What is a Data Slicer?
A Data Slicer is like a modem. It takes audio signals from a radio and
converts them to a digital format and feeds the data stream to a computer
through the serial port. Data slicers decode FSK signals (Frequency
Shift Keying).
What will a Data Slicer do for me?
There are many digital signals on the airwaves that your scanner can receive but
can't decode. A Data Slicer can convert these signals to a format your
computer can understand. With the right software, you can view the
messages and system activity contained in these digital signals. Decoding
these digital signals opens up a whole new world of radio monitoring.
There are software programs for download on the Internet that can decode the
majority of these data signals.
What can be decoded?
There are many digital modes on the HF bands like SITOR, ASCII, BAUDOT, NAVTEX, SYNOP,
AMTOR, and many others.
The most exciting modes are in the UHF/800MHz bands like:
This
page can help you identify the digital signals you are hearing on your
radio.
What else do I need to make it all work?
1. You need a radio that covers the frequencies where the data signals are being
transmitted. Most digital signals in the HF (shortwave) bands can be
decoded by plugging the data slicer into the speaker jack. Most digital
signals in the VHF/UHF/800 MHz bands require a simple modification to your radio
called a discriminator tap (the CD included with the Super Data Slicer Package
has extensive details on how to do a discriminator tap).
Click
here for discriminator tap modification services.
2. You need a computer with at least one serial port (COM port). PC
CARD (PCMCIA) to Serial adapters will work fine (like this
one). USB to
serial adapters will only work if the software is Windows based. Some of
the best programs are DOS based and a USB adapter will not work for these
programs (they will not be able to see the virtual serial port). Most of
the decoding software will run on slower computers (fast 486's or slow
Pentiums). So if you have an old computer sitting around because it is too slow,
it will probably work perfect for a decoding machine. A DOS operating
system is fine, unless you want to run Windows based decoding software.
Windows 95, Windows 98, and Windows ME, work quite well running Windows decoding
programs and DOS programs in a DOS window. Windows NT/2000/XP will also
work, but there are a lot more challenges in getting a DOS based program to see
the serial port.
Will it work with just one scanner?
Trunker only needs one scanner to run (the scanner with the
discriminator tap). With a single scanner you can see on your computer all
the activity and frequencies as shown in the screen shot below. By adding
an optional second scanner that can be controlled by Trunker, you create a very
powerful scanning system. Trunker will tune the second scanner so you can hear
the audio of whatever active talkgroup has the highest priority (you can assign
100 different priority levels to the talkgroups). When a higher
priority talkgroup becomes active, Trunker instantly tunes the second scanner to
that talkgroup without waiting for the previous talkgroup to finish - this is
even better than "Priority scanning" on a Motorola radio!
Click Here for Tips on setting up
Trunker for the first time
|
How Does it Work?
Above is an example of a Trunk Tracking setup
using the Super Data Slicer and Trunker.exe to decode the data channel. The
Pro-2048 has a discriminator tap and feeds the data slicer the analog
signal. The data slicer converts the signal and feeds it to the computer's
serial port. Trunker.exe decodes the data stream and displays all system
activity on the computer screen, logging all frequencies used, all talkgroups
used, and all individual radio IDs used (among many other things). The
second scanner is optional and is controlled by Trunker.exe so you can hear the
audio (without the dual port Super Data Slicer, your computer would need two com
ports to follow the audio). It will follow whatever conversation has the highest priority (you can set
different priorities for all your talkgroups and if a higher priority channel
becomes active it will immediately interrupt the current channel). You'll
never miss important transmissions again!
A typical Trunker screen (above) shows: System
Type, Cell #, Tone, System ID, Freq list, Active Freqs, talkgroup, Radio ID,
Status, Affiliated radios, priority, text labels (you enter), and much
more. Trunker is a free (awesome) DOS program written by Neal R. Fildes. |
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