31 December 2016

a STANAG-4285 variant


The STANAG-4285 waveform is well defined by looking at ACF duration and frame structure of the signal (Fig. 1), unless the initial 100msec tones which are not provided by the standard (Fig. 2).

Fig. 1
Fig. 2
Data signaling is 600 bps but the S-4285 standard decoders do not recognize the SOM/EOM sequences using both short or long interleaving.  Using the short interleaving it's possible to get  a 128-bit period for the datalink protocol: data seem to be arranged in blocks separated by 6x128 bit headers (Fig. 3).

Fig. 3
Traffic is quite constant on 6931.0 KHz/USB, is not preceeded by ALE or selcall procedures and the strengths and durations of the messages lead to think to an ARQ system so it is likely a well-known channel by the receive peer.  The same signal was heard on 5097.5 KHz/USB two years ago and reported here in radioscanner forum: R_V_S talk about a Croatian source and it could be possible since they have the internal resources to implement modified/proprietary protocols as their CROZ S-5066 mail gateway.


https://yadi.sk/d/I_5mRuTM36B8xn 


25 December 2016

CIS MFSK-64 (32+32) 45Bd


I recently had the chance to have a good copy of MFSK-n signal previously reported here as a MFSK 68-tone (34+34). Well, according to my new measurements, I tend to reconsider it as a parallel 64-tone (32+32) signal: this way the shift of 46.9 Hz among the tones is closer or almost the same of  the apparent speed of 47 symbols/sec. 
PSK-8 9000Bd bursts (2 symbol element periods length) are sent each 1 second, possibly acting as sync (Fig. 1):  since the embedded PSK inserts, the signal occupies a bandwidth up to ~10KHz.

Fig. 1
It's worth noting that in the first half of the transfer a 3-tone symbols alphabet is used, while a 5-tone symbols alphabet (the most frequent in this wavefrom) is used in the second half, from time t1 (Fig. 2). In both the cases the speed of 45 symbols/sec remains constant (Fig. 3)


Fig. 2

Fig. 3
The measured 47 symbols/sec from SA likely results from the add of the two symbols due to the PSK-8 inserts.
The 64-tone solution can be easily seen by counting the tones over the -40dB threshold in the upper and lower part of the signal plotted in the FFT spectrum /Fig. 4).

Fig. 4
The number of the used tones remains constant, as well as the speed, for both the two alphabets (Figs 5,6) although the count of the grid in the second half of the signal (5-tones symbols) is more difficult.

Fig. 5
Fig. 6
Often you can see the CIS-3000 PSK-8 3000Bd modem before MFSK-64 as in Fig. 7: it's interesting to note that CIS-3000 and PSK-8 inserts have the same sub-carrier value (~5300 Hz) and it just matches the center of the MFSK-64 FFT spectrum (Fig. 8)

Fig. 7
Fig. 8
MFSK-64 is likely a Russian Intel parallel tones system as well as other MFSK and CIS-3000 could be employed as a sort of selcall. 


https://yadi.sk/d/WMnwnpN034qLZV 

23 December 2016

ICAO METARs TAFs sent over MIL 188-141 2G-ALE


This MIL 188-141 2G-ALE session  has been copied today 23 Dec. on 09019.0 KHz/USB starting from 1010 UTC. The ALE addresses are:  XSS, RAF base in Forest Moor UK belonging to DHFCS-net (Defense High Frequency Communication Service) and UKE304, RAF E3D AWACS Aircraft: respectively TAZ and NATO35 callsigns. The Comms  are conveyed by AMD commands which are embedded in 188-141. After the handshake, this is the first message sent by the Awacs, requesting METARs and TAFs (weather informations) for some airports in Cyprus identified by LCRA LCLK, and  LCPH:

LCRA - AKROTIRI 
LCLK - LARNACA/LARNAX 
LCPH - PAPHOS/BAF

TAZ DE NATO35 HELLO WE R RQSTING METARS N TAFS FP LCRA LCLK LCPH TVM
followed by the reply from ground:

