SAT SCD/ARGOS
8
The shut down timer will turn the PTT off after the shut down time has expired.
The PTT will not turn back on. Set the shut down timer to zero for extended
operation.
Save the configuration file to a new name. From the PTTComm menu bar,
select File, Save As and save the file to a new name. You may need the
original configuration file at a later date.
3.2.1 Loading the Configuration to the PTT
Assemble the hardware. You need the SAT SCD/ARGOS PTT, the SC532A
with power supply, and two serial cables (SC12). Before you apply power, you
should have a dummy load or antenna connected to the RF output of the SAT
SCD/ARGOS. Do not apply power to the SAT SCD/ARGOS yet. Make the
following connections:
1) PTT to SC532A using the SC12 ribbon cable.
2) SC532A to the PC using an RS232 cable.
3) Antenna or dummy load to the PTT RF output.
4) Connect AC transformer/12 volt DC supply to power source, but don’t
connect to the SC532A.
After power is applied to the PTT, it will start to transmit. Don’t let the PTT
transmit until you have the configuration loaded. Many times a transmission
from inside a building will be picked up by a satellite. To avoid unwanted
transmissions, do not apply power to the PTT before the configuration program
(Pttcomm.exe) is ready.
On the PC, load Pttcomm.exe. Click “File/preferences”. Set the correct
communications port. Also, set the baud rate to 9600. Everything else should
be left to the default values of: UI Exit string = QQQQQQG, Platform =
WildCAT, Prompt Wait (In Seconds) = 70, Verify data as it is Written and
Simple Mode not checked.
Click on file and open the configuration file “SCD_Argos.cfg”, if it is not
already open.
Click on the start button. Apply power to the SC532A; this will power the
transmitter. When the PTT is first powered, it sends a start up message out the
serial port. When Pttcomm.exe receives a startup message, the PTT is put in
configuration mode. Pttcomm.exe will give a message when the PTT and the
computer have established communications. Click on the “Cfg” button to send
the configuration file. In a moment the software will acknowledge the file was
sent. Wait at least ten seconds before you close Pttcomm.exe or power down
the PTT.
4. Satellite Orbit Patterns
At least two POES satellites carry the Argos transceivers and are operational at
any given time. The orbits carry the satellites over the North and South poles
of the earth in a sun synchronous pattern. Orbit period is close to 102 minutes.
The satellite footprint is about 5000 km in diameter. At latitudes greater than
75 degrees, each satellite provides coverage each pass. Each satellite passes
