For certain species that may not tolerate a backpack attachment, particularly aquatic diving birds, we offer two sizes of Implantable PTTs. These specialized PTTs are optimized for operation at body temperature, are
hermetically sealed in a biologically inert material, and can also be made extra pressure resistant for deep-diving species.
|Estimated Transmission Lifetime**
Argos Doppler Locations
Implantable PTTs transmit messages to the Argos satellite constellation. As
a satellite passes overhead and receives those messages, a PTT's
location is estimated using the perceived Doppler shift in signal
frequency of successive transmissions. Triangulating PTTs' positions in
this manner yields locations which are then categorized into "location classes" (LC) based upon their estimated accuracy. Over two-thirds of Argos locations provided by MTI PTTs are in the top three location classes:***
LC3: <250 m radius
LC2: <500 m radius
LC1: <1500 m radius
Please note that Implantable PTTs are not equipped with GPS.
Programmable Duty Cycles
PTTs are programmed with a user-defined duty cycle that dictates when the device will turn ON to transmit and OFF to conserve power. The customizability of these transmission intervals allows PTTs to best accommodate the activity of the species being studied and the project objectives, as well as to budget the battery life of the PTT over the study period, thus extending the usable lifetime of the transmitter.
Ground Track (GT™) Option
PTTs can be programmed with GT™. This feature enables a PTT to also function as a conventional radio transmitter, emitting a UHF frequency at prespecified times that can be heard via a Yagi antenna and receiver. Seasonal GT™ is helpful for locating birds in real time and pinpointing injured study subjects. Mortality GT™ for Implantable PTTs is temperature-sensitive, meaning a PTT will emit UHF signals and switch to continuous Argos
transmission if its temperature drops below body temperature, thus allowing for the swift location of
deceased birds. Please note that the additional power required for GT™ will reduce the operational lifetime of a PTT.
* While conventional thinking suggests choosing a transmitter weighing <3% of a bird's weight, we are aware that birds routinely carry weights greater, and sometimes less, than 3% of their body weight. Because each species is different, it is crucial that you review the literature on your study species and use proper discretion to determine the appropriate transmitter model for your project.
** Estimated transmission lifetimes based on a 6 hours ON / 72 hours OFF duty cycle.
*** Based on 2016 internal test data.