1072 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1952 



40 



O 15 



10,000 

 5000 



2000 



1000 



500 



200 



CO 

 100 H 



H50 



20 

 10 

 5 



100 150 200 300 400 600 800 1000 1500 2000 3000 5000 



FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 3 — Transmitter power at antenna input required for urban and suburban 

 coverage. (Mobile antennas are assumed to be quarter-wave ships.) 



A word of explanation is needed at this point about the gain antennas 

 which were assumed in one of the curves of Fig. 3. These are antennas 

 which tend to concentrate radiation toward the horizon in all directions. 

 Limits for the amount of gain were based upon the considerations (1) 

 that a set of radiating elements greater than about 50 feet in extent 

 would be impractical to build for this service, and (2) that the vertical 

 width of the beam should not be less than about 2 degrees in order that 

 valleys and hilltops will be covered. The amounts of gain possible within 

 these limits are as follows: 



The mobile antennas were assumed to be quarter-wave whips or the 

 equivalent. 



