INDUCTANCE COILS

Evening Post, Volume CVI, Issue 126, 24 November 1923, Page 22

INDUCTANCE COILS

"Inquirer": Honeycomb coils are quite suitable for use in. either. a' crystal or a valve set, but for short-wave work have no appreciable advantages over cylindrical ,coils. Many amateurs declare that they get their best results with spider-web or-,;basket coils. The honeycomb type shows itself .to best advantage in long-wave work because a great number of turns is accommodated in small space without involving much internal capacity. "Inquirer" says he intends to change from a crystal set to a valve, and asks, if three honeycomb coils will be of any use in a crystal set (presumably . intending to make his set suitable for changing'over)^ As he will need, a 'primary and a secondary ■ tuning ■ condenser for use with the . valve. . in 1 a three-coil arrangement, his best plan is to fit these and take the secondary leads to the crystal detector, and leave the third coil mounting "dummy" in the meantime. He could, however, defer installing one of the condensers and connect two of the coils in series, when they would act as a variometer. Whether this would give the necessary tuning range to include the wave lengths he wants will depend on the dimensions of the coils.