ST-15 PTT Configurations for Cetacean Research

Instrumentation of cetaceans is a complex exercise requiring coordination of numerous facets of telemetry technology. In most instances whales are not physically handled or restrained. If whales can be handled, most researchers use the configurations listed under the section on ST-18, ST-16, and ST-14 PTTs. When researchers are instrumenting free ranging unrestrained animals, they must often be instrumented during brief surfacing intervals using remote deployment techniques that vary widely depending upon species under study and pursuit craft, i.e., native craft, zodiacs, ocean kayaks, small mobile motor boats, and even helicopters. Most researcher who have been successful at instrumenting free ranging whales have developed techniques specific to the species under study, the region of the world where they will be working, the research funds available for the instrumentation effort and other factors that are involved in this complex operation. Most cetacean researchers have developed their own deployment systems for working on specific species. Typically the instrumentation package is integrated into a projectile that must be launched or fired from the delivery device. The delivery device or system can often be a crossbow or modified firearm. These delivery systems are developed by individual researchers and are not supplied to the community through Telonics or any other telemetry manufacturer. Because deployment or delivery systems can vary widely there are few "standard off the shelf" instrumentation packages. To meet the very specific needs of the research community we typically use one of two basic approaches for developing and supplying telemetry equipment for free ranging unrestrained whale work.

Option 1: Telonics supplies the telemetry electronics and the end-user designs and manufactures the housing, and also integrates the subsystem with their delivery system. In this approach the researcher or technician will need to be familiar with radio frequency components, antenna design, packaging technology and shock related issues associated with delivery of the instrument package.

Option 2: Telonics works with the researcher to take our electronics and battery system and integrate them into the researchers housing subsystem. For this approach to work successfully Telonics should be involved as early on as possible with the design of the housing and the delivery system. Telonics helps to advise the housing developer in issues associated with positioning and functional issues associated with the saltwater switch. Additionally, shock related issues must often be addressed. Typically there is a nonrecurring consulting/engineering fee for the initial engineering effort that leads to the development of the housing. An integration fee is then charged for each telemetry system assembled and tested.

A note regarding high pressure deep diving applications associated with deep diving species. For deep diving whales a solidly cast PTT electronics is often required to handle the pressures and prevent crushing at extreme depths. The CAST-7 full internal casting option eliminates all air-pockets from around the electronics and throughout the packaging. This option allows exposure to depths of 500-1000 meters or more. Although the final units are provided with a full internal cast (CAST-7) and all air surrounding the electronics and packaging is eliminated, the cells are nearly solid internally but do contain (CAST-7) and all air surrounding the electronics and packaging is eliminated, the cells are nearly solid internally but do contain some voids and correspondingly they can be crushed at sufficiently high pressures. That being said , the 2/3 A sized cells used in the ST-18 PTTs have been tested by customers for up to 24 hours at 1000 psi (approximately 700 meters) with only minor kinking in the cell case. Another test was performed at about 1500 psi (1000 meters). The pressure created minor kinking in 5 minutes, but moderate cell crushing when allowed to sit for 24 hours at that pressure. The cells still functioned even though physically damaged. We do not have specific information regarding cell's survival possibilities at higher pressures.

ST-15 Electronics Only Configurations

The ST-15 PTT can be procured in an electronics only configuration suitable for incorporation into a user provided housing. The electronics configuration is not provided as a bare board with exposed electronics. When sold to the user for installation by the user the unit is provided in a light weight hermetic brass housing that prevents incidental damage to the electronic components and circuitry during the integration process. However, depending upon the arrangements made the user or Telonics can actually do the integration. This unit is not sold with the CAST-7 option for user installation. The integration process require a significant level of expertise including soldering skills, mechanical assembly skills, and a good understanding of performance of various battery systems under load and temperature conditions appropriate to the configuration. Further, the user must understand the technical aspects associated with the saltwater switch technology and the design of an appropriate antenna system for the configuration. Telonics cannot "tutor" researchers in all these areas of integration and we suggest that professional staff with radio transmitter or satellite expertise be employed to accomplish these tasks. Further, the full responsibility for the design elements and all aspects of testing now fall into the hands of the end user. Telonics responsibility ends in providing a functional PTT electronics meeting the electrical and mechanical specifications set forth in this section. Note: When procuring The ST-15 electronics only configuration a basic set of test procedures can be utilized to evaluate the basic electronics performance. This test procedure is not all inclusive and does not test the Argos uplink specifically. Other tests using the TSURB Uplink Receiver and on the air Argos tests should be developed and incorporated by the end user into their overall test procedures. The ST-15 Test Procedure Manual is available from Telonics.

ST-15 Specifications

Argos Type Certification: MODEL CM 10001-004
Weight: 11 g, Electronics Only (For Reference), 18 g, Installed in hermetic brass housing for user installation.
Size: 2.5 " (L) X 0.67" (D) (Click here to view PDF for full mechanical details)
Frequency: 401.650 MHz (In accordance with Argos Specifications)
Operating Temperature Range: OPTION 004, -40° TO +70°C; OPTION 005, -40° TO +60°C.
Storage Temperature Range: -60° TO +80°C.
Humidity: 90% NON-CONDENSING.
Power Output/Peak Current: 500 mw*/385 ma at 7.3 Vdc, 400 mw*/355 ma at 6.0, Vdc, 200 mw*/315 ma at 4.0 Vdc, (50Ω Load Impedance).
Voltage: +4.0 Vdc to 7.2 Vdc.
Quiescent Current: <45 ua (Operating), <5 ua (Shutdown).
Case Polarity: Negative (-) Ground
RF Output Impedance: 50Ω
ON/OFF Switching: A normally open (N.O.) switch turns the PTT on.

