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.




domenica 22 ottobre 2017

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.






-.-. --.-

MFSK-16 ( CIS )


MFSK signal heard today on 14894 Khz.


This transmission is classified as CIS MFSK-16.


Bw: ~ 2600 Hz



16 tone, 174 Hz



Baud rate: ~ 33 Bd