Developments in terrestrial and satellite radio systems for biological tracking and location studies

The aim of this paper is to describe some of the developments in radio technology which have been applied to transmitters suitable for terrestrial and satellite tracking studies of animals ranging from arctic polar bears to small birds of prey and fish. The design of radio location and tracking systems depends on available frequencies, transmitter powers and antennas. For terrestrial tracking applications novel circuits used for miniature transmitters are discussed together with the impact of new technologies such as plasma and chemically etched HF quartz crystals. The design of coherent VHF and UHF transmitters in this application depends upon the available DC primary power and the length of time the transmitter is required to operate. Battery technologies are key in terms of their mA/hours, weight and volume and the influence on the circuit design i.e. whether frequency multiplication stages or direct synthesis techniques are employed. The pulsing of coherent miniature transmitters is very relevant and novel designs for pulsed transmitters are illustrated with their attendant characteristics