. QST . OUT Whenever an amateur designer tackles the job ofputting together a Pi antenna coupHng net-work, he runs into the problem of getting a widecapacitance tuning range on the antenna sideof the circuit. The usual method of assembling a decade groupof 10 mica fixed capacitors and a selector switchis not nearly as siinplo as it sounds. First, itrequires 10 capacitors . . which take a lot ofspace. And second, getting these units arrangedinto a compact, short-lead pattern is far from easy. Here is what radio experimenters at Mallorv didto lick the problem. Instead of 10-unit decades,thev bui
. QST . OUT Whenever an amateur designer tackles the job ofputting together a Pi antenna coupHng net-work, he runs into the problem of getting a widecapacitance tuning range on the antenna sideof the circuit. The usual method of assembling a decade groupof 10 mica fixed capacitors and a selector switchis not nearly as siinplo as it sounds. First, itrequires 10 capacitors . . which take a lot ofspace. And second, getting these units arrangedinto a compact, short-lead pattern is far from easy. Here is what radio experimenters at Mallorv didto lick the problem. Instead of 10-unit decades,thev built a capacitor decade with only fourcapacitors . . bv using a Mallory Type 1S3LSwitch. Tvpe MC SOO volt mica capacitors, withvalues of 100, 200. 300 and 400 mmfd. are con-nected to the switch in the reconunended the switch is rotated, the capacitors are auto-matically connected in single and parallel arrange-ments to provide ten steps of 100 mmfd. each,plus an off position. If voure not fam
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectradio, bookyear1915
