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Radio Record, Volume I, Issue 28, 27 January 1928, Page 15

Accuracy in the location of holes when drilling a panel can be considerably increased by the use of a centre punch in locating the holes. Use a very light tack hammer and a sharp centre punch. Only a slight tap is needed to form an impression at the exact’ centre of the location of a hole. This serves ag a starting point for the twist drill, which is used later. Best results will be found if the centre punch is held in a vertical rather than a slanting position, since in the latter position there is a possibility of the point skidding and marring the surface of the panel. It is best to place the panel on a sheet of paper when laying out the location of holes, since there is a possibility of the panel hecoming scratched if it is placed on a table top without any protective coyering. The tone anality of the average receiver may be improved to a verv noticeable degree by the addition of an extra loudspeaker connected in series with the one being used. If only a cone speaker is used, the addition of a good type of horn spéaker, connected in series with it, is advisable. and vice versa. The cone is usually an excellent reproducer of the lower frequency or bass notes. "The use of a cone speaker alone does not alwavs permit a full resister of both high and low notes. With the addition of a horn type of sneaker, which has the ability of reproducing the higher frequency notes to an exeellent devree, aA quality of musie will be added which is sometimes lacking in’ the vse of a rone type of speaker alone. To hook ux) the sneakers in series, connect the hlack cord of one to the red cord of. the other, and attach the remaining terminals fo the narmal loudspeaker terminals of the receiving set,