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1992-04-12
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Packet Radio Monitor v1.20
New features in respect to version 1.00
1. Packets are being sorted out according to source
and destination address. As the result data
streams exchanged by packet stations can be reconstructed.
2. "On line" tuning indicator - especially needed in HF mode.
To monitor packet radio traffic you need:
1. Radio receiver.
2. HamComm (or similar) interface.
3. This program
4. IBM PC/AT compatible - a fast one...
When you start PKTMON it asks you for:
1. COM port the HamComm interface is connected to.
Possible choices are COM1 and COM2.
2. Mode: HF or VHF (800 or 1000 Hz deviation) packet.
3. Whether to log bad CRC frames or not.
Even when logged, frames with bad CRC are not considered
for data streams reconstructions.
4. File name for unsorted packet log (press <return> for screen log)
5. File name for sorted log. Here you give the file name
but without extension. PKTMON creates several files with extensions
.0, .1, .2, etc. Each file carries the data stream between two stations.
.oth file stores uncategoried frames that is beacons and UI packets.
If you respond with just <return> the traffic sorting will be disabled.
After you answer the above questions PKTMON decodes (or at least attempts
to decode) incoming packets. To stop it press <return>.
Tuning indicator consists of two parts: amplitude display on the left
and tuning display on the right. When you tune in HF receiver
look at amplitude and try to make it as high as possible.
Usually it shows 6-7 when packet signal is being heard
ans 2-3 when there is only noise. You need to tune slowly and precise
and when you find where the maximum is you should already see
packets being decoded. Use the right display for fine tuning
in 10 Hz steps.
If the tuning indicator does not appear or it is being updated
only rarely it means that your PC is too slow.
In HF mode the input signal should be centered at 700 Hz.
The intention was to use CW narrow filter of about 500 Hz width.
However the FM demodulator will accept as well other center frequencies:
900, 1100, 1300, ... in 200 Hz steps but the higher the frequency the higher
interrupt load so your PC may run out of CPU...
The program should terminate when you press ENTER.
If it does not that is an indication that your PC is too slow...
Disconnect the audio and it will terminate.
What to do if your PC is slow indeed ? Try to use squelch
in FM mode to limit the amount of data your PC has to process.
PKTMON is written in Turbo Pascal v6.0
with some parts in Pascal's built-in assembler.
I tested it on 386/SX 20 MHz machine.
If you need some other AFSK packet modes tell me
what are the center frequencies, deviations and bit rates.
I try to incorporate them into PKTMON.
Pawel Jalocha
Rynek Kleparski 14/4a
PL-31150 Krakow (Poland)
e-mail: jalocha@chopin.ifj.edu.pl
jalocha@vxcern.cern.ch
jalocha@priam.cern.ch
p.s. PKTMON is free for non-comercial use.