lunedì 30 ottobre 2017

STANAG-4538 circuit mode traffic


STANAG-4538 traffic spotted some days ago. 3G ( BW5 waveform ) used as link and 2G ( M188-110A waveform ) transporting data.


3G-2G switching


ACF: 67ms ( M188-110A ) / PSK-8 waveform



Output bitstream show evidence of citadel Harris encrypted data.

sabato 28 ottobre 2017

GMSK 6500 Bd

Heard today on 16248 KHz.....







Tks to "linkz" for the informations.

TADIRAN AutoCall

Looking in my archive i found this interesting system. AutoCall is a proprietary function of the Tadiran HF-6000 radio systems.


The signal is composed of two parts: a single tone followed by an MFSK-4.


Symbol rate: 125 Bd


MFSK modulation : 4 tones, shift 300 hz



Bitstream after demod ( 2 bits / symbol ).

giovedì 26 ottobre 2017

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.



mercoledì 25 ottobre 2017

S4285 / KG84

Voice/PSK traffic spotted this morning.




ACF: 106 ms ( in this case STANAG-4285 ).


Bitstream after demodulator, packet frame lenght: 64 bits.


Header structure: 64 bits ( kg84 ) followed by 128 bits key ( 64 bits x 4 + 64 bits x 4 ).

lunedì 23 ottobre 2017

MIL188-141A / UKE304 / XSS


Aircraft UKE304 requesting to XSS, RAF base in UK, Meteorological Air Report...




.....

[2017-10-23 11:58:05] [NORMAL MODE][TO][?][TO][?][CMD AMD][EGVN 230850Z 21005KT 9999 OVC008 13/12 Q1016 ][TIS][XSS][EOM]
[2017-10-23 11:58:16]
[2017-10-23 11:58:16] [NORMAL MODE][TO][?][TO][?][CMD AMD][TEMPO 6000 -RADZ SCT006 ][TIS][XSS][EOM]
[2017-10-23 11:58:42]
[2017-10-23 11:58:42] [NORMAL MODE][TO][?][TO][?][CMD AMD][TAF EGVN 230734Z 2309/2409 24008KT 9999 BKN010 ][TIS][XSS][EOM]

.......

[2017-10-23 11:59:34] [NORMAL MODE][TO][?][EOM]
[2017-10-23 11:59:37]
[2017-10-23 11:59:37] [NORMAL MODE][TIS][XSS][EOM]
[2017-10-23 11:59:44]
[2017-10-23 11:59:44] [NORMAL MODE][TO][?][TO][?][CMD AMD][ 3000 RADZ SCT003 ][TIS][XSS][EOM]
[2017-10-23 11:59:57]
[2017-10-23 11:59:57] [NORMAL MODE][TO][?][TO][?][CMD AMD][BECMG 23132315 FEW015 PROB30 ][TIS][XSS][EOM]
[2017-10-23 12:00:08]
[2017-10-23 12:00:08] [NORMAL MODE][TO][?][TO][?][CMD AMD][TEMPO 2315/2317 SCCT010 ][TIS][XSS][EOM]
[2017-10-23 12:00:23]
[2017-10-23 12:00:23] [NORMAL MODE][TO][?]

......

[2017-10-23 12:00:42] [NORMAL MODE][TO][?][TO][?][CMD AMD][TEMO 2400/2408 3000 -RADZ BKN004 ][TIS][XSS][EOM]
[2017-10-23 12:00:48]
[2017-10-23 12:00:48] [NORMAL MODE][TO][?][TO][?][EOM]
[2017-10-23 12:00:51]
[2017-10-23 12:00:51] [NORMAL MODE][TIS][XSS][EOM]




Whole session....

FSK / encrypted data

FSK waveform trasporting secure data - KG84



Shift: 850 Hz
Symbol rate: 75 Bd


Bitstream after demodulator.




2G-ALE

This is a 2G-ALE traffic example recorded some days ago.


The first signal ( red box ) is a MIL188-141A waveform ( also known as Automatic Link Establishment ALE ). During this procedure between the two stations there is an exchange of information about the quality of the received signal. After establishing the connection, the stations can continue with a low speed data exchange or alternatively, the ALE system can manually or automatically switch tasks to a system of different transmission FSK or PSK for high-speed or even voice data transmission. In this case is used a an high speed modem - PSK waveform ( yellow box ).


Looking the ACF value we can get some info about the system used. 200ms are typical of a MIL188-110A ( this is a necessary but not sufficient condition ! ).


After a brief analysis of the bits stream ( with a bits analyzer ), I found a 10 bits structure: 2 bits are used as packet frame delimiter and the last 8 bits are encrypted data.



Looking the first bits sequence we can identify the tipical "fingerprint" of the "Harris Citadel" encryption (*).


(*) source about Harris Citadel encryption: i56578_swl

domenica 22 ottobre 2017

188-110A / encrypted data

Two short 188-110A sequences trasporting encrypted data ( Harris Citadel ).

Chinese 4+4 parallel tone modem

I heard the signal two days ago on 16820 Khz.





300 Hz typical between the tones and 450 Hz between the two 4-tones groups.


Interleaved in time and frequency tones 4+7, 3+6, 2+5, 1+8

Symbol rate: 75 Bd for each tone.






Modulation: pi/4 DQPSK 

giovedì 19 ottobre 2017

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....

martedì 17 ottobre 2017

MFSK-16 (CIS ) variant 66 Bd

MFSK's day !

Heard on 12163 Khz one hour ago.
MFSK-16 with different symbol rate : ~ 66 Bd.

This is the same signal of the previous post but with different symbol rate spotted on a different frequency.






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