Aerial Laboratory

Radio Record, Volume III, Issue 26, 10 January 1930, Page 10

Aerial Laboratory

An American Innovation ‘A HUGH "telephone booth on wings" has been added .to the equipment ' of the Bell. Telephone Laboratories, of "iNew. York. It.is.an all-metal, tri"motored monoplane equipped. with unGque. apparatus. for. testing and improving. radio: ‘telephone instruments ‘and methods. designed for the use of _ transport and air mail pilots. . In place of seats the fourteen-pas-senger cabin contains two long laboratory benches and a: "wide variety of ‘antennae, On the top of the fuselage, two: stream-lined vertical rod antennae _-are.mounted, Besides there are two "trailing wire antennae and. several tip supports for yarious addition_al experimental , aerials... The metal "*plane itself acts: ag a counterpoise ground. To supply electric current for the »mid-air ; tests batteries and generators are carried aloft. Some of'the geuerators are run .by. the engines of the *plane and others are wind driven. All .. metal parts of the machine-are bond"€d ‘or electrically connected, and all ignition wires and spark plugs are _ carefully shielded. to, minimise inter- . ference, An intercomminiieation telephone system is one of, the unique features "of the aerial laboratory. It enables ’ experimenters in, different parts of the _ *plane to talk to each. other .by. *phone ‘as. well as to converse. with persons ‘on the ground... Besides testing the "Jatest advance in ‘two-way. radio tele"phone equipment, the ’plane will be _- used to measure the.strength of radio waves at different:altitudes under vary‘ing weather conditions and above different kinds of territory. A midget radio head telephone re- *: said to be the smallest in the "world, was used by the pilot of the "plane, in one of the first tests. This ‘tiny instrument is designed to. fit into "the ear channel, of which it conforms »¥n shape. . ‘A A smaller . a four-passenger "cabin monoplane, . -was.previously used ‘> by. the laboratories n-similar experi- = ments. The new machine will allow more extensive tests. Two-way radio telephone systems have been: used: on the London-Paris passenger *planes* for.:some time and have been adopted by several. Ameriean transport companies. They allow the pilot to’ keep’in..constant touch with the ground and. +0 receive detailed weather reports*-as he flies. A new lightweight set, which is installed in the tail of a *plane, ’ ‘has: recently. been given successful tests:on the Transcontinental Air Transport machines. Conversations:.are- said te have been’ held with points more. than six ,hundred miles away. i Me,