Tag Design 



Our tag housing and attachment design team consisted of Bruce Mate and 

 Roderick Mesecar. Tag software was developed by Toby Martin and Walt Dillon. The 

 MMS-sponsored workshop on cetacean radio tagging (Montgomery, 1987) was reviewed. 

 We examined each of the previously successful VHF and HF conventional radio tag 

 designs created by Goodyear (1981), Mate, et al. (1983) and Watkins, et al. (1981) in 

 addition to the OSU satellite-monitored Argos work on pilot whales (Mate, 1989), 

 manatees (Mate, et al., 1988) and humpback whales (Mate, et al., 1983). Individual tags 

 and attachments were discussed with Tony Martin (Sea Mammal Research Unit, 

 Cambridge, England), Kathy Frost and Lloyd Lowry (Alaska Department of Fish & 

 Game), Joseph Geraci and Jeff Goodyear (University of Guelph), June Wilson-Hench 

 and Larry Hench (University of Florida), Robert Hofman (Marine Mammal Commission) 

 and Scott Kraus (New England Aquarium). From this research, it was determined that 

 the design priorities were: 1) low profile to reduce drag; 2) a flexible base to conform to 

 the curvature of the whale; 3) at least two attachments; 4) preferable use of bio- 

 compatible materials; 5) good antenna orientation; and 6) ability to withstand pressure of 

 750 psi (500 m depth). 



1989 



After reviewing the certified Argos transmitters with their manufacturers, we chose 

 the Telonics ST-3 as the most compact, durable and energy-efficient unit for the 1989 

 field trials. This unit also had an asynchronous serial port (a user interface), which 

 allowed us to incorporate our own sensors and controller. We developed a 

 microprocessor controller to provide onboard data management, collect temperature and 

 pressure data from special sensors, interrogate a saltwater switch, coordinate 

 transmissions with the satellite, and calculate a "cyclic redundancy check" (CRC) code to 

 detect errors. 



Housing 



We decided that protection from pressure could most easily be accomplished by 

 building the transmitter in a cylinder. The ST-3 transmitter measured 13.75 cm long by 7 

 cm wide by 1.5 cm high. These dimensions determined the 7 cm minimum diameter and 

 15 cm length of the cylinder housing. 0-ring sealed endcaps housed the pressure and 

 temperature sensors at one end, and the saltwater switch and a 16.5 cm flexible whip 

 antenna at the other end. The remaining space was sufficient to accommodate six Altus 

 C-cell organic lithium batteries and the OSU-designed microprocessor board. 



Software 



In 1989, we attempted to synchronize the PTT transmission cycle with satellite 

 movements in order to use the PTT battery power as efficiently as possible. The orbital 

 elements of the NOAA 10 and NOAA 11 satellites were determined using the Telonics 



