This series of small transmitters is designed for glue-on application to bats, birds, herptiles and fish. Several harness and tail-mount configurations are available. The applications are limited only by the researchers’ ingenuity.


Model Weight Standard Life Lifespan range Dimensions: LxWxH (mm)
BD-2X 0.31g 12 days 8-15 days 11 x 5 x 2.8
BD-2X 0.35g 21 days 13-22 days 11 x 5 x 2.8
BD-2X 0.45g 28 days 16-32 days 12 x 6 x 2.8

Please note: We do not recommend storage for more than 2 weeks prior to use.

Frequency Range: 148, 149, 150, 151, 164, 165, 172, 173, 218, 219 & 220 MHz only.

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

Pulse Width (standard): 20 milliseconds.

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: The transmitter and battery are encapsulated in an inert waterproof epoxy. Battery placement determines shape. Several mounting options are available. Although the unit is usually glued to the animal (click here for gluing instructions), one or two tubes can be attached for the passage of sutures or harness material (click here for harnessing instructions). Tubes will increase the total weight by 0.05 to 0.1 g. The unit can be attached to a bird leg-band (supplied by researcher). Extra potting is required for implanted transmitters, for use in high ionic environments (e.g. alkaline, saline), for extra waterproofing, or for abrasion resistance where needed. This will add ~0.1 g. See diagrams

Antenna: A stranded stainless steel wire covered with a black or brown nylon coating, or a 0.007″ stainless steel wire. Shrinkable tubing can be added to reinforce the base of the antenna. Helical antennas can be added to allow for implantation (see photos).

Activation: Removing an external magnet starts the transmitter. Replacing the magnet stops the 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 ~25 ppm at 0°C to ~40 ppm at 40°C. Each transmitter is supplied with a plotted calibration curve. This option adds ~0.05g to the finished weight of the transmitter.

Position (suffix “P”): The pulse rate switches from ~24 ppm in a vertical position to ~50 ppm in a horizontal position. This option adds ~0.5g to the finished weight of the transmitter.


Frogs Wearing Mini Radio Transmitters Released Into The Wild