AIRWAYS COMMUNICATION SERVICE 803 



commercial pilots can be made into good telegraphers and vice versa. 

 For long distance over-sea flights and for expeditionary purposes the 

 radio telegraph has, without doubt, preponderating advantages of 

 longer range with the same transmitter power and of intelligibility 

 through a higher level of interfering signals and acoustic noise on 

 board, aside from its convenience in communication enroute with 

 surface vessels. For regular service on established airways, however, 

 the telephone is undoubtedly superior. 



The perfection of facilities for communicating weather and landing 

 information to planes in flight, which will enable them to operate with 

 safety under relatively unfavorable meteorological conditions, will 

 greatly stimulate the demand for improved aids to navigation. It 

 seems to be established that flying under conditions of poor visibility, 

 when landmarks are totally obscured and beacon lights are useless, 

 requires some form of radio goniometry if the pilot is to find his way 

 through. 



A number of systems have been proposed for this purpose. The 

 London-Paris Airway is equipped with radio direction-finding equip- 

 ment on the ground by means of which the position of planes can be 

 determined on request. The disadvantages of this arrangement lie 

 mainly in its relative slowness and its lack of traffic capacity. The 

 radio beacon of the type being developed by the Bureau of Standards, 

 giving an equi-signal zone which can be observed by the plane, is 

 free from these objections. It is, however, subject to the disadvantage 

 that it indicates a straightline course which cannot always coincide 

 with the airway and is of little value if detours are required to avoid 

 storm centers and foggy areas. 



Another system, a recent development of the British Royal Air 

 Force, employs a rotating loop transmitter at the ground station and 

 indicates the bearing of the plane with respect to the transmitter by 

 means of a special stop watch. This system is relatively slow but 

 permits the pilot to navigate as he would if one or more beacon lights 

 were visible. All of these various methods of goniometry have special 

 advantages and disadvantages, and occupy more or less of the valuable 

 and restricted ether space. The evolution of the system which is 

 most satisfactory will be a matter of time and will require close co- 

 operation on the part of all factors in the industry. 



Bell Telephone Laboratories, at its radio station at Whippany, 

 New Jersey, has erected an experimental two-way radio-telephone 

 system and radio beacon. In connection with this apparatus it 

 utilizes a Fairchild Cabin Monoplane with Pratt and Whitney wasp 

 engine. The plane has been carefully bonded and shielded and is 



