Abstract: A container is provided for retractable measuring tape rulers, wherein the tape is wound around an internal spring and the tape is pulled from the container for the desired length of the measurement. A novel flexible wiper flap is provided at the opening of the container, to prevent dust and contaminants from entering the interior of the measuring tape container and causing damage to the tape itself. The wiper flap is insertable within a grooved recess within the container, and the wiper flap extends down and is flexibly urged against the surface of the tape. The measuring tape is urged into a bowed configuration, so that when extended the measuring tape extends in a semi-rigid fashion during measuring. The wiper flap is also bow shaped at the bottom, and the wiper flap extends down from a tongue coupling portion insertable within corresponding longitudinally extending receptacle portions of the container.

Abstract: A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).