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Show DUNCAN TELLS HOW TO MAKE VARIOMETER i a . 1 Set Should Tune in to 500 Meter Lengths; Enough . for Amateur B R I IH M W Ml - lor. Itndio F llWIr of Anirrn i Having completed the varlo coup-' coup-' ler for the rucn'rAllvo receiving set. get busy on the variometer. Qet a cardboard tube five In. h I In diameter and another four In. -i Cut them down to a height of LWO inches. Heat as you did the varlo coupler and wind with No 24 double OOttOO covered rc-ppfr lr. Leave n spare of about OOO-fottTtb of un Inch In the middle of the windings wind-ings for baft which will be pa- I throuKh ;.itor. Use the aaine number of turns : about 21 on each of the ti be nii4 ! connect as in the diagram one end of the wire on the movable coil k It Inic to one end of the wire on lh' fixed coll. The other endu of Iho ! when ars brought to binding poat'--i i i K Mi ROTOR Th fixvl coll la called the tatdrl and the rnoTable coll the rotor. After the colls are woui'd thy may be given a very light roat of riear rhellac to holJ them In plni e more firmly. L ave enough alack in tha ,:re attaChad to the rotor so that it may! be turned about insldo the stntor. A brusn rod is uso l to UPporl both cniln. When varied, the rotor j should freely To make the connection from Iho; atator to the rotor, punch a am til hole in thfl tube of tha stator and: pusli a fr-.- arlra through. Cbnnel t it to tha wire from tbo rotor allowing allow-ing enough slack for rotation. Put few drop of glue in the hole to bold the wire firm. The other two wires one from the etator and the other from the' rotor may be broush .lov-n alonsf a grooved line in thi: uprighM of the variometer stand one on each upngh. antl thence o the binding f.o"s. In our diagram o. hook up. we showed two variometers. .lake If jH slL . Mator D, Rotor. ' . Kd Ulf. D ETlcxlble Wire. 2. Variometer, ii Binding Hot.. 3, Upright th'ni both us herein described. U'g up the other parts from your old set or build aa aaplalned m previous articles. This set should tune in to approxl-mafaly approxl-mafaly OoO-meter lengths, which ill receive all amateur :nd broadca.s: lng transmission. oo |