. Electronic navigational aids; loran, radiobeacon, and radarbeacon systems and loran, radio-direction-finder, and radar ship equipment . Figure 2-11—Weatherproof housing of a modern radio direction finder loop antenna mounted above deck. As the diagram indicates, the minimum is well-defined, and the maximum is not; that is, the strength of the signal varies rapidly with movement of the coil near the minimum, but varies slowly with movement near the maximum. For this reason, the minimum is used in observing bearings. Otherwise there would be important advantages in taking bearings on the maxim
. Electronic navigational aids; loran, radiobeacon, and radarbeacon systems and loran, radio-direction-finder, and radar ship equipment . Figure 2-11—Weatherproof housing of a modern radio direction finder loop antenna mounted above deck. As the diagram indicates, the minimum is well-defined, and the maximum is not; that is, the strength of the signal varies rapidly with movement of the coil near the minimum, but varies slowly with movement near the maximum. For this reason, the minimum is used in observing bearings. Otherwise there would be important advantages in taking bearings on the maximum, in the way of greater audibility and of thus diminishing the effect of interference. In a rotatable coil of practicable size the voltage induced by a radio signal is very small. For the employment of such small coils for radio direction finding purposes it is essential that there be great amplification. The radio direction finder should preferably be installed in a position easily accessible to the ship's navigator. The navigator desiring to take a radio bearing simply closes a switch, manipulates a single adjustment until the characteristic signal of the desired rediobeacon is heard, rotates the radio direction-finder loop until the sound becomes a minimum or is inaudible, and then reads the radio bearing. No knowledge of radiotelegraphy is necessary on the part of the navigator. In addition to the desirability of locating the direction-finding equipment at a convenient location, easily
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