Holohil Systems Ltd. MI-2

These transmitters are mounted in adjustable collars sized to fit animals from rabbits to lynx.

Frequency Range: 138 to 235 MHz.

Transmitter: Crystal-controlled two stage design, pulsed by a CMOS multivibrator.

Pulse Width & Rate: 25 to 30 ms, nominal 0.7 p/s (42 p/m).

Housing: Hermetically sealed cylindrical brass case covered with heavy gauge heat shrinkable tubing which holds the transmitter to the collar.

Attachment: Transmitter is attached to a brown neoprene-impregnated polyester collar. The width and thickness of the collar are selected to be appropriate for the study animal. Available collars are from 9 to 14mm wide and 1.5 to 3mm thick. The collar is fastened with a self-locking nut and captive stud.

Antenna: Stranded stainless steel cable covered with a black nylon coating. Additional layers of shrinkable tubing reinforce the antenna at its base. The antenna protrudes from the center of the collar at the back of the neck.

Activation: Removing an external magnet starts the transmitter. Replacing it stops the transmitter.

Mortality (suffix "M"): The available delays are 4 or 12 hours. Note: the 4 hour delay is only available in the 45g size. The 4 hour delay circuit indicates its activation by a double pulse. The 12 hour delay circuit indicates its activation by increasing the pulse rate from a nominal ~42 p/m to ~75 p/m. After the mortality mode has been triggered, any motion resets the transmitter to the normal pulse rate. This option adds ~0.5g to the finished weight of each transmitter.

Reverse Mortality: The pulse rate will decrease after a predetermined time delay from the last movement. The delay can be preset for 12 hours.

MI-2T transmitter attached to a Japanese Macaque (Macaca fuscata).
Photo: Goro Hanya (2003)

MI-2 transmitter attached to a pine marten (Martes americana).
Photo: Philip A. Wiebe (2002)

MI-2 transmitter attached to a fisher (Martes pennanti).
Photo: Michael K. Schwartz (2001)