DE TAZ WAIT ONE
something like "wait a moment..." then the requested weather informations for LCRA, LCLK, and LCPH are sent by TAZ (XSS)

LCRA 230850Z 14003KT 9999 6000E -SHRA SCT022CB BKN045 13/10 Q1019 BECMG 9999 FEW022CB
TAF LCRA 230732Z 2309/2403 09005KT 9999 BKN050 PROB 303
TEMPO 2309/2403 5000 TSRA SCT022CB

LCLK 230930Z 08007KT 9999 FEW020TCU 15/11 Q1020 NOSIG
TAF LCLK 230530Z 2306/2406 04008KT 9999 SCT020 BKN040 PROB40
TEMPO 2306/2406 5000 SHRA PROB330
TEMPO 2306/2406 VRB20G30KT 2000 TSRA SCT020CB
BECMG 2309/2312 21010KT
BECMG 2316/2319 33007KT


LCPH 230930Z 07006KT 9999 FEW0bkX30TCU SCT050 15/09 Q1019
TAF LCPH 230530Z 2306/2406 07008KT 9999 SCT020 BKN040 PROB40
TEMPO 2306/22406 5000 SHRAPROB30
TEMPO 2306/2406 VRB20G30KT 2000 TSRA SCT020CB
BECMG 2308/2311 24010KT
BECMG 2316/2319 03007KT

Transmission is terminated by:
THATS THE WX COMPLETED K


METAR (METeorological Air Report) is a format for reporting weather information which is predominantly used by pilots in fulfillment of a part of a pre-flight weather briefing, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. METAR is a common format and highly standardized through the International Civil Aviation Organization (ICAO) which allows it to be understood throughout most of the world.
A typical METAR contains data for the temperature, dew point, wind speed and direction, precipitation, cloud cover and heights, visibility, and barometric pressure. A METAR may also contain information on precipitation amounts, lightning, and other information that would be of interest to pilots or meteorologists such as a pilot report or PIREP, colour states and runway visual range (RVR). TAF (Terminal Aerodrome Forecast) complement and use similar encoding to METAR reports.
TAFs are produced by a human forecaster based on the ground. For this reason there are considerably fewer TAF locations than there are airports for which METARs are available. (quoted from Wikipedia)

