Show 1 i ro swo 4 0 ats w 1 44 edited by 0 Dou dougla irlas lv ardro editor 0 of f radio cadlo liOng here Is a simple vernier arrangement tor for vario meters and condensers which will be found very convenient in tuning for or OW fig I 1 shows the rubber knob and the binding post from which the tha vernier la Is made almost any type or size of rubber knob maybe may be used the dimensions shown of course will require to be changed accordingly tho knob anoli used measured one halt half inch in diame ter and one half inch deep with a knurled rim three quarters of an inch in n diameter to adapt this binding post face off the one half inch length to one quarter inch and bevel th chef length to an angle of 43 degrees TW can be conveniently done by screwing the knob on a threaded rod which Is put into a collet and turned in a lathe the threaded rod Is an 8 82 32 machine screw with the head bead cut off an 8 82 32 roundhead round head machine screw a one halt half inch spring to pass over the bachl machine 0 n screw and a small brass washer complete the tha vernier A hole Is drilled 4 through tho the panel slightly below the so to 84 v 1 aa TV jg 47 4 dial of the varl ometer to pass the 8 32 machine screw the screw Is inserted through this hole and the spring washer slipped over lt it and lastly the tapered rubber knob Is screwed on it Is preferable to use a machine screw which Is threaded only nt at the end on which the knob Is 14 screwed as aa a machine screw entirely threaded tends to catch in the hole when the vernier la Is manipulated to operate the vernier a slight blight pressure Is 19 applied while turning which permits the tapered periphery ot of the vernier to engage with the rim of the dial enabling a micrometer adjustment how loop antenna can be made by amateurs many amateurs are handicapped in their erection of an antenna by lack of space A loop aerial as shown in the diagram can be constructed and will obtain very good results with one vacuum tube detector to construct this loop two laths baths of wood SS 25 binche a long should be obtained A notch Is cut in the center of each and they are joined together to form an X four laths baths of wood each IS 18 inches long are nailed across the extremities baw es of the cross supports to form fima a square commencing 31 inches from tb the center saw cuts cuta 4 inch apart are made on both edges of the cross support beginning at the th first or inner beaw aw cut no 22 wire Is wound tightly in a clockwise direction to the outer cater edge the tha loop la Is then turned over and the wiring continued in an anticlockwise anti clockwise direction back to the firra saw daw cut on the opposite side two binding posts are fastened to the cross supports tp to which the ends of the wire are arc connected A strip of oc wood Is fastened across the two opposite legs of the cross croiss supports A hole la Is bored 0 corresponding size alze in the ci center anter of the bottom protecting piece and nd a dowel Is inserted to permit the loop to revolve trouble in adjusting secondary condenser Con denaer while tuning in phone signals and OW CA considerable trouble in adjusting the tha ne oe condary condenser 1 Is often expert experienced encee the following is if a method dented ano and used with good re lulls take nn an ordinary 43 wate condenser cond ner out of its tt casing and mount a large gear wheel on its shaft the condenser in turn Is 1 mounted on the tha back of the receiving panel tn in ithe usual manner with them the exception that no ao hat abaft protrudes A small mall near gear wheel li Is mounted on ft a brams shaft and fitted through the parel par el 0 so o as to mcash with the tha large tear gear alila abaft may be centered on the cover of th co ademer or other arrangements made for its reir rear acting ni As front bearing upon this shaft a 3 dial and knob are attached at the present stage it may be used and an adjust meat of 5 to I 1 secured cured te the gears his may be obtained from a telephone bell ranger which serves the purpose ad owing to the numerous teeth on the gears bears for much finer adjustment another shaft in vertical line with the condenser and dial centers may bo be fitted upon which la Is mounted 4 piece of rubi rub i her ber packing in such a manner ns as to bear friction against the under side of 0 the dial A small email binding post knob is 3 attached to ON shaft which further allows close adjustment similar to the vernier attachments attach menla on the market today the dial will turn several times aft abc before the condenser has made halt hall a revolution and in order to know how your condenser la Is setting a ISO degree scale Is mounted on the law large cog wheel and nn an opening cut in the panel to view the scale the illustration boaks tills this description clearer and from tho the general plan the amateur may devise his him own means for mounting the gears and condensers he be may have on hand vernier adjustment to be used on dials A vernier adjustment to bo be used on the dials of condensers may be easily mads made with the following parts three inch rod three quarter inch anch rubber stopper knob to fit on rod cull cuff to ht rod the rod li Is set out about three inches from the ho front of the panel which assists in eliminating we hand band capacity ole bach ruff W a J stopper effect when tuning for OW the rod passes through the panel and Is in seated in a hole bole at the back of the cabinet the cuff on an the lie roil rod la Is brought close to the back of the panel the rubber stopper Is cut in half and a bole drilled through the middle the rod Is passed through with the larger end 0 of the stopper towards the panel the tha ulal dial bears against the tapering rubber make safety pin work as crystal detector the clip is made of brass 10 to IS 18 gauge about A inch wide by 2 binche j long cut as per fig 2 instead of using a brass clip a test clip will do to hold 0 the crystal the rod b Is a ca s 6 wooden rod such as Is used vy the butchers to hold meat together the safety pin Is oland to tho the rod with a hole bring drilled for the roil rod no dimensions are given as ai this Is leto left to the experimenter and whatever mst ma be has on hand band ah 0 IF SHORT CIRCUITS i 4 when a set has just been wired and Is being tried out if a steady hum to ti heard la in the phones this will tell ot of an open circuit scrape the tha of the crystal and leave the scrap pings on the crystal the has hac then only to bt b placed on any point and a sensitive ban spot will be found when the station desired ti Is tuned in why not assist aalst your neighbor to get the he same game station by stopp stopping lne your tube from oscillating lc will found better anyway in wiring your net met it la in bet beat to use no 14 or 16 B and S ropper waro in IB close wiring co wires with cambric or spaghetti ettl tubing round hound or square tinned copper makes the th neat beat est job dont varnish coll when winding a coll coil for radio use avoid putting paint varnish of if shel hel lacon tho tha to hold them la in place A drop of nealene wax around the outer edse edge will trill do ali trick anti Is much better |