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1. Abbr. for daylight factor.
2. On drawings, abbr. for drinking fountain.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
DF (direction finder)
A radio receiver equipped with a direction-sensing antenna used to take bearings on a radio transmitter. A direction finder essentially consists of a loop aerial. To remove 180° ambiguity, a sense aerial is also brought into the circuit. The DF system can either be airborne or ground-based. See automatic direction finder.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved