Bell telephone magazine (1922) (14776087573)

Identifier: belltelephonemag17amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive



Text Appearing Before Image:
ies planes soon gave way to engine-driven generatorswhich, in their turn, were replaced by increasingly dependabledynamotor units. Hundreds of flights were made for accumulation of data re-garding limits and qualities, varying according to times of day,season, distance or altitude, of transmissions to or from theplanes. First studied was obviously the beacon broadcastband (220-390 kcs.), used at once in practical ground-to-planeone-way application. Next came attention to the medium fre-quency band (2600-6500 kcs.) allocated for two-way com-munication, and then portions of the ultra-high radio frequencyspectrum for pure research in the earlier period and latterly fordiverse aircraft purposes as assigned by the Federal Communi-cations Commission. In every investigation, models of newly designed electricaland mechanical equipment were assembled, installed, tested,changed, rechecked, and then given reasonable airplane life-test by the pilot alone or with the cooperation of an observer. 84
Text Appearing After Image:
Literally a Laboratory ix the Air: the Interior of the Ford Plane Durixo Early Tests (in1929), Showing the Laboratories First Modern Receiver and Transmitter in Operation in theForeground, While Measurements of Field Strength of the Associated Ground Station Are inProgress Beyond. The Pilot and Co-Pilot Are Just \isible at the Controls.