giovedì 21 giugno 2018

VFT - T207 detector tool


This VFT signal was recorded in july 2016.


After some necessary "cuts" I isolated the FSk signal.




As showed on the pictures above I found the bits sequence on air...


Using the "T207-detector" coded by Antonio Anselmi and Christoph Mayer is was very simple to find out a T207 encoding in FSK bitstreams.

More info:
T207
GNU Octave, scientific programming language

73 de Ik1yde

mercoledì 20 dicembre 2017

HF Fax / JAPAN METEOROLOGICAL AGENCY-TOKYO, JMH

Japan Meteorological fax received via remote sdr ( KiwiSdr ).

Facsimile test chart

Facsimile test chart

500HPA HEIGHT, VORTICITY PROGNOSIS (24HOUR ) and SURFACE PRESSURE, PRECIPITATION PROGNOSIS 0440 AWJP 00 COASTAL WAVE ANALYSIS (24HOUR )

Meteorological satellite picture


850HPA HEIGHT, TEMPERATURE, DEW POINT 0320 ASAS 00 THE FIRST RETRANSMISSION OF 0240 DEPRESSION


More info about Japan Metereological Agency

mercoledì 6 dicembre 2017

M42


Russian diplomatic station heard some weeks ago on HF.


Fsk modulation with a symbol rate of 100 Bd and 500 Hz shift.


The bitstream after demod shows a typical 7-bit structure (5 bit + 1 bit START and 1 STOP bit).


By removing the start and end bits, we obtain sequences of 10 groups of 5 letters each as shown in the figure.


Fsk transmission followed by op chat in morse code.

venerdì 24 novembre 2017

Inmarsat D+ / Inmarsat's satellite paging system

Inmarsat D+ paging system received yesterday night on L-Band. This is a signal downlink from satellite.


The symbol rate is 4 symbols/sec and 5 bits / symbol ( 20 bps ).


Modulation is a 32-MFSK


"The main use of this technology nowadays is in tracking trucks and buoys and SCADA applications".





lunedì 20 novembre 2017

MIL188-110A transporting FED-1052 protocol


MIL188-110A waveform ( acf 200ms ) sending encrypted email data.


Output bitstream.


FED-1052 protocol.


CFB encryption.



Source about CFB

mercoledì 8 novembre 2017

802.15.4 IoT - Internet of Things...


"IEEE 802.15.4 is a technical standard which defines the operation of low-rate wireless personal area networks (LR-WPANs)". This signal and many other signal like this are easily recevible in our house with a simple antenna. Probably this is a ZigBee device working on 868 MHz ( european standard frequency ).


Modulation and symbol rate.


Burst sequence.


Packet frame: 199 bits: "32 bits synchronization + 8 bits packet delimiter + 7 bits PSDU lenght + 1 bit reserved service" followed by PSDU ( variable lenght from 0 to 127 bytes )


in the next post a more in-depth analysis.

martedì 7 novembre 2017

Nokia Adaptive Message Terminal

Another interesting signal heard some days ago.


Looks like an FSK modulation....


Symbol rate: 301 Bd


Shift ~ 755 Hz Yes ! it's a Fsk modulation...



Bitstream after demod.


Bandwidth: ~950 Hz

...yes, it's a Nokia Adaptive Message Terminal...

More technical info:

- Antonio Anselmi's blog
- radioscanner
- SigidWiki.com