Show use telephone jacks for contact switches another evidence of the cleverness of the radio amateur Is the making of a compact and neat multiple contact switch for panel mounting from ordinary telephone jacks such switches possess the desirable feature of taking up a minimum of panel space are easy of installation and require but ono holo hole in the panel most blost I 1 of the telephone jacks ore are constructed with silver allver t IF or platinum contacts affording very low resistance in order to adapt the jack it Is only necessary to make a plunger of some insulating material preferably of bakelite rod of the approximate dimensions men shown in fig 1 A hole drilled through the plunger as at a and having h a small piece of stiff brass wire inserted in it will prevent the removal or loss of tho the plunger when in the out position the uses to which such a tact switch can be put tire ore manifold the accompanying diagram shows the correct method of connecting it tor for changing the antenna tuning condenser for series or parallel connection although other uses will no doubt suggest themselves to the experimenter A further advance in panel neatness can bo be attained through dl a lumping emping the head of the plunger with lettering corresponding to the use to which the switch Is put rather than engraving the panel surface |