A STATEMENT from the office of the United States Naval Communication Service says that the attention of all ships navigating in the vicinity of Point Judith, near Newport, R.I., is invited to the recent installation at Point Judith Light of a radiophone fog warning device.
The apparatus will be of use to commanding officers in picking up the light in thick weather, as experience has shown that operators can judge to some extent the distance according to strength of signals with a known normal range. Although measurements have been taken to determine the limit of the range of this apparatus, too much reliance should not be placed in it until its worth has been proved under service conditions.
The apparatus will be in commission beginning about October 1, 1917, and will be in operation during fog, mist, rain and falling snow. The warning consists of the repeating of the words, "Point Judith Light," every five seconds, with limit of range of about eight miles. After every third repetition the warning, "you are getting closer; keep off," is sent out with a limit of range of about two miles.
The apparatus required for the reception of the warning signals is an ordinary radio receiver. Crystal detectors may be used. The wave-length is varied continuously between 550 and 650 meters.
It is requested that reports be forwarded to the lighthouse inspector, Tompkinsville, N. Y., concerning the range and value of this fog signal as found by experience under service conditions.
The system is yet in its first stages and it will doubtless be improved in the course of actual practice. The fact has been pointed out that before long every lighthouse will be shouting its name and other information so that the illumination will become of secondary importance. 1
Electrical Experimenter September 1919
1 Wireless Age November 1917
2 Lighthouse Antiques