A beacon that flashes a characteristic signal by which it may be recognized
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EMISSION SPECTROMETER
Works on the basis that atoms of metallic and other particular elements emit light at characteristic wavelengths when they are excited in a flame, arc, or spark. Excited light is directed through an entrance slit in the spectrometer. This light penetrates the slit, falls on a grate, and is dispersed and reflected. The spectrometer is calibrated by a series of standard samples containing known amounts of the elements of interest. By exciting these standard samples, an analytical curve can be established which gives the relationship between the light intensity and its concentration in the fluid.
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HARMONIC
1. A sinusoidal quantity having a frequency that is an integral multiple of the frequency of a periodic quantity to which it is related. 2. A signal having a frequency which is an integral multiple of the fundamental frequency.
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HAZE
Fine dust or salt particles in the air, too small to be individually apparent but in sufficient number to reduce horizontal visibility and give the atmosphere a characteristic hazy appearance which casts a bluish or yellowish veil over the landscape, subduing its colors. This is sometimes called a dry haze to distinguish it from damp haze, small water droplets or very hygroscopic particles in the air, smaller and more scattered than light fog.
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HOP
Travel of a radio wave to the ionosphere and back to earth. The number of hops a radio signal has experienced is usually designated by the expression one-hop, two-hop, multihop, etc
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HOMING
Navigation toward a point by following a signal from that point. Radiobeacons are commonly used for homing.
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INTERNATIONAL CALL SIGN
An alpha-numeric symbol assigned in accordance with the provisions of the International Telecommunications Union to identify a radio station. The nationality or the radio station is identified by the first three characters; also referred to as call letters or signal letters.
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BEAT TO QUARTERS
Prepare for battle (beat = beat the drum to signal the need for battle preparation)
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INTERROGATING SIGNAL
The signal emitted by interrogator to trigger a transponder
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INOPERATIVE
Said of a sound signal or radionavigation aid out of service due to a malfunction
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FLAG HOIST
A number of signal flags strung together to convey a message.
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