210 



TELEMETERING UNDERWATER 



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Fig. 86. Experimental test of sonic telemetry equipment in Little 

 Magathy River, A - s"wimmer approximately 30 ft awray, B - swim- 

 mer approximately 60 ft away 



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Fig. 87. Experimental test of sonic telemetry equipment at Philadel- 

 phia Aquarama, A - in air, B - in water at a range of 20 ft, after ex- 

 treme physical exertion 



put on; in addition, the procedure was too complicated. Consequently, the electrodes were often 

 put on improperly, and signals with considerable extraneous noise were therefore obtained. 

 Studies are being conducted to obtain a special electrode design optimized for use under a wet 

 suit. For example, a thinner electrode that can be held in place by the pressure of the wet suit 

 will be considered. 



Recent studies at the Philadelphia General Hospital indicate that it will be possible to elim- 

 inate the third or ground lead entirely. If further analysis of the two- lead system proves suc- 

 cessful, the time required to put leads on will be reduced by one-third by thisfactoralone. The 

 goal will be to design effective electrodes that can be put on easily in a few minutes. 



2. Simpler and Quicker Mounting to the Scuba-Tanks 



In the equipment delivered to Sealab 11, the transmitter was attached to the scuba tanks by 

 two steel bands which were tightened in place by use of a screwdriver (Figures 89 and 90). It 

 is an easy matter to redesign the mounting in the form of a snap- on type device that will allow 

 attachment and removal of the transmitter in a few seconds without tools. 



