272 BELL SYSTEM TECHNICAL JOURNAL 



section of a simple band-elimination filter, it was possible to transmit 

 and receive simultaneously on frequencies differing by only five 

 percent. 



The equipment at the fixed transmitting location is shown in 

 Fig. 13. 



The car was used for communication at distances up to about 5 

 miles from the fixed transmitter and up to a little over 3 miles from the 

 fixed receiver. The circuit from the moving car to the fixed receiver 

 was consistently good for distances up to about two miles. 



