The radio dealer (Apr-Sept 1922)

56 THE RADIO DEALER July, 1922 What the Manufacturers Are Doing Combined Receiver Hook and Switch The Universal Radio & Manufacturing Company, 1809 Carter Avenue, New York City, has a new safety device for vacuum tubes which deserves special merit for its simplicity and adaptability in operation. It is a receiver hook and vacuum tube switch combined. When the phones are lifted from the hook (same as ordinary telephone) the tubes automatically light, and are extinguished when the phones are replaced on the hook. The " Hookswitch " is screwed under the edge of the radio table in an inconspicuous place where meddlesome hands will not touch the phones and both are invisible to the eye but within instant reach. According to the recent announcement made by Chas. Skliar, general manager of the company, the " Universal " Variable Condenser both 43 and 23-plate has " passed the test " and is now ready for distribution throughout the country. Radio's Geniuses Busy Manufacturer, Earl C. Hanson, Always Inventing The radio business is rich in talent. Take Earl C. Hanson, technical expert of the Globe Phone Manufacturing Company of Reading, Mass. He is the inventor of the only instrument for deaf mutes embodying the vacuum tube amplifier; he has invented a method of locating faults in street lighting, power mains, submarine cables and the like, and now he hasdemonstrated in New York harbor the practicability of guiding steamships through the densest fog by electricity. After the demonstration the United States Government installed the device under contract with Mr. Hanson's backers. Mr. Hanson, who is only twentynine, is the technical expert of the Globe Phone Mfg. Co. He constructed for the town of Reading an apparatus for locating trouble in their street lighting system. It was only an experiment, but it was a success. The equipment consisted of a water-proof coil, mounted on an automobile and connected to a vacuum tube amplifier. The feeble magnetic energy received from the electric circuit along the highway was amplified sufficiently to permit the " trouble man " to detect accurately the leaks, grounds or breaks in the circuit. The coil on the machine was rotated to more accurately explore the faults, and in the case where trees were grounded to overhead wires, a small hand exploring coil was used. The equipment can be used more specifically, for in case there are several trees in the vicinity of the suspected ground, the tree that is actually in contact with the overhead wire can very easily be picked out of the group by means of the hum heard in the telephone receivers when the coil is near the grounded tree. In order that the " trouble man "■ can be in a position at all times to detect the hum from the wires, and distinguish it from other possible noises, a small instrument placed in the power house is used to produce an absolutely distinct musical tone in the telephone receiver. Mr. Hanson's greatest is the Audio Grebe RORD Two Stage Unit The Grebe Unit RORD, depicted here, is a combination of a detector and a two-stage amplifier unit. It is provided with an external detector jack by means of which the two stages of amplification may be used with an external detector circuit. This type may be used successfully with any type of receiver and is especially adapted for use with the Grebe Type CR-3. The RORD unit, with two special telephone plugs, retails for $75. Manufactured and distributed by the Grebe Radio Corporation, Richmond Hill, Long Island, N. Y.