TRANSATLANTIC RADIO TELEPHONY 253 



to place the receiving station in a more northerly latitude, bringing the 

 signals down to the business centers by wire. In order to determine 

 the extent to which this was useful, measurements were made at 

 Green Harbor, Mass., and at Belfast, Me., over a considerable period 

 of time. These measurements were made on telegraph signals specially 

 transmitted by the British General Post Office from its telegraph 

 stations. It was found that in Maine the signal-to-noise ratio was, at 

 least during the important hours of the day, something like six or 

 eight times that which was obtained on Long Island. In other 

 words, the improvement was as great as would have been obtained 

 by multiplying the power of the English transmitting station some 

 fifty times. It was therefore decided to build a receiving station 

 equipped with wave antennas at Houlton, Me. 



These two improvements, the one in the antenna and the other in 

 its location, taken together comprise an astounding advance in the 

 battle against static. To get the same results by increasing the 

 power of the transmitting station while using older receiving methods 

 it would be necessary to employ transmitting apparatus rated at one 

 million kilowatts, a power which is obviously far beyond either the 

 technical or economic possibilities. 



The British Post Office, having in mind that all Great Britain was 

 already more northerly in latitude than Maine, decided to build a 

 temporary receiving station near Wroughton, England, leaving the 

 question of a more northern location for later experiments. 



On both sides of the Atlantic, suitable wire circuits had been 

 arranged to tie the transmitting and receiving stations, to terminal 

 points in New York and London. There were then available early 

 in 1926 the means whereby a complete channel could be set up from 

 New York to London and one from London to New York. These 

 two channels were operated on different radio frequencies, the 

 American transmitter sending on 57 kc. while the British transmitter 

 sent at about 52 kc. 



At this point, with the major radio problems if not solved, at least 

 well in hand, the undertaking became more a telephone toll circuit 

 problem for the time being. The simplest way to connect up a system 

 of this kind is to follow the practice which is employed for long 4-wire 

 telephone circuits. Where the circuit needs to become a 2-wire 

 circuit for termination in an office where it may be switched to sub- 

 scribers, the outgoing and incoming wires are brought together through 

 a hybrid coil or 3-winding transformer. This well-known device, 

 by means of a balancing arrangement, has the property of directing 

 currents incoming on the receiving leg of the 4-wire circuit into the 



