Sutron Corporation Satlink Operations & Maintenance Manual, Rev 8.04.2 11/3/2016 pg. 122
The antenna-aiming feature can aid in correct station setup. It will show the current signal
strength. Signal strength ranges from 0 (no signal) to 5 (excellent signal).
A signal strength of 4 or higher indicates a strong signal.
Satlink needs to consistently report a strong signal for 10 to 20 minutes to indicate good
antenna placement.
If signal strength is varying, the antenna's view of the sky is obstructed.
In theory, any signal strength above 0 means that a transmission can be made.
However, to ensure reliable and consistent data transmissions, reposition the antenna
to get better signal.
A signal strength of 0 indicates that there is no signal at all; Satlink will not be able to
make any Iridium transmissions.
When installing the station, make sure Satlink consistently reports a signal
strength of 4 or higher for at least 10 minutes.
12.1.2.
Short Burst Data
Satlink uses the Iridium Short Burst Data (SBD) capability to send transmissions and receive
messages.
Satlink uses messages to communicate via Iridium. Messages may be sent to Satlink via Iridium,
and Satlink may send messages in return.
Each message may contain up to 340 bytes.
12.1.3.
Transmission Data Content
Each measurement is independently setup with the data content for each transmission. Please
see section Transmission Data Content Settings for details.
A single message can only hold a limited amount of data. If there is more data than can fit,
multiple transmissions will have to be sent. In order to receive the freshest data, the
transmission interval should be set such that only one message is sent at one time. Given the
choice of getting one transmission every 15 minutes or getting two back-to-back transmissions
every 30 minutes, opt for the 15 minute data. The price is the same, but the data is refreshed
more frequently.
Satlink will send up to five separate SBD messages for each transmission, providing a maximum
capacity of 1655 bytes worth of data. If that is not enough data, increase the transmission
interval or setup two different Iridium transmissions.
12.1.3.1.
Iridium Setup
section for details on setting up Iridium.
12.1.3.2.
Iridium Message Checking
When an Iridium Scheduled transmission
is made, Satlink is notified of any incoming messages.
Checking for messages in this fashion does not incur any additional data usage costs.