18
4.3.
VHF Receivers and Antennas
Refer to the user guides that came with your VHF receiver and antenna to
ensure that you understand:
How to optimise sensitivity (gain)
The direction the antenna is polarised; and
The implications of polarisation to tracking
4.4.
Behaviours
Some VHF transmitters are programmed with behaviours. Behaviours can be
used to conserve the battery’s charge, for example, by transmitting a slower
pulse rate (or no pulse) during daylight, e.g., when a nocturnal animal is safe in
its burrow.
Behaviours determine:
When the VHF transmitter broadcasts a particular pulse pattern; and
The rate at which the pulse is broadcast
For example, your VHF transmitter may have been programmed to transmit its
nominal pulse rate for 12 hours a day, five days each week (to conserve battery
charge) and for the remaining time, broadcast nothing.
NOTE: Behaviours count down from the time the VHF transmitter is switched on.
4.5.
Mortality Pulse Rate
Some VHF transmitters are fitted with a motion sensor and are programmed to
broadcast a mortality pulse rate. The VHF transmitter will broadcast the
mortality pulse rate when the host animal remains motionless for a specified
period of time (mortality timeout period). This mortality timeout period is
factory-set and cannot be changed.
