STUDY OF FREE-RANGING SHARKS 473 



Table 10. Signal -reception ranges 

 over water for a 140-MHz trans- 

 mitter of 1-mW power with a 50- 

 cm (quarterwave) vertical whip 

 antenna. Unit transmitting from 

 the surface of the ocean (sea state 

 0).* 



*From Schevill and Watkins (1966), 

 cited in Mackay (1970). 



Table 11. Typical ranges over land for 

 151-MHz transmitters of about 1 mW 

 power with 30-cm vertical whip anten- 



*Data from AVM Instrument Co. 



