MINIATURE RADIO SET MADE BY BOSTON FIREMAN—COST 35 CENTS
Novel Installation Size of an Ordinary Dollar Watch—Home-Made Device Works Perfectly He Also Builds a Miniature Steam Engine
FIREMEN at the Mason Street engine house, Boston, Mass., are having much enjoyment as a result of the mechanical genius of James J. Harrington, who has built a number of miniature radio receiving sets with which it is possible to pick up the concerts broadcasted from Station WNAC, the Shepard Stores, Boston, and Station WGI at Medford hillside. The set developed by Fireman Harrington is remarkable for its small size, low cost, and loud quality of tone. The material of which the set is made exclusive of the ear phones costs only 35 cents. The wonderful results obtained from this set, which is small enough to fit in a vest pocket, are due to the manner in which the coil is wound.
Twelve feet of No. 26 wire is wound on a piece of cigar box three-eights of an inch by one-eighth of an inch. There is about one-eighth inch space between each parallel wire and each layer is wound in the opposite direction. The coil is contained in a box 1 1/2 inches long 1 1/4 inches wide, and 7/8 of an inch deep, made of cigar box wood.
On top of this box is the crystal holder which may be bought for 10 cents. This holder is made of fibre and includes the “cat’s whisker” and two binding posts. A third double binding post is placed between the single posts. This costs 10 cents extra. A crystal can be bought for 10 cents and the wiring and loads cost about 5 cents. The coil is connected between the bottom of the crystal receptacle and the ground binding post. The top is then glued or screwed to the box.
Harrington has also built a tiny steam engine with pistons, cylinder, etc., complete in every detail with flywheel to which a small belt can be attached. The machine will run from the exhaust steam of a radiator.
The maker of the radio set and engine served in the naval aviation force during the war with rating of chief machinist’s mate and had charge of the installation of motors in the seaplane NC-4 which crossed the Atlantic ocean. He is now assistant engineer of engine company 26-35. His home is at 19 Rowell Street, Dorchester, Mass.