Campbell Scientific’s ST-21 is a Service Argos-certified Platform Transmitter Terminal (PTT ) that transfers data from the data logger site to the Argos Data Collection and Location System via NOAA polar orbiting satellites. This transmitter is well suited for remote meteorological and environmental data collection applications, including mobile and high-latitude installations. The ST-21 is compatible with our newer data loggers.Read More
While Campbell Scientific's ST-21 Argos PTT is based on Telonics' ST-21, they are not equivalent; our ST-21 includes a case, voltage regulator, and our SDC communication interface.
Please note that when ordering the transmitter, the customer needs to provide Campbell Scientific with the number of buffers, repetition rate, decimal ID, Dex ID, frequency, and fail safe information.
To use the Argos system, you must receive formal permission from Service Argos and pay a fee. The data must be used for environmental purposes. Examples include meteorological/hydrological stations, ship tracking, volcano monitoring, and seismic data.
Choose one of the following methods:
|Operating Temperature Range||-30° to +70°C|
|Supply Voltage||12 V (nominal)|
|Output Impedance||50 Ω|
|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|
|Spurious Emissions||-45 dB|
|Transmission Distance or Area||Worldwide|
|Service Requirements||Must receive formal permission from Service Argos and pay a fee. Must use data for environmental purposes.|
|Dimensions||19.05 x 3.18 x 5.72 cm (7.5 x 1.25 x 2.25 in.)|
|Weight||224 g (7.9 oz)|
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
Our data loggers can format the data as bits per data point, allowing the user to select the resolution used for each data point.
The ST-21 requires a desiccated, non-condensing environment; a Campbell Scientific enclosure is recommended. Grommets and screws are provided to attach the ST-21's flanges to the backplate of our enclosures.
To subscribe to Argos, the following steps must be completed:
Number of FAQs related to ST-21: 5
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The ST-21 is not used via wire. The ST-21 is only used for one-way data transmission via radio frequency to polar-orbiting spacecraft. Limited data throughput with very low power requirements works best at high latitudes.
No. The ST-21 is designed for one-way communication only.
Data throughput is dependent on latitude. The spacecraft are polar orbiting, which creates more frequent satellite passes at higher latitudes. Each satellite pass can provide 15 to 90 data points, depending on cost.
Email delivery or web-based access.