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


Model Weight Standard Life Lifespan range Dimensions: L x Diameter (mm)
MI-2 27g 24 months 12-30 months 42 x 18
MI-2 45g 36 months 24-60 months 48 x 20

Frequency Range: 138 to 235 MHz.

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

Pulse Width (standard): 24 milliseconds (ms). Available from 22-30ms.

Pulse Rate (standard): 40 pulses per minute (ppm). Available from 20-120ppm.

Power Output: Set to use available battery power over the required transmitter life.

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. The antenna can also be fully enclosed within the collar for maximum protection.

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


Mortality (suffix “M”): The available delays are 4 or 12 hours. 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 ppm to ~75 ppm. 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.

Activity (suffix “A”): Every motion event exceeding a preset range of angles generates one extra pulse between the normal pulses. This activity pulse is distinctively shorter (~12 ms) than the normal pulses. This option adds ~0.5g to the finished weight of each transmitter.

Temperature (suffix “T”): An increase or decrease in temperature results in a corresponding increase or decrease in pulse rate. At the standard settings, the pulse rate changes from ~15 ppm at 0°C to ~50 ppm at 40°C. Each transmitter is supplied with a plotted calibration curve. This option adds ~0.05g to the finished weight of each transmitter.



Pine Marten release. (Note: Video is in Dutch).