22 December 2016

Logs

04096.0: ---: Unid USB 1835 USB STANAG-4197 ANDVT (07Dec16) (AAI)
04378.5: ---: Unid 1805 USB STANAG-4197 msgs (15Dec16) (AAI)
04618.0: BP25: German Police vessel Bayreuth, D 1738 USB MIL 188-141 2G-ALE handshake BPLEZs flwd by R&S G-2100 HF modem transporting RSX.25 login (18Dec16) (AAI)
04985.0: ---: Unid 0750 (cf) FSK 50Bd/850 (04Dec16) (AAI)
05120.0: OPL: Bosnia Herzegovina Defense, BIH 0818 USB MIL 188-141 2G-ALE calling GAA (21Dec16) (AAI)
05211.5: UD5I: Italian Military, I 0750 J3E/USB radio-checks with AD9W, G407, 4XCM, 6XQW, 11U7, Q67Z, ADRW (16Dec16) (AAI)
05321.5: STHQ01: NPRD-net, HRV 0900 USB MIL 188-141 2G-ALE calling K51 (01Dec16) (AAI)
05323.0: XS52: Algerian Military, ALG 0822 USB MIL 188-141 2G-ALE calling XS54 (21Dec16) (AAI)
05352.0: TYMT2: Spanish Police Toledo, E 0801 USB MIL 188-141 2G-ALE sounding (16Dec16) (AAI)
05401.0: KRAKOW: Polish MSWiA Krakow, POL 0822 USB MIL 188-141 2G-ALE calling WARSZAWA2 (05Dec16) (AAI)
05405.0: HN09: Algerian Military, ALG 0815 USB MIL 188-141 2G-ALE calling HN01 (21Dec16) (AAI)
05405.0: WG01: Algerian Military, ALG 0811 USB MIL 188-141 2G-ALE calling AT01 (09Dec16) (AAI)
05420.0: WG01: Algerian Military, ALG 0806 USB MIL 188-141 2G-ALE calling AT01 (09Dec16) (AAI)
05424.0: OP1: Bosnia Herzegovina Defense, BIH 0821 USB MIL 188-141 2G-ALE hadshake OPL flwd by FED-1052/B over MIL 188-110A (01Dec16) (AAI)
05424.0: OP1: Bosnia Herzegovina Defense, BIH 0821 USB MIL 188-141 2G-ALE handshake OPL then FED-1052B over MIL 188-110A (06Dec16) (AAI)
05424.0: OP4: Bosnia Herzegovina Defense, BIH 0855 USB MIL 188-141 2G-ALE hadshake OPL flwd by FED-1052/B over MIL 188-110A (01Dec16) (AAI)
05424.0: OPL: Bosnia Herzegovina Defense, BIH 0851 USB MIL 188-141 2G-ALE hadshake OP3 flwd by FED-1052/B over MIL 188-110A (01Dec16) (AAI)
05424.0: OPL: Bosnia Herzegovina Defense, BIH 0853 USB MIL 188-141 2G-ALE hadshake OP2 flwd by FED-1052/B over MIL 188-110A (01Dec16) (AAI)
05434.0: OSI: Polish Military, POL 0732 USB MIL 188-141 2G-ALE 3-way handshake DUM flwd by MIL 188-110A (14Dec16) (AAI)
05465.0: CM5: Algerian Air Force, ALG USB MIL 188-141 2G-ALE 2-way handshake COF flwd by MIL 188-110A (14Dec16) (AAI)
05708.0: ADW: USAF Andrews AFB, USA 0746 USB MIL 188-141 2G-ALE sounding (04Dec16) (AAI)
05838.0: ABC7: Croatian Military, HRV 0916 USB MIL 188-141 2G-ALE handshake ABK4 flwd by STANAG-4285 1200bps/L transporting STANAG-5066/HMTP off-line encrypted msg (20Dec16) (AAI)
05838.0: ABC7: Croatian Military, HRV 1021 USB MIL 188-141 2G-ALE handshake ABS5, voice radio-check then STANAG-5066 msgs over STANAG-4295 (06Dec16) (AAI)
05854.0: R26452: US Army Helo, UH-60L Black Hawk 0829 USB MIL 188-141 2G-ALE sounding (09Dec16) (AAI)
