Table 8-2 provides a summary of the properties of the two systems. This 

 includes transducer dimensions and frequency, parameters of the two 

 receivers, and typical pulsing schemes used. Additionally, the last two cate- 

 gories show the orientation of the two systems (horizontal or vertical profil- 

 ing) and the goals of each mounting arrangement. 



Table 8-2 



Overview of the 600-kHz and the 2.4-MHz Systems Used During 



SUPERTANK 





600-kHz System 



2.4-MHz BB-ADCP 



Transmit Frequency 



614,400 Hz 



2,457,600 Hz 



Transducer Diameter 



10.16 cm 



3.175 cm 



Transducer/Receiver Bandwidth 



70-80 percent 



7-8 percent 



Resolution (Sampling) 



0.16 mm (5 MHz) 



20 mm 



Resolution (Filtering) 



1 .6 mm (500 kHz) 



40 mm (20 kHz) 



Resolution (Transmit pulse) 



2.5 mm (2^) 



5 mm (16/4) 



Minimum Operating Distance 



0.50 m 



0.25-0.3 m 



Typical X-mit Pulses 



a) 2.5 mm (minimum) 



b) 8.5 cm 



a) 5 mm (minimum) 



b) 50 mm 



Vertical Operation 



a) Intercomparison 



a) Velocity profiles 



b) Monitor sediment 

 suspension 



Horizontal Operation 



Model transmission 

 losses 



not used 



Experiment Procedures 



Sequence of events 



Data collection was normally initiated 30 to 60 sec before the first waves 

 became apparent in the velocity data. In a standard run, data were collected 

 with both instruments and in several different configurations. Only rarely was 

 a continuous record collected for the full duration of the run. In most cases, 

 data collection was stopped in the middle of a run and the carriage realigned 

 with another offshore instrument group. Data recording was normally moni- 

 tored continuously during the run. 



144 



Chapter 8 ADCP Measurements at SUPERTANK 



