DEVELOPMENTS IN SHORT-WAVE DIRECTIVE ANTENNAS 661 



service, the antenna should be sufficiently broad in its directivity to 

 include most of the directional variations in signal arrival that may be 

 encountered. In such cases, we have adopted the policy of simultane- 



Fig. 3-A- — Comparative directive diagrams of a high and a low angle antenna. 



STATION GBS X= 16.38 M.NOV. 18,1930 



16:00 

 GM.T 



I8-00 



14.00 15 00 



Fig. 3-B — Comparison of signal outputs of a high and a low angle antenna. 



ously comparing the signal outputs of various size antennas through 

 the measurements of automatic signal recorders over long periods. 

 A photograph of one such signal recorder is shown in Fig. 4. 



Several of our test antennas have proved to be too sharp. On occa- 

 sions, their output exceeded that of any of the smaller, less directive 

 antennas, but when averaged over long intervals of time, they proved 

 to be deficient. At first, we tried to avoid putting too much weight on 

 gain data obtained when signals were normally very strong but long 