05854.0: RAPTOR: NATO MNBG-E net 0855 USB MIL 188-141 2G-ALE sounding (09Dec16) (AAI)
05879.0: RK33: Algerian Military, ALG 0846 USB MIL 188-141 2G-ALE calling RK35, rptd on 5875.0: (06Dec16) (AAI)
05898.0: ABC7: Croatian Military, HRV 0900 USB MIL 188-141 2G-ALE 3-way handshake ABS5 then MIL 188-110A transporting STANAG-5066 HMTP (08Dec16) (AAI)
05898.0: ABC7: Croatian Military, HRV 0906 USB MIL 188-141 2G-ALE handshake ABH3 flwd by STANAG-4285 1200bps/L transporting STANAG-5066/HMTP off-line encrypted msg (20Dec16) (AAI)
06208.4: XLB: Unid net 1819 USB MIL 188-141 2G-ALE 2-way handshake XLA (07Dec16) (AAI)
06224.0: T14: Unid 2106 MIL 188-141 2G-ALE sounding (22Dec16) (AAI)
06252.2: ---: Unid 0950 (cf) FSK-2 150Bd/250Hz KG-84 encrypted messages. Very strong in JN52 (07Dec16) (AAI)
06416.5: XNM: GBR-DHFCS, G 0850 USB MIL 188-141 2G-ALE handshake XSS flwd by a single MIL 188-110A shot (20Dec16) (AAI)
06510.0: P1O: Slovakian AF, SVK 1259  USB MIL 188-141 2G-ALE calling N1R (07Dec16) (AAI)
06522.6: ---: Unid 0949 USB THALES Robust Mode MFSK-8 125Bd (07Dec16) (AAI)
06550.0: R26308: Sikorsky UH-60L "Black Hawk" 90-26308 0851 USB MIL 188-141 2G-ALE sounding (15Dec16) (AAI)
06745.5: AC01: Algerian Military, ALG 0852 USB MIL 188-141 2G-ALE calling XV01 (19Dec16) (AAI)
06748.0: CHARLY46: Italian AF 46th Air Brigade, I 0940 USB MIL 188-141 2G-ALE calling 48 (07Dec16) (AAI)
06772.0: LIS: Unid net 0752 USB MIL 188-141 2G-ALE calling WTF (19Dec16) (AAI)
06773.0: ---: Unid 1015 USB THALES Robust Mode MFSK-8 125Bd (09Dec16) (AAI)
06775.0: ---: Unid 0954 (cf) FSK-2 300Bd/500, 255/360 bit period (07Dec16) (AAI)
06802.0: PA01: Algerian Military, ALG 0825 USB MIL 188-141 2G-ALE calling PY01 (09Dec16) (AAI)
06806.0: PY30: Algerian Military, ALG 1108 USB MIL 188-141 2G-ALE calling KA35 (08Dec16) (AAI)
06831.0: D20: NPRD Net, HRV 1123 USB MIL 188-141 2G-ALE sounding (08Dec16) (AAI)
06831.0: V08: NPRD Net Velika Mlaka, HRV 0949 USB MIL 188-141 2G-ALE sounding (07Dec16) (AAI)
06831.0: Z01: NPRD Net, HRV 1122 USB MIL 188-141 2G-ALE sounding (08Dec16) (AAI)
06838.5: EAGLEXRCHALLEN: Unid 0903 USB MIL 188-141 2G-ALE calling BAYONXUQCHALLE (07Dec16) (AAI)
06854.5: 123: Algerian Military (test call ?), ALG 1753 USB MIL 188-141 2G-ALE calling XS50 (15Dec16) (AAI)
06854.5: PY01: Algerian Military, ALG 1117 USB MIL 188-141 calling DR01 (08Dec16) (AAI)
06854.5: XS56: Algerian Military, ALG 1117 USB MIL 188-141 2-way handshake PY5 (08Dec16) (AAI)
06870.0: PY10: Algerian Military, ALG 1116 USB MIL 188-141 2G-ALE calling KB2 (08Dec16) (AAI)
06884.0: POZNAN: Polish MSWiA, POL 1112 USB MIL 188-141 2G-ALE calling KRAKOW (08Dec16) (AAI)
06902.6: KWS95: US Dept of State station 0948 USB MIL 188-141 2G-ALE calling KWX57 (07Dec16) (AAI)
