Coil used to fine tune the primary oscillatory circuit of a spark transmitter. It was also referred to as a strip jigger in the early days of radio.

Physical Description

Open spiral wound copper strip on a varnished wooden board. There are two terminals, one connected to outer end of the spiral. The other terminal would have a lead terminated by a clip, which is placed on the spiral in a position to tune the aerial; the lead and clip are missing.

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