to see BOB that it hlll all not lie be the energy picked up by it 11 loop antenna Is small tit nt best especially it if the loop Is not oriented to its maximum position and any ye reduction in received energy will decrease the lie signals below audibility for example dont set up n loop antenna inside a steel framed building or up in th the I 1 attic under a well grounded metal roof capacity effect due to the body of the operator Is quite noticeable with a loop antenna anten nn the operator must not get close to the loop or the capacity effect of ills body will detune the oscillating circuit while the loop Is rather dini cult to handle in some soine instances and can only be used to replace sit an outdoor antenna at a loss in received energy KB its directional properties are very advantageous in the reduction of interference |