Sample of loading coil for Dover - Cap Grisnez submarine telephone cable, 1910
- Measurements:
-
overall: 987 mm x 70 mm diameter, 1.5 kg
- Materials:
- copper (alloy) and gutta-percha
- Object Number:
- 1953-114/1
- type:
- coil
Sample of Pupin loading coil for Dover - Cap Grisnez submarine telephone cable, probably made by Siemens Brothers and Company Limited, Woolwich, 1910.
The Dover to Cap Grisnez telephone cable was the first cable between England and the Continent to use loading coils. These were used to 'load' the cable with additional inductance to balance the greater capacitance caused by the cable's immersion in seawater. By doing so they reduced the capability of the cables to store electric charges, a problem which had meant that earlier telephone cables struggled with satisfactory speech transmission.
Presentation case for sample of Pupin loading coil for Dover - Cap Grisnez submarine telephone cable, unknown maker, England, United Kingdom 1910