07499.9: ---: Unid 0945 (cf) BPSK 127.3:Bd (06Dec16) (AAI)
07500.0: BAR: Unid net 0927 USB MIL 188-141 2G-ALE calling 3RT (06Dec16) (AAI)
07500.0: BAR: Unid net 0929 USB MIL 188-141 2G-ALE global AllCall (06Dec16) (AAI)
07505.8: XLB: Unid net 0749 USB MIL 188-141 2G-ALE calling XLA (06Dec16) (AAI)
07526.0: BSK: Algerian AF, ALG 0815 USB MIL 188-141 2G-ALE 2-way handshake CM4 then MIL 188-110A (09Dec16) (AAI)
07535.0: WG01: Algerian Military, ALG 0814 USB MIL 188-141 2G-ALE calling AT01 (09Dec16) (AAI)
07558.0: JP20: Algerian Military, ALG 1306 USB MIL 188-141A 2G-ALE calling PY20, rptd on 7530.0: (06Dec16) (AAI)
07604.0: KA31: Algerian Military, ALG 1625 USB MIL 188-141 2G-ALE calling PY30 (30Nov16) (AAI)
07611.0: PY40: Algerian Military, ALG 1259 USB MIL 188-141A 2G-ALE calling FQ47 (06Dec16) (AAI)
07653.0: ---: Russian Intel/Diplo, RUS 1255 USB CIS MFSK-16 33.3:3Bd 175Hz (09Dec16) (AAI)
07748.0: ---: Russian Navy, RUS 1237 (cf) CIS Navy "Akula" FSK 500Bd/1000 (06Dec16) (AAI)
07814.3: C3: Moroccan Military, MRC 1621 USB MIL 188-141 2G-ALE calling R3 (30Nov16) (AAI)
07840.0: SRS: Unid net 0902 USB MIL 188-141 2G-ALE calling 25B (06Dec16) (AAI)
07840.0: SRS: Unid net 1253 USB MIL 188-141 2G-ALE calling BPI (06Dec16) (AAI)
08322.2: ---: Unid 0902 USB STANAG-4285 300bps/L KG-84 encrypted messages (14Dec16) (AAI)
08334.2: ---: Unid 1455 USB STANAG-4285 600bps/L KG-84 encrypted messages (14Dec16) (AAI)
08815.0: R26308: Unid (US/NATO helicopter?) 1411 USB MIL 188-141 2G-ALE sounding. Also heard on 9005.0: and 8850.0: (03Dec16) (AAI)
08815.0: RAPTOR: NATO MNBG-E (Lockheed Martin F-22?) 1349 USB MIL 188-141 2G-ALE sounding. Also heard on 9005.0: and 8850.0: (03Dec16) (AAI)
09066.5: SABERXR3G: Unid net 1329 USB MIL 188-141 2G-ALE calling WARWA1MI3G (02Dec16) (AAI)
09066.5: WARHOLO73G: Unid net 1244 USB MIL 188-141 2G-ALE calling SABERXR3G (02Dec16) (AAI)
09101.5: SABERXR3G: Unid 1438 USB MIL 188-141 2G-ALE calling WARHORS3G (03Dec16) (AAI)
10174.0: ---: Russian Intel/Diplo, RUS 1300 USB CIS MFSK-16 14.6:6Bd 175Hz (30Nov16) (AAI)
10220.0: 2151: Unid net 0955 USB MIL 188-141 2G-ALE calling 2157 (30Nov16) (AAI)
10248.0: ---: Unid 1013 USB STANAG-4285 600bps/L KG-84 encrypoted (30Nov16) (AAI)
10404.5: ---: Australian MHFCS net, AUS 1335 (cf) MSK 600Bd/340 (14Dec16) (AAI)
10425.0: XW0: Unid net 1312 USB MIL 188-141 2G-ALE calling CON (05Dec16) (AAI)
10429.0: 2169: Unid 1027 USB MIL 188-141 2G-ALE calling 2153 (10Dec16) (AAI)
10620.5: 01012016: Unid (Algerian aircraft?) 0827 USB MIL 188-141 2G-ALE calling CM6 Algerian AF (04Dec16) (AAI)
10930.0: ---: Unid prob. Turkish Navy, TUR 0835 USB STANAG-4285 (04Dec16) (AAI)
10935.0: ---: Ukraine Mil, UKR 0945 USB MFSK-4 (double FSK) 96Bd/500 (tones at -750, -250, +250, +750) (20Dec16) (AAI)
