The ST-21 replaces the ST-20. The ST-21 is functionally equivalent, but contains Telonics new transmitter module.
Campbell Scientific's ST-21 is a Service Argos-certified platform transmitter terminal (PTT). The ST-21 transfers data from the datalogger site to the Argos Data Collection and Location System via NOAA polar orbiting satellites. This Argos transmitter is well suited for remote meteorological and environmental data collection applications, including mobile and high-latitude installations. The ST-21 Argos transmitter is compatible with Campbell Scientific's CR800, CR850, CR1000, and CR3000 dataloggers.
Campbell Scientific combines a Telonics ST-21 transmitter module with a voltage regulator and our SDC communication interface, and puts them in a rugged case for use in remote, hostile environments.

Features

Provides uplink capability for up to eight unique ID codes, frequencies, and repetition periods
Supports up to seven independent Argos data buffers that can be populated in real-time
Transmits variable-length Argos messages with either 20- or 28-bit ID codes
Allows researchers to forego a rigorous certification process
Includes an autorepeat feature that allows the ST-20 to repeat data without host intervention
Provides a failsafe feature that alerts users upon communication link or host failure
Incorporates a Campbell Scientific CS I/O SDC communication interface for connecting to our dataloggers
Allows the ID and repetition rates to be set in real-time or by Campbell Scientific

Specifications

Supply Voltage: 12 V, nominal
Output Impedance: 50 ohms
High Power Level: 800 mW typical; 27 to 31 dbm
Argos Transmission Frequency: 401.618 to 401.680 MHz
Modulation (BPSK): -1.1 to +1.1 ±0.1 radians
Current Drain at 12 Vdc
Quiescent: 1.12 mA
Transmitting: 375 mA
Spurious Emissions: -45 dB

Producing Area:USA