| Show tuning coil slider gives fine results result S A tuning coil slider which will appeal to many an I 1 one that will come within the ability and means of the amateur was recently worked out it ches one fine results and Is made on novel lines A wire helix takes the place of the ordinary coll coil slider over which it has bag several outstanding merits firstin Fir first lt Is cheap and simple as corn com pared with ith the assemblage of reds standards springs contacts etc in evolved in ordinary slider construction second it produces its shifting of the contact point by a rubbing contact parallel with the turns of the wire in wire replace rod and slider stead of across them so to that it avoids the common tendency to drop in between two adjacent turn turns it Is possessed hessed of a smooth movement instead 0 of a chattering movement and does not wear off copper particle particles which short the tb adjacent turns third the fact that it works by rotation permits operation by a neat rotating rod on one end of any de do tired aired type the contact Is a straight line traverse parallel to the axil Ws of the cylinder I 1 n der along which line the insulation of the wire must be removed in the usual manner hold bole in the coll coil end plates so that the bellr Is somewhat prong sprung against the coll coil making good contact the straight end ends should be of appreciable length in relation to the helical portion to facilitate this springing the helix should be about SW degrees degree five sixths of one turn tum one eight inch diameter brass wire Is about right for four inch length of the wound portion of a coll coil for longer coll coils heavier 1 wire Is better 0 delfs and nt tOlk mil and radio baws I 1 |