11158.5: ---: Unid 0916 USB (cf +1500 Hz) R&S ALIS 228.6:5Bd/200 called address 410 (19Dec16) (AAI)
11217.0: UKE304: RAF E3D AWACS Aircraft 1508 USB MIL 188-141 2G-ALE sounding (14Dec16) (AAI)
11552.0: ---: Russian Intel, RUS 1008 (cf) MFSK-68 (34+34) + QPSK 2400Bd 10KHz wide-band inserts (20Dec16) (AAI)
12065.0: 1314: Unid, prob. Moroccan Civil Protection, MRC 0931 USB MIL 188-141 2G-ALE sounding (18Dec16) (AAI)
12121.0: ---: Russian Militay, RUS 0846 USB CIS-112 OFDM 112-tone modem BPSK 22.22Bd (16Dec16) (AAI)
12142.0: ---: Russian Military, RUS 1508 USB CIS-3000, PSK-8 3000Bd serial modem flwd by MFSK-64 (32+32) 45Bd (22Dec16) (AAI)
12157.0: 782: Algerian AF 782e RĂ©giment des Fusiliers Commandos de l’Air (RFCA) 1406 USB MIL 188-141 2G-ALE calling CM4 (11Dec16) (AAI)
12160.0: A2: Royal Moroccan Army, MRC 0946 USB MIL 188-141 2G-ALE calling C3 (19Dec16) (AAI)
12160.0: IR4: Royal Moroccan Army, MRC 0946 USB MIL 188-141 2G-ALE calling C3 (19Dec16) (AAI)
12160.0: T40: Royal Moroccan Army, MRC 1017 USB MIL 188-141 2G-ALE calling C3 (19Dec16) (AAI)
12164.0: ---: Russian Military, RUS 1005 USB CIS-45 OFDM HDR modem v1 BPSK 33.3Bd 62.5Hz (13Dec16) (AAI)
12173.0: ---: Russian Intel, RUS 0830 USB CIS FTM-4, MFSK-4 150Bd (effective 37.5:Bd) 4000Hz modem (tones at: -6, -2, +2, +6 KHz) (19Dec16) (AAI)
12190.0: 01012016: Algerian AF, ALG 0838 USB MIL 188-141 2G-ALE calling CM6 (22Dec16) (AAI)
12209.0: ---: Russian Militay, RUS 0840 USB CIS-45 OFDM 45-tone HDR modem v2 QPSK 40Bd 62.5Hz (20Dec16) (AAI)
12226.0: ---: Unid (prob. Bulgarian Diplo Net) 0900 USB RFSM-8000 modem with data-masking (16Dec16) (AAI)
12369.2: ---: Unid 1035 USB STANAG-4285 600bps/L KG-84 encrypted messages (13Dec16) (AAI) [1]
12372.0: ---: Unid 1030 USB STANAG-4285 600bps/L KG-84 encrypted messages (13Dec16) (AAI) [1]
12376.0: ---: Unid (prob.Russian Navy occasional test, RUS) 1423 (cf) FSK-2 50Bd/1000, preamble: 2x70 bit repeated sequences (11Dec16) (AAI)
12424.8: ---: Unid 0808 (cf) FSK-2 200Bd/400, not ARQ-E(3) mode (13Dec16) (AAI)
12459.0: 8591: Turkish Civil Defense Tekirdag, TUR 1423 USB MIL 188-141 2G-ALE sounding (11Dec16) (AAI)
12477.5: ---: Unid 1025 USB STANAG-4285 600bps/L KG-84 encrypted messages (13Dec16) (AAI) [1]
12499.8: ---: Unid 1020 BPSK modem 125Bd (11Dec16) (AAI)
12567.0: ---: Unid (Eyptian Army ?) 1246 USB HARRIS AutoLink-I 1G-ALE handshake flwd by MIL 188-110 App.B 39-tone OFDM modem (21Dec16) (AAI)
12580.5: OSY: SailMail Node Brugge, BEL 1055 USB (cf + 1500Hz) PacTOR-III wkg US Sailing Vessel WIND PONY "WDC6710 de OSY" (11Dec16) (AAI)
12898.0: ---: Russian Militay, RUS 0915 USB CIS-60 OFDM 60-tone modem p/4 DQPSK 30Bd (16Dec16) (AAI)



