The Thelma Biotel transmitters are energy efficient and versatile platforms developed for a wide range of studies on aquatic species and submerged equipment. The various transmitters are produced in five main transmitter diameter sizes: 6.3 mm, 7.3 mm, 9 mm, 12.7 mm, and 16 mm, referred to as size 6, 7, 9, 13 and 16. Transmitter lengths depend on the possible addition of sensors, output power and the desired active lifetime.
In addition to the range of standardized, off-the shelf products, the transmitters are highly customizable in both hardware and software. The sensors available are depth, temperature, acceleration (activity), inclination (tilt angle), mortality, conductivity in fresh water and salinity in salt or brackish water. All sensor combinations are available down to the smallest size, except for the conductivity and salinity products which have a minimum size of 9. The transmitters can be programmed to utilize any carrying frequency between 63-77 kHz, and at any transmitting interval. For fish studies and equipment compatibility, 69 kHz is most commonly used.
Our acoustic transmitters are mainly used for tracking wild fish movement and behavior. Aquacultural research and management are also applications where our tags help make available data which is otherwise impossible to obtain, monitoring welfare and behavioral responses of cultured fish by physiological measurements on individuals. Our transmitters also support measurements directly on submerged moving structures or other physical measurements where wireless data access is important.
Thelma Biotel’s array of standard products encompasses a broad range of acoustic transmitters:
- Standard ID transmitters
- Acoustic sensor transmitters
- System tags
- Frequency modulated, continuous pinging sensor transmitter
The effective transmitting range is dependent on the acoustic conditions on the site and this will differ with noise levels caused by wind and rain, water stratification and such. Our tags also put out different signal strength due to the type of battery and the transducer size. Generally, the larger tags will be able to transmit up to about 1000 m, while the smaller size tags might be limited to 500 m. The actual range of the tags can be shorter or longer than the above stated figures. As it will differ greatly with conditions out of our control, we don’t indicate a set range for each tag but list the tag’s measured transmitting power for you to compare. The range will be different from site to site and under different conditions, that is why we urge our users to run a range test to obtain at least a rough mapping of the site and to be able to reposition receivers if needed.
Please contact us if you need help choosing the correct transmitter for you use or have questions regarding tailor-made solutions and special adaptations.