ke4nt1
Group: Members
Posts: 2329
Joined: Oct. 2003 |
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Posted: Nov. 02 2004,17:32 |
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Here's a brief...
I use a Terminal Node Controller , or "TNC" for short.
It's basically a "radio modem" ,
and looks very similar to a typical external modem.
Here are two different models I have.
The smaller one gets its power directly from the com port.
This connects up to a serial port on the back of the computer.
Another cable connects the TNC to a transceiver, in this case,
a Radio Shack HTX-202 2-Meter ( 144 MHz - 148MHz ) radio.
It's set to 144.390 MHz , the National APRS frequency.
It is connected to the microphone and earphone jacks.
The FAT cable you see exiting the top of the radio runs out
to a 13 element antenna, designed for the 144-148 / 2 Meter Band.
It spins around with a "TV" rotator, so I can track the passing
of the ISS from horizon to horizon. I monitor the path of the
ISS with the predict / GSat server and GUI.
Xastir 1.4.0 communicates with the TNC, just like and old style
X-Modem or Procomm program would with a typical modem.
The TNC creates the "packets" of data that are sent in an
audio stream ( remember how 300 baud sounded? ) to the
transceiver, and broadcasted out to the airwaves.
Next post, I'll walk thru the xastir setup..
73
ke4nt
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