Show bolted by 0 dous as ii bd ed tor of 0 cadlo me chand m g frame Vs nyle open per C rev t 5 tule C rc acu u it 5 nylo wad C acu double C r acu t ro if ciment type jr rEL EPHONE JA cha double C rev 0 wiring diagram of principal s of jacks because telephone jacks are widely used tn in many kinds of radio sets the radio fan would do well to familiarize himself with the various types there are five different styles and as many as three of them are used in the same receiver the jack most commonly employed Is the double circuit it Is placed between the successive steps of audio frequency amplifiers and when the telephone plug Is removed from it tl e next tube Is automatically connected the double circuit jack has tour four springs which are insulated from each oti ON er and from the arime normally with no plug in it the inner springs press against the outer ones in the better jacks silver tips are used at the point of contact when the phone plug Is inserted the inner leaves are disen and the tip of the plug makes connection with the lower outer spring while the sleeve touches the upper outer one the single closed circuit jack jack has only one outer and one it irner ner spring the tip of the plug touches coll coil condenser wave trap Is simple affair wave traps are by no means new for several years ears they have been used in various ways but curiously enough few broadcast listeners have made use of them to eliminate the most frequent interfering conditions A wave trap Is a simple affair con of a variable condenser in shunt with a coll coil of suitable size and the whole connected in series with the aerial wire leading to the tuner of the receiving set when this trap Is turned it weeds out the undesired signal cirp C irp should be taken in its construction to keep the resistance at low value ot berwise the sharpness of tuning of the trap will be adversely affected and the signal strength will be lessened the size of the coll coil depends on the waves to be eliminated thus for meter trapping a 35 turn coll coil will be found most effective while for ex eluding n eter stations a 75 turn coll coil Is necessary the variable con denser should have an approximate capacity of microfarads which Is the general equivalent of a 43 plate condenser the manipulation of wave traps Is as simple as their construction it if while listening to a meter station inter TRAP terence ference Is noted from a meter sta tion the short circuiting switch on the trap Is opened then the condenser Is turned until the interfering signal dig dis appears once this Is done it will be necessary to the receiver as the characteristics have been considerably i altered by the adjustment of the tuned circuit in the aerial wire radiophone proves boon to lighthouse keepers radiophone communication between light stations in isolated territory has been found very successful by the lighthouse service according to re ports to the department of commerce complete stations were installed at cape Sa richet and scotch cap light stations at alaska aska in 1921 and after overcoming some difficulties of opera tion during the first ye ir due to burn outs of the motoi generator and wreck ing of one of the steel antenna masts by a storm communication between the stations has continued the two stations are about seven teen miles apart keepers at both sta eions have mastered the code so as to be able to ex exchange chane messages with mall mail steamers and have been able to communicate for a distance of 65 miles by voice and miles in code the telephone installation at these stations consists of a type 0 W short range radio telephone set two three fourths X W 32 volt delco en gine glue driven generators two 70 foot steel poles and the an antenna and ground system the up lip of tl it e long spring wl lie ile the sleeve connection Is made directly on the brass frame the single open circuit model ie Is similar automatic filament jacks have extra sets of springs to control the battery circuit of the tubes when properly wired the tubes will be all out when all the jacks used are empty even though the rheostats are turned on when the phone plug la is inserted only the tubes up to that jick are lighted and no others when the plug Is removed the entire set goes dead the wiring of these filament flIam ent jacks Is rather complicated but tl ey are so ent ent that the trouble Is well worth while there are only two types s sin gle and double circuit the double one Is similar to the regular single closed circuit one and the single circuit Is like the single open circuit regular model the symbols used to represent jacks in diagrams are practically pic pie tures of them so they are rather easy to follow new york globe an upright aerial for inside or outside use an upright aerial of the type shown in the drawing drawl Is a worth while adal tion to any tiny receiving or transmitting set and Is particularly convenient where but little space Is afforded for the erection of an antenna system when used outside it cannot be wae mast S 9 L A an aerial of thie this type Is satisfactory for both reception and transil Tran smie G elon slon purposes it Is very conven 1 lent where space 1 Is a factor knocked down by heavy storms espe dally during the winter inter months when ice covers the wires and gives them additional weight it Is well known that a vertical aerial Is the best type of collective agency that can be used in conjunction with a receiving set and la Is also well adapted for transmits tran slon sion purposes it has ca opacity due to the fact that it Is corn com posed of a number of wires in close proximity to each other this type of aerial Is very easily constructed consisting simply of two bicycle wheels bolted at tl ti air centers to a wooden or bamboo pole of euffe dent clent diameter to guarantee stability the two bicycle wheels sl odd orld be mounted about ten feet apart the method of assembling Is clearly ihorn in the accompanying illustration small insulators should be faste bd at intervals along the peripheries of inch each wheel and the wires Rus suspended between them the leadin lead in as sho Is taken from the lower portion of the aerial and led to the set tl tits Is type of aerial can of course be used very successfully indoors iladio news person may listen and converse at same time conversations are being held dally over the volt keokuk dam data cables between the I 1 age avenue sub station of the union electric light and an power con pan st louis and the st charles wo substation by means of a blied wit ed wireless w system per fectea by roy L glasgo v assistant professor of electrical engineering at washington university st louis the apparatus appa ralus devised by I 1 ro fessor glas gow comprises a duplex system whet e by two transmission wires are so used that a person may talk and lista n at the same time using an ordinary telephonic ir transmitter and receiver an I 1 a delicate relay system by wl ich fell the in incoming conling impulse switches in a local current to ring a bell or light a lamp as a calling signal the transmission on set uses two five watt tubes wl es at each terminal are stretched about feet parallel to the pow power er c bibles ib les A feature of the relay system Is a resistance si of 2 ohms |