616 BELL SYSTEM TECHNICAL JOURNAL 



for this service was established near Boston. The necessary equipment 

 for boats was also developed. The fishing boats by means of this 

 service can keep in touch with the fish markets and can take advantage 

 of rises in prices. They also find it convenient for communicating 

 with each other when schools of fish are found and that has also been a 

 help in their operations. There have been a number of occasions also 

 in which it has resulted in the saving of lives at sea, as the radio was 

 used to notify the shore station in case of accident and the shore 

 station called other vessels and sent them to the rescue. This service 

 to fishing vessels was then extended to other coastwise vessels, yachts, 

 tugs, etc., so that there has gradually developed an extensive radio 

 service of this type on both of our coasts. Radio stations are located 

 not only in Boston now but as indicated in Fig. 4 there are stations at 

 New York, Ocean Gate, N. J., Wilmington, Del., Norfolk, Charleston, 

 S. C, Miami, New Orleans, Galveston, Los Angeles (San Pedro), 

 San Francisco and Seattle. Stations are under construction at Tampa, 

 Fla., Astoria and Portland, Oregon. Service is now given to more 

 than 2,000 vessels, there being 200 tugs, 1,100 yachts, 100 steamships, 

 400 fishing vessels and numerous others, police boats, pilot boats, 

 barges, launches, etc. The largest number of vessels so equipped for 

 communication with shore are grouped around New York and San 

 Pedro, there being about 600 in each of these areas. 



In this type of service each shore transmitter and each shore receiver 

 is assigned a frequency. Any ship may provide itself with frequency 

 control crystal elements for communicating with as many of the shore 

 stations as it desires. Coastwise vessels in traveling along the coast 

 may thus keep in touch with their nearest shore station. In New 

 York there are two such circuits provided with transmitters located on 

 Staten Island, and there are receivers located at four places around 

 the harbor for each of the circuits so that the low-powered ship trans- 

 mitters may reach the nearest receiver while the higher-powered shore 

 transmitters reach the ship receivers directly. 



On the United States side of the Great Lakes, connecting telephone 

 companies operate coastal harbor radio telephone stations at Lorain, 

 Ohio, Duluth, Port Washington, Wis., Lake BlufT, 111. and Mackinac 

 Island. 



The use of radio in the telephone system brings forth a number of 

 problems. First of all, to provide a radio circuit for a telephone con- 

 versation there are required two radio transmitters and two radio 

 receivers. The transmitters and receivers must be so located and so 

 designed and operated that one person at one end of the circuit may 

 speak to a second person at the other end and the second one to the 



