PROPAGATION IN S AND X BANDS IN LOW-LEVEL OCEAN DUCTS 



39 



Measurements on the leeward side of the isUmd were significant radar datum obtained to leeward of the 

 also made with this radar with approximate antenna island was the detection of a ship at 45 miles from 

 heights of 6, 10, and To ft above sea level. 



The maximum range obtained using the PC boat 

 as a target with a broadside aspect was 47 miles. This 



a 75-ft site. 



Meteorological Measurements'' 



range was observed with the radar antenna at the 

 6-ft level. The maximum range obtained on the ship 



The description of the meteorological measure- 

 ments in connection with the experiment at Antigua 



20 40 60 80 100 120 



Figure 6. S-band runs with 4G- to 94-ft"aiitenna combination. 



from the 90-ft level was 26 miles. Sea clutter was 

 found to vary with the antenna height and wind speed. 

 Maximum return of 15 miles on sea clutter was ob- 

 served at the 6-ft level with wind speeds of 20 to 30 

 knots. The maximum range at which sea return was 

 obtained varied proportionately with height up to 

 the 90-ft level. This range was decreased 50 per cent 

 with lower wind speeds of 10 to 15 knots. The most 



is divided into three parts, as follows: first, a brief 

 general description of the West Indian climate; sec- 

 ond, a survey of the low-level soundings; and third, 

 a necessarily hurried analysis of the data, with certain 

 tentative conclusions. 



The most noteworthy feature of the climate at 

 Antigua during the late winter is the persistence of 



•■By Lt. W. Binnian, U. S. Naval Research Laboratory. 