ST15 Configurations with Integrated Battery Systems in Cylindrical Housings

If a researcher wishes to procure the PTT, battery, and housing in an integrated form, several housings have been developed and can be ordered. In most applications where PTT and the battery system can be placed into cylindrical housings, the CAST 7 option is available and the entire internal structure is cast solid. In some instance refurbishment of these units is not possible and in other instances the unit can be refurbished. Please consult the factory on all refurbishment issues prior to ordering any of the following configurations with a solid cast. The housing available represent housings that have been developed for specific customers. Other housing options can be developed for other applications. The development of special housings typically involves nonrecurring engineering fees.

TCU-150

An ST-15 Argos Certified PTT powered by 2ea. 2/3 A-sized batteries. The electronics and power system are housed in a high impact polycarbonate housing (see Fig. 1). The saltwater switch contacts are mounted on either side of the antenna. The unit is able to detect surfacing within 300 millseconds and initiate an Argos transmission. The unit is produced in the fully cast form with the CAST 7 option. This option is designed to withstand pressures of greater than 1000 meters. A stout 1.5 inch section of polycarbonate material is provided at the bottom end of the unit for installation of user provided attachment hardware. The user must also interface and test this unit with their delivery system. The unit is equipped with a TA-5HT Teflon coated whip antenna. Other special antennas can be specified for specific applications.

TCU-150

Housing Dimensions: 6.0" (+ 1.5" interface) length x 1.0" outside diameter. (Click here to view PDF with full mechanical details.)
Weight: approximately 150 grams.

Operational life assuming 50 second repetition period:
20 days with 100% duty cycle and all time spent on surface
79 days with 25% duty cycle (or approximate time spent on surface)
182 days with 10% duty cycle (or approximate time spent on surface)

TCU-245

An ST-15 Argos Certified PTT powered by two PS5875-001 batteries. The electronics and power system are housed in a high impact polycarbonate housing (see Fig. 2). The unit is shorter but larger in diameter than the TCU-150. The saltwater switch contacts are mounted beside the antenna. The unit is able to detect surfacing within 300 milliseconds and initiate an Argos transmission. The unit is produced in the fully cast form with the CAST 7 option. The CAST 7 Option is capable of withstanding dives to over 1000 meters depth. The user must also interface and test this unit with their delivery system. The unit is equipped with a TA-5HT Teflon coated whip antenna. Other special antennas can be specified for specific applications.

TCU-245

Housing dimensions: 4.0" length, 1.378" outside diameter (Click here to view PDF for full mechanical details)
Weight: approximately 110 grams

Operational life assuming 50 second repetition period:
14 days with 100% duty cycle and all time spent on surface
55 days with 25% duty cycle (or approximate time spent on surface)
126 days with 10% duty cycle (or approximate time spent on surface)

Duty-cycling is used to turn the PTT on and off so that the battery capacity is not wasted when the satellite is not in view, or when data are not required. During the "on" times, the repetition rate determines how frequently the PTT actually transmits its 360 millisecond pulse. Repetition rates are assigned by Argos. In most marine applications, a 45 to 50 second repetition rate is most favorable to obtain position at sea.

Estimates of PTT operational life assume a 50-second repetition periods. Of course you are not limited to the above duty-cycles. It is best to review the satellite overpass data for your study area to determine the duty-cycle that will best accommodate your study. If you require satellite overpass predictions, please provide us the latitude, longitude, and elevation of the study area, along with an approximate deployment date.

TCU-150 and TCU-245 Saltwater Switch and Antenna Options

The configurations listed above are typically ordered with a saltwater switch option that assures synchronization of the Argos transmission with surfacing. The switch also suppresses transmissions while the unit is under water, thus saving power and maximizing operational life of the configuration. The power savings associated with the saltwater switch (suppressing transmissions while the animal is under water) is additive to the power savings associated with duty cycling.

Various antenna options are also available to allow the selection of the appropriate antenna material. Any PTT requires an antenna to radiate the signal to the satellite; therefore, appropriate antenna design is critical in successful deployment and function of a PTT subsystem. In many applications, the TA-5HT transmitting antenna is used. This antenna is a multi-stranded, stainless steel cable, approximately one-quarter wavelength (about 7.5 inches) in length (e.g., the Telonics TA-5HT, 0.085 inch diameter antenna).

ST-15 Software Options

Numerous software options are available that allow the researcher to acquire data on such parameters as surface time, dive time, and number of times the animal surfaces. The units also feature a flexible transmission scheduler that allows the researcher to choose specific transmission times to meet research goals.

Software choices for the ST-15 PTT for marine applications include:

Service Commitment

Since 1970, Telonics has built a reputation based on product quality, product support, service, and customer satisfaction. Telonics strives to produce the highest quality products, and to support those products accordingly.

Because of extreme conditions and the unpredictable nature associated with most telemetry applications, problems occasionally arise. Most problems can be resolved quickly. In all cases, we hope to be able to work in partnership with users to resolve problems to the user's satisfaction and to uphold our demonstrated commitment to excellence. If problems should arise, all products must be returned to our factory for failure analysis.

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