382 



BELL SYSTEM TECHNICAL JOURNAL 



in which both branches were steered at the same wave bundle. They 

 cover winter and summer and were obtained with frequencies appro- 

 priate to the time and season. Most of the observations were made 

 on transmission from Daventry, the remainder on transmission from 

 Rugby. In D are shown the results of pulse measurements made 

 before the MUSA was ia use. Here the angles were measured by the 

 two antenna null method and the delays were observed directly on the 

 oscilloscope time axis.^ Although as many as five points, each de- 

 noting a wave bundle, are shown, generally not more than three were 



1.6 

 1.2 

 0.8 

 0.4 



I °' 



O 



O 2.4 



LlJ 

 lO 



Ij 2.0 



_j 



2 1.6 



Z 



~ 1.2 



>- 



< 



-1 0.8 



LiJ 

 Q 



> 



K 



< 



UJ 



10 15 20 25 



EARTH ANGLE .6 IN DEGREES 



35 



Fig. 31 — Pairs of measured angles and relative delay denoted by the end points 

 of the line segments. The data in ^, 5, and C were obtained with the MUSA; that 

 of D was obtained by the use of pulses. 



important at once. These measurements were made on transmission 

 from Rugby. 



It will be noticed that all four groups of data show that the relative 

 delay per degree of angle difference is small at low angles and increases 

 with the angle, roughly as the multiple reflection theory indicates. 

 (This characteristic is distinctly favorable to the performance of the 

 MUSA since its angle resolving power falls off at very low angles.) 

 The scattering of the data indicates that an equalizing delay deter- 

 mined by the angle settings would not be successful; i.e., the delay 



