Show edited by 0 douglas editor of radio merchandising A t A hookup shown for benefit of non technical layman wiring Is I 1 simplicity itself chances for going wrong aro are minimized by ROBERT LA MAR all molt men tire born free and equal so says the constitution of the united states however Ilo wever the very verv world we live in deales tills this somo some tire rich others ore well on off while the vast majority slave or starve therefore wo we do not spend our money without looking before we leap if you be desirous of purchasing it 11 radio set that will do the work of tit the 0 more costly ones and yet be inexpensive I 1 think I 1 know of the set iset you tire lire looking for the receiver costs tint hilt a few dollars to construct yet operates ns as well ns the best of course it lilay inny not look ns as well as the more expensive sets now for the lie set A few about it wont harm a hit bit in fact they aliey may help materially the receiver Is of 0 the good old regenerative typo type and to be more specific it Is what Is known ns as lie ho ultra hudlon the old yet effi elent means of obtaining regeneration its as discovered by dr lev de forest As few controls as aa be wished tors fon are anre employed to wit vit but one strangely it Is not a condenser it coupler or oven a indeed it Is quite dif different Terent A metal ring strange but true actual results obtained the writer mode it receiver of this type some roine time ngo ago the set met was constructed very poorly connections being and all parts laid on it a breadboard A two stage audio timp amplifier lifler of standard design was connected after it so that the use of head phones might bo avol avoided ded tim tiie log of stations heard after a A A A little hookup sure fire and full of pep few nights looked like ilka a n page torn front from the he telephone directory stations from chicago Cle cleveland canada michigan havana memphis and from places too numerous to mention caroe came in all over oer the room wonderfully well necessary parts parta visit your local radio store and procure the following ono one piece of cardboard tubing two inches in diameter and sk six indies inches long one fourth pound of no 24 D 0 C wire wl re one rheostat one seven seen by ten inch panel one baseboard seven by nine inches one socket one fixed condenser rulen mica of course one variable nr lable grid lenk leak H eight eglit binding posts one fixed condenser one four inch dial necessary bus bar screws and sundries with turns of the lie wire on the coll coil leaving about a half inch from one end before starting to wind do not use shellac lc water glaas sodium silicate or any other liquid to secure the wires if you wind the coll coil carefully there will be no need of the various adhesives an old kink should be remembered rem emberd when winding the ho coll coil that la Is to have the wire pass over a warm stove before being wound on then wind the wire on tightly taking care that each turn Is close to the previous one now anchor the two ends en da with sealing wax next wind fifteen turns of the same size wire on top ot of the turns these turns should bo be wound in the same direction as the secondary daiy and in the center of it this to IB very important por port tant nat procure a piece of thin sheet brass or copper six inches by four bend the brass or gr copper OBI ab the case may ba in ha annn of ailt ft circle using the four inches for the length and the six inches as the circumference clean the brass where the brids meet and with a little solder and somo some paste solder them together you will then find that th circular form will it very snugly inside of the lie coll coil which you prepared but a few minutes ago go then take a piece of brass adv and use it as a crosspiece so that there will be some place for a wooden roil rod to control the movement of this metal cylinder A piece of dowel pin one quarter of an inch in diameter will serve ns its the shaft for the cylinder weve got to mark the panel out so that hat there will be 18 a uniform well balanced panel layout when doing this you will find it best to mount the coll coil at the right center of the panel so that the shaft will project nt at dead centar then mount the lie rheostat a bit below center and toward the right the peep holes for the tube should be marked out above center find and in a line with the shaft for the rheostat drill the panel carefully feeling your way so BO that you will not burr the panel when the drin drill goes through the host bert way to avoid this Is to apply little pressure on the drill and turn it in it a steady fash fashion fas lilon lon mount the coll coil to the panel olt two angle brasses and fix the rod so that it passes through the panel smoothly tighten the four inch dial on the rod so that by pushing it in and out you will bo be able to control the position of the metal cylinder wiring the set the next step would lp be to mount the rheostat binding rests posts and the baseboard upon which be mounted the socket now that everything Is mounted we may proceed with the wiring of the re receiver colver solder a piece of bus bar to the antenna post on tile the set and run it to the beginning of the fifteen turns next continue this connection to the plate of the vacuum tube socket connect a wire aora the plate of the socket to the phone binding post as shown in figure 1 the end of the fifteen turns Is connected to the ground binding pos and to one side of a fixed condenser connect the other side of the condenser to the filament minus run hun it a wire from the beginning of the turns to one side of the lie grid leak and condenser combined the other side of tile the grid condenser dk anser Is r c melted directly in as aa short and direct a possible way to the grid binding post on the socket further wiring now ye we connect the end of the see secondary turn winding to tile the filament plus we have but a few connections to go they are A wire from the remaining phone post to the B plus a wire from the B minus to the A plus the A minus binding post goes to one side of the rheostat the remaining terminal of which goes boea to one of the lie F posts on the socket A wire la 19 then run from the other 17 F post on the socket to the A battery plus well the wiring of the set la Is done it might be wise to recheck your tour connections following either the he schematic diagram of figure 2 or the picture hookup hook up of figure 1 undoubtedly the set bet will work but the signals may be weak if this be the case the lie secondary leads are reversed A transposition of leads lead should settle this trouble in a jiffy jiff Y if the set bursts into oscillation too easily try lower and higher values to bypass by pass condensers from the ground to the filament minus the higher the value the more it will oscillate when the copper or brass ring Is in drawn inside the tube remember it la Is not connected in any electrical way it concentrates the magnetic field of the coll coil when the ring Is slid out of the surrounding field of the coll coil the distributed capacity of the inductance Is increased consequently we are able to tune the set merely by the relative position of a brass ring no condensers conden sora of any kind are used and consequently the efficiency Is kept neap the Ili hundred undred mark new N york tel grain graim |