ATS has been supplying complete radio tracking systems to researcher's worldwide for over twenty years. If your research requires even the simplest of systems, depend on us to provide you with the expertise needed to design, deploy, and maintain it. ATS has helped thousands of biologists, conservationists, and ecologists to successfully carry out a wide range of important research on most every group of species, whether mammal tracking, marine mammal tracking, avian tracking, fish tracking, or reptile tracking. In order to help researchers decide what kind of system will work best for them, they should understand the basics.

All radio tracking systems consist of three primary components. They are:

  1) The transmitter(s), affixed to the research species

•   2) The radio receiver and/or datalogger
•   3) The antenna system and associated cabling

In examining the three components in more detail, this discussion will limit itself to manual radio tracking systems. However, the fundamentals of radio telemetry apply to other systems, such as fixed station tracking or aerial tracking. All three of the system's components must work together in order to successfully conduct radio tracking. Keep this in mind if the need to troubleshoot arises.

ATS manufactures a wide variety of transmitters that operate in the VHF frequency range. There are four primary components to radio transmitters used in fisheries and wildlife research. 1) a power source, normally a battery 2) the electronics package, consisting of the circuit board and a crystal oscillator 3) the antenna, and 4) an attachment method. Detailed information about ATS transmitters, their specifications, and considerations for selecting them can be found at "Transmitter Specifications Explained".

The important aspects of the transmitter to consider are its total weight and its operating life. These two variables are mainly a function of the battery type and its size. The larger the battery, the longer the life of the transmitter, and of course, the transmitter will be heavier. The size of the battery will in general, not have any affect on the range of the transmitter, only its overall life. However, the antenna will, and depending on the frequency used, each antenna is cut ideally to a specific length which corresponds to the wavelength of the frequency. This optimizes the antenna's range characteristics. The crystal oscillator generates the signal at whatever frequency it is tuned to. ATS stocks a complete range of various frequencies used by state, federal and institutional tracking organizations.

Attachment methods vary widely. They may be collars, necklaces, or any number of different types, depending on the species being studied. In the Transmitter Product section of this site, you will see the various methods commonly used for your study species. An ATS Sales Consultant, who is also a Biologist, can help you determine the most efficacious attachment method for your work.

It is important to remember that each transmitter is, in effect, custom built to your specifications. The specific frequency requested, attachment method, and the battery life the study requires, are all variables which affect the design and assembly of transmitters. Keep this in mind when ordering transmitters. ATS Customer Service always sends an "Order Confirmation" via e-mail to our customers prior to starting production. In order to insure order accuracy, please check that the specifications given for your order are exactly as you and your Consultant had discussed.

A successful animal tracker will need a quality radio receiver, like ATS's R4500 Receiver/Datalogger, in order to pick up the signal generated by the transmitter. An antenna is cabled to the receiver. Remember that the frequency range of the receiver must match up with the frequencies the transmitters are using. ATS receivers are known for their high quality, field versatility, and most importantly, high sensitivity. ATS' latest receiver, the R4500, utilizes digital signal processing techniques, or DSP. Special filters are used to digitally sample the input audio signal and digitize it, allowing use of a high-order algorithm to process the data. This helps filter out spurious signals in very noisy environments, such as in urban areas (often, even in remote, uninhabited areas).

 

There are two types of receivers available: scanning and manually tuned. For studies on a small number of individuals, manual radio tracking on the ground using a basic receiver might only require either ATS' Model FM-16 or FM-100 Receiver . With this type of receiver, the tracker manually switches through the channels (frequencies) he needs to monitor individuals (transmitters) on. The FM-16 can be tuned to sixteen different channels (frequencies), the FM-100, to 100 channels.

For larger projects, a scanning receiver such as ATS' R4500, which can scan up to 400 frequencies, is ideal. This type of receiver also operates as a datalogger, allowing the researcher to easily save tracking data while in the field. All ATS receivers come complete with a padded carrying case (except R4500) and shoulder strap, battery charger (except Model FM-100), and operating manual.

In a simple homing system, only a single antenna is used. In more complex radio tracking systems, multiple antennas may be used (see "Fixed Unattended" and "Aerial Tracking"). The antenna is connected to a radio receiver using coaxial cable, usually type RG-58. To maximize the gain of the antenna and minimize signal loss, the shortest possible length of cable should be used.

ATS recommends carrying spare antenna cables while in the field. One of the weakest points in the system is the cable and its connectors, since they receive continual stress when radio tracking animals in heavy brush and cover. Many times the connector and cable crimp point will be compromised, causing the system to fail.

Radio tracking has been used in animal behavior and biological research since the early 1960's. Although more complex triangulation methods may be used, homing is the basic skill used in tracking terrestrial animals. The objective is to visually locate the animal if possible, and record habitat and other biological data.

Having connected and powered up your equipment, that is, your receiver, antenna and cable, and headphones, you'll first need to tune the receiver to the correct frequency for the transmitter you want to track. With the receiver's volume at a comfortable level, the gain control (which controls the sensitivity of the receiver) should be set at the "full" gain position. As progress toward the animal is made, the gain should be reduced to the lowest level that will still allow the researcher to hear the signal; adjustments to the receiver's gain control can be made as required. Avoid changing the volume level if possible. Now, assuming ATS' hand-held Folding 3 Element Yagi Antenna is being used, it should be held in the vertical plane, and then a slow sweeping motion of the antenna should be made up to 360 degrees. One must listen carefully to the receivers output using the its speaker, or, much better, a set of headphones. Once the tracker is within range of the individual, he'll hear the transmitter beeping.

The most important sensing device used by the tracker are his aural senses. The ability to sense changes in signal amplitude, or volume, is one that animal trackers will need to refine. If you're just starting out, you might try closing your eyes as you sweep the yagi antenna around in a circle. The objective is to determine which direction the animal is located; as the volume of the beeping increases, the distance from the animal is decreasing. You'll continue to move closer to the animal while continuing to slowly sweep the antenna in smaller and smaller "slices" of a circle. As the signal becomes stronger and directionality more difficult to discern, the receiver gain may be reduced in order to decrease its sensitivity. If one needs very low sensitivity, the antenna may be disconnected from the receiver entirely, the gain control increased, and then one must move back and forth in search of the transmitter. In short order the researcher will be within visual range of his or her target.

For more specifics relating to radio tracking, a wealth of information is available. This site has available a list of further reading materials if you're interested. You can also contact one of the expert trackers at ATS for more help.

The rigors of tracking suggest that your equipment be fully prepared for use. ATS Product Support Services can help. For a nominal charge, our technicians will give your receiver(s) a complete bench-check and operational test prior to the tracking season, which will help insure field work will be uninterrupted by equipment problems. There are few more steps to can take in order to help time in the field go smoothly. First, don't skimp on spares; always carry a spare receiver, antenna and cable if possible. At a minimum, a spare coaxial antenna cable and field tool set should be kept handy. Make sure receiver batteries are fully charged before leaving for the field. Lastly, check and test the equipment as a complete system, using a reference transmitter to verify all of the components are operating correctly.

Should you encounter equipment problems and would like assistance, please contact ATS. We can help you troubleshoot your system over the phone.