Telonics, Inc. Products - Telonics Argos Transmitter (PTT) Models for Marine Applications

Fig. 1

Fig. 1. Five fully configured models designed specifically for marine applications are shown. Researchers can choose various exit angles for the antenna and the position of the saltwater switch at time of order. Tubing provides strain relief and mechanical protection for the antenna assembly.

Introduction

The latest Telonics Argos Marine Transmitters represent a new generation of Argos PTTs (Platform Transmitter Terminals), or simply Transmitters. The models described below are based on the ST-20 and ST-24 Argos Certified Transmitters. The electronics are installed in a waterproof and pressure-resistant package, including batteries, antenna, and a saltwater switch.

These models' designs include highly efficient transmission circuitry and support for sophisticated uplink duty cycling regimes that function to extend the operational life of the unit. In addition, during active transmission periods or "on periods", a micropower saltwater switch (SWS) saves additional power and further extends the operational life of the unit. The SWS is critical to successful performance of an Argos marine unit. Because radio frequencies are severely attenuated in salt water, any uplink transmissions while underwater are essentially wasted. The SWS functions to suppress transmissions while the unit is submerged thereby saving power. The SWS synchronizes uplink transmissions to resume at the precise time when a marine animal actually breaks the sea surface following a dive. By transmitting immediately upon resurfacing, the unit has the best chance of successfully getting uplink transmissions to available orbiting NOAA satellites. Further, the SWS can be used to determine a haul-out condition and shut down Argos transmissions during extended shore time to save additional energy.

These models were first deployed on marine turtles and marine mammals in spring 2003 and now have demonstrated performance history. These models are small, lightweight, capable of long operational life, and provide highly sophisticated flexible data collection regimes. These models are quickly becoming standards in the marine field.

The models documented below replace models based on the ST-6, ST-10, ST-14, ST-15, ST-18, and ST-19.

To minimize package size, a VHF beacon transmitter is not integrated into the assembly. If required, a VHF unit can be purchased separately. When deploying both an Argos transmitter and a VHF unit, the positioning and mounting should be done in a manner that minimizes interaction of the two antenna assemblies. Please consult with Telonics if there are concerns over this issue.

Key Features

Operational life is extended by a factor of three relative to older transmitter models, due to ultra-low quiescent current and highly efficient radio transmission circuitry.
Real-time clock calendar (RTC) controls all timing functions.
Powerful data collection and transfer capabilities allow the units to acquire, queue, and transmit temperatures and dive information.
User programmability allows researchers to reprogram units in the field and change their role and mission.
- On-board sensors can be activated or deactivated in the field. Data collection regimes and schedules can be altered as required. Sensor data can be enhanced or deleted from Argos uplink transmissions.
- Transmission schedules can be modified.
- Argos ID codes can be changed.
- Argos uplink transmission power levels can be modified to extend operational life or increase the probability of signal reception at the satellite.
- Argos uplink frequencies can be changed to frequencies in low noise channels to increase the chances of a successful uplink.
Units can be refurbished to their original condition at the factory.
Shutdown with a small magnet allows users to turn each of these configurations "on" or "off". When turned "off", ST-20 based units consume less than 8 μA, and ST-24 based units consume less than 4 μA. Given these low current levels, users can store their units for extended periods with minimal impact on operational life.

Configuration Tolerance to High Pressures

The models described below are internally solidly cast with a polymer capable of withstanding the extremely high pressures experienced during deep ocean dives. Some researchers have tested units in hyperbaric chambers to failure. In general, the battery system determines how much pressure the unit can withstand. Most fully cast configurations can withstand pressures exceeding 1500 psi if the exposure is short term. Other researchers have tested units in the field and returned them to Telonics for refurbishment. We have found some damage to the battery cases during short exposures (<5 minutes) to depths of 1000 to 1500 psi. Cells remain operational but can show "creases" or "kinks" in the cell case. Long-term exposure to such pressures (>24 hours) can crush the cell cases, however it is interesting to note that the cells continue to function and deliver current following the damage. In general, this housing and packaging technology has been successful in long term deployments on known deep-diving species.

Models

How to use this table: The information contained in the following table is provided in a manner to allow comparison of models. To sort by model attributes i.e. weight, CLICK ON THE COLUMN HEADING. To obtain more specific information for a model, CLICK ON THE MODEL NUMBER.

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Model	Size	Unit Weight (g)	Pressure Sensor	Low power (mW)	Low power life (hours)¹	Low power temp (°C)	High power (mW)	High power life (hours)¹	High power temp (°C)
A-118	1.1 x 2.6 x 0.75 in 2.79 x 6.6 x 1.9 cm	49	No	160 (Typ)	657	+5 to +60	250 (Typ)	517	+10 to +60
A-119	1.3 x 2.6 x 1.2 in 3.2 x 6.6 x 3.0 cm	90	No	160 (Typ)	2748	-25 to +60	250 (Typ)	2140	-20 to +60
A-210	4.0 x 1.75 x 0.85 in 10.2 x 4.4 x 2.2 cm	190	No	500 (Typ)	494	-20 to +60	N/A	N/A	N/A
A-225	4.0 x 1.75 x 0.98 in 10.2 x 4.4 x 2.5 cm	245	Yes	500 (Typ)	494	-20 to +60	N/A	N/A	N/A
A-410	5.1 x 1.75 x 0.85 in 12.95 x 4.4 x 2.2 cm	215	No	500 (Typ)	1071	-20 to +60	N/A	N/A	N/A
A-425	5.1 x 1.75 x 0.98 in 12.95 x 4.4 x 2.5 cm	270	Yes	500 (Typ)	1071	-20 to +60	N/A	N/A	N/A
A-1010	2.4 x 4.85 x 1.1 in 6.0 x 12.3 x 2.8 cm	276	No	500 (Typ)	1874	-30 to +60	1000 (Typ)	739	-30 to +60
A-1025	2.4 x 4.85 x 1.23 in 6.0 x 12.3 x 3.1 cm	331	Yes	500 (Typ)	1874	-30 to +60	1000 (Typ)	739	-30 to +60
A-2010	5.5 x 3.0 x 1.5 in 13.97 x 7.6 x 3.8 cm	540	No	500 (Typ)	5421	-30 to +60	1000 (Typ)	2370	-30 to +60
A-2025	5.5 x 3.0 x 1.6 in 13.97 x 7.6 x 4.1 cm	595	Yes	500 (Typ)	5421	-30 to +60	1000 (Typ)	2370	-30 to +60

1. Operational life expectancy is based on a continuous series of transmissions of a 4-byte Argos message at a 45-second repetition rate at 25°C.

Coming online soon Generation 4 GPS Systems with Quick Fix Psuedoranging

Legacy Products

Telonics still supports and refurbishes these products, but no longer sells them new:

ST-18 and ST-14 PTTs for Mammals and Turtles
ST-15 PTT for Cetacean Research
ST-15 PTT for Walrus

Technical Notes

Argos System Background

Argos Marine Transmitters