Tune Indicator - AWA, Spark Transmitter, 1914-1920 Object Reg. No: ST 021422

Tune (tuning) indicator: a lamp is connected to one end of a loop of wire and a adjustable tap. The loop is placed in series with the earth lead of the jigger secondary coil, and the tap is adjusted to give a reasonable brightness at maximum antenna current. Other positions might lead to bulb burn-out or the lamp being too dim to observe the light.

The lamp indicates by its brightness the current in the aerial circuit, which is adjusted for a maximum by varying the tuning inductor (jigger or spiral inductor).

Tune indicator ST 021416 achieves the same result as ST 21422 but in a different way.
Varnished wooden board with an approximately 270 degree arc of wire connected to two terminals. A wiper arm, fitted with a knob, is connected one side of a lamp socket; the other side is connected to one end of the loop. The globe is missing.
Acquisition Information:
Donation from Amalgamated Wireless (Australasia) Ltd., 1940
Discipline: Technology
Dimensions: 55 mm (Height), 150 mm (Width), 153 mm (Length)

More information

Tagged with: radios, electrical components, resistors
Themes this item is part of: Information & Communication Collection, Radio from sparks to valves, 1914 - 1920
Primary Classification: COMMUNICATIONS
Secondary Classification: Radio
Tertiary Classification: transmitters
Manufacturer: Amalgamated Wireless (Australasia) Ltd., Sydney, New South Wales, Australia, 1914-1920

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