How-tOS

• For birds, transmitter weight should not exceed approximately 3% of the body weight.
• Fish, weight should not exceed 2 - 3%.
• Reptiles and amphibians, 3 - 5%.

We publish the average weight for each transmitter model. There will always be a degree of variablitiy in the final transmitter weight; we try to keep it to 15% or less of spec.

Please note that some model series' weights do not include attachment material weights. Also, requested "deviations" to the production design can significantly change the final weight.

• The trade-off is between transmitter weight and life; a larger, heavier battery will last longer than a smaller, lighter one.
• Most transmitters use lithium batteries and have a shelf life of several years.
• Smaller transmitters using tiny button-sized silver oxide batteries have a very limited shelf life.

• Smallest transmitters use simple circuits and cannot be programmed (designated as “astable circuit” transmitters)
• Larger transmitters can be programmed (designated as micro-processor controlled) and can include features like mortality, duty cycle, etc.
• Some models offer an increased range option (a two stage vs. a three stage circuit), indicated with a “B” suffix.
• Higher pulse rates and widths reduce transmitter life, lower increase life.
• The faster the pulse rate, the easier to track and home-in on the animal (the "beep- beep" tone).

• Each finished transmitter is labeled to identify its unique frequency.
• We space the transmitter frequencies 10 to 20 kilohertz (kHz) apart. If there are other researchers using nearby frequencies in your planned study area, tell us and we can avoid them.
• Smaller transmitters using silver oxide batteries have limited storage life and should be deployed within 1-3 months of delivery. Otherwise transmitter shelf life is about 5 years.
• All transmitters are turned on and off by removing or replacing a small magnet taped to the unit.