Show tuning coil slider u gives fine results AA A tuning coll eoll slider which aich will appeal to many and one that will come 1 within the ability and means of the amateur was recently worked out it gives fine results and ls lb made on novel lines A wire helix takes the place of the ordinary coil slider over which it has several outstanding merits alist ali st it Is cheap and simple as corn com pared with the assemblage of rods standards springs contacts etaf et 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 4 1 wire replaces hod rod and slider ite stead of across them so that it avoids the common tendency to drop in be tween two adjacent turns it Is pos se sensed b sed of a smooth moy movement ement instead of ota aa chattering movement and does not wear off copper particles which sl ort the adjacent turns third the fact that it works by rotation permits operation by a neat rotating rod on one end ot of any de sired tape the contact Is a straight line trav erse parallel to the axis of the cl inder along alich wl ich line the insulation of the wire must be removed in the usual minner mount blount through holes in the coil end plates so that the helix is some vl 1 at sprung against the coil mal ing good contic t the straight ends sl be of appreciable length in relation to the hel cal eat portion to facilitate tt it is springing the helix should be about AW degiers ea eps e s s of 1 one ne turn urn one eigl elgi th inch d ameter br ss wire 19 1 about rigl t for foul inch length of the w aund p artl n of a coll coil for longer coils oils heavier wire is better 0 o science and invention and radio news |