SCS Tracker Installationsanleitung Seite 26

3. Installation
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Next the Wizzard wants to install the driver for the device "USB Serial Port". Same as
before you select the option "Install the software automatically" and click on "Next".
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After successful installation you click on "Finish".
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With this the driver for the SCS Tracker / DSP TNC is installed.
The installed driver creates a virtual COM port which is used by the applications similar to a
normal (hardware) COM port.
To find out which number the virtual COM port has beed assigned to, you have to look into the
Device Manager of your computer!
Select: Start → Control Panel → System → Hardware → Device Manager. Now click on the
small "plus"-sign left besides the table entry "Ports (COM & LPT)" to see all connections of
your PC. Look for the entry "USB Serial Port" where right besides the COM number is shown.
Enter this COM number into all programs you want to use with the SCS Tracker / DSP TNC.
3.3 Connections to the transceiver
Due to the variety of possible transceiver types which can be used with the SCS Tracker / DSP
TNC, it is somewhat more difficult to find out the correct connection. For many common
transceivers complete manufactured cables are available as accessory (chapter 5 on page 28).
To use this cables, also an adapter from 6 pin mini-DIN to 8 pin DIN socket is required (SCS
part number 8180). Behind this adapter all "PTC"-modem cables can be used to connect
special transceivers. For all the others radios the attached mini-DIN-6 pigtail cable must be
used and completed by the user. Your dealer will help to find the proper connection scheme.
Robust HF-Packet (RPR) uses differential phase-modulation (DPSK), which leads to a small
and efficient spectrum. To maintain the advantages on the HF-frequencies, a proper adjustment
of the transceiver's settings and modulation levels is essential. Over-modulating the transceiver
would lead to unwanted broadening of the spectrum. Refer to chapter 3.3.4 on page 24 for how
to set the modulation levels properly. Modulation level is also critial for the common direct-
FSK (G3RUH) modulation used for 9600 and 19200 baud VHF/UHF Packet-Radio.
Robust HF-Packet modulation schemes are totally different to and have nothing to do
with simple FSK, which was used in older HF transmission modes. It is therefore
IMPOSSIBLE to use the FSK modulator which can be found in some transceivers to
generate the signal. The Robust HF-Packet signal must always go the indirect way, which
is using the SSB modulator to generate the HF signal. This is of no disadvantage,
providing the transceiver is not overdriven.
Some useful hints to properly setup the transceiver:
• If possible use a 500 Hz IF-filter HF Packet-Radio. Never use a IF-filter with a smaller
bandwidth than 500 Hz! IF filter (SSB-filter) with wider bandwidths won´t cause problems
at all. Although the filtering by the DSP of the DSP TNC is always optimal, it is desirable
to prevent noise from "amplitude modulating" the desired signal through the AGC of the
receiver. Preventing undesired signals from the input of the DSP TNC also improves the
effective dynamic range.
• Under no circumstances use audio processors. The speech-compressor of the transmitter
will damage the signal in the same way as external DSP audio filters will do. These
external DSP audio filters create inpredictable signal propagation delays which are not
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