34 



TRANSMISSION EXPERIMENTS AT ANTIGUA, WEST INDIES 



time iiidicnteil tli(^ lowest iiv;iil;iljlc antenna height slability of tlic S-band niagnetrou. The receivers were 



on X banrl ga\e the strongest signals. All antennas ealil)rated with standard test sets before every run 



were mounted on swivels to allow alignment on any and checked npon the completion of each test. Indi- 



coursc over a 40-degree arc and were connected by wave vidual calibration curves were then used in plotting 



guide and stub-supported coaxial cable. the results of each run. Since only two receivers on 



Two S-band and two X-band receivers feeding each band were available, an r-f switching arrange- 



20 



40 



60 



80 



100 



Figure 1. S-band run out, March 19 to 21, 1945. Signal strengths of various antenna combinations compared to free 

 space level. 



Esterline-Augus recording milliammeters were kind- 

 ly furnished by the Eadiation Laboratory. The S- 

 band receivers had a minimum sensitivity of 110 db 

 below 1 w, while the X-band receivers had a mini- 

 mum sensitivity of 105 db below 1 w. It was necessary 

 to use automatic frequency control on the X-band 

 receivers, but manual tuning was employed on the 

 S-baud receivers because of the greater frequency 



ment similar to that used on the ship was employed. 



Two-way voice communication between the ship 

 and shore station was maintained at all times for 

 coordination of operations. The facilities of an Army 

 radio direction-finding station on the island were 

 availalde to obtain bearings on the ship. 



Meteorological measurements were made at the 

 shore station during operations by means of kite 



