Telegraph, Coherer

grabcad

Wireless Telegraph / CohererThe coherer was radio signal detector used in the radio receivers during the wireless telegraphy era at the end of 19th century - beginning of the 20th century.This design is not based on any specific model, but incorporates all the elements present in the device, both functional and in shape. It is using coarse iron shavings, similar to what is known as "iron boring" coherer.One special feature of old thumbscrews is the "rope" knurling and to emulate it I've made custom knurling wheels, heat treated D2.The coherer is made out of mahogany, brass, bronze and steel with all parts custom made. The bobbins are boxwood and the magnet wire is original silk insulated wire that is over 100 years old.