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

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".

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.

D-STAR / streaming audio DV mode

This is a fragment of a D-STAR transmission.

Symbol rate : 4800 Bd

Modulation: GMSK

Bitstream after demod:

I found a structure frame of 72 bits + 24 bits. The first 72 bits constitutes the voice frame and the last 24 bits constitutes the "data frame" ( 96 bits for each slot ).

This is the D­STAR radio frame structure in DV mode.

HF ionospheric test ?

Transmission received this morning by many "utility listeners" on the 3600 and 7506 KHz. After a short analysis I found some useful info:

Pic. 1

Pic. 2

Pictures 1 and 2 show the whole signal.

Pic. 3

focus on unmodulated tone spacing ( ~ 1000 Hz ) and time duration ( ~ 1 sec ).

Pic. 4

Max used bandwidth: 20 KHz

Pic. 5

Tone-scale... nice image!

Pic. 6

Tone lenght : ~ 1 sec

Typical feature is the 10-tone scale that starts from the central frequency with steps of 1 Khz ( upper and lower frequencies ), up to a total of 20 Khz of busy band (± 10 KHz ). The signal reminds me some ionospheric tests ( like Arecibo... ) but this is only my opinion.... who knows....