19 December 2016

PSTN V-series modem over a radio link ?


This transmission has been copied on 6421.5 KHz/USB at 0808 UTC and consits of five parts:
1) initial FSK 300Bd call and link negotiation, between the calling and the answering modem;
2) PSK 1200Bd data transfer from the calling modem;
3) FSK 300Bd from the answering modem (a mode switch request ?);
4) PSK 600Bd data transfer from the calling modem;
5) FSK 300bd likely as ACK and link disconnect;
Each FSK/PSK frame is preceeded by a 1500Hz short tone (Fig. 1) and looking at the strength of the PSK frames they seem to be sent by the calling modem.

Fig. 1
The FSK signal initialing the link has a speed of 300Bd and shift of ~170Hz (Fig. 2). Once demodulated,  it exhibits a 10-bit length period and matches the 8N1 format: one start bit, one stop bit, no parity and 8 data bits (Fig. 3).
 
Fig. 2

Fig. 3

Speeds, carriers and PSK constellations related to the PSK frames are shown below in Figs 4,5 (note the amplitude failure in the initial 1200Bd PSK frame that impairs its study):

Fig. 4
Fig. 5

It's interesting to note that the waveforms of the PSK frames match some of the ITU-T V series recommendations for data communication modems over the Public Switched Telephone Network (PSTN):
1200 Baud, 1800 Hz carrier, PSK-4 (2400 bps gross) --> ITU-T V.26
 600 Baud,  1200 Hz carrier, PSK-4 (1200 bps gross) --> ITU-T V.22 (Bell 212A)
(ITU-T recommendations can be read here)

My friend KarapuZ, who pointed me to ITU modems, heard some other V-serie modem on HF: maybe some tests or arrangements as proof-of-practice about the feasibility of such unusual solution (PSTN modem over HF). It's worth noting what seems to be a sort of adaptive solution, the 1200-600 Baud switch, and that the military often use such modems but on VHF repeaters.
Comments are welcome.





15 December 2016

HARRIS proprietary Autolink-I (1G-ALE)


Very interesting ALE session consisting of HARRIS Autolink-I handshake (a proprietary waveform) followed by a data transfer using MIL 188-110 App.B 39-tone OFDM modem and link disconnect: since the used technology, 1G-ALE and 39-tone, the session is almost a sort of HF flashback. The transmission has been heard on 12567.0 KHz/USB at 1140 UTC 13 December, most likely from Moroccan Military.

The Harris Autolink-I system was one of the first adatptive and automated HF systems available and was implemented in the Harris RF-7110 controller, then it was upgraded to a RF-7210A Mil Spec Autolink-II. The basic difference between the first and second generation units is in the type of utilized addressing:  call signs in the 1G controllers are limited to numerical digits while 2G controllers can employ up to 15 alphanumerical identifiers.

Fig. 1
Autolink-I employs an FSK waveform modulated at 200 Baud and shift of 200 Hz (Fig. 2). Structure is very similar to Harris RF-3560 Selcall. Preamble is a sequence of reversals and its duration is proportional to the number of channels in use so receivers have a chance to lock on the signal while scanning. Then, info is about 800 ms. and consists of some control words and 4 digits numeric call sign (Fig. 3). In case of group call to test channel conditions, answers are slotted.

Fig. 2
Fig. 3
As said, the data transfer is achieved with MIL 188-110 App.B, a 39-tone OFDM waveform introduced with the first release of 188-110 Standard and not recommended for new systems by the 3rd release (188-110C, September 2011). The modulator output consists of 39 QDPSK data tones which have a constant modulation rate of 44.44 Bd for all standard input data signaling rates from 75 to 2400 bps, plus an unmodulated tone for Doppler correction (Fig. 4).

Fig. 4

14 December 2016

unid FSK 200Bd/400


Yet another unidentified, and unknown to me, FSK waveform copied on 12424.8 KHz (cf) at 0808 UTC. Key parameters are 200 Baud as manipulation speed and shift of 400 Hz (Fig. 1). These values match one of the possible ARQ-E3 settings but decoding does not produce outputs so the signal doesn't belong to such waveforms family.
This same signal is reported in radioscanner.ru forum, you may read the topic and get more info here.

Fig. 1
As a side notes, its spectum has a characteristic pattern (Fig. 2) and working on the period length it's possible to get the value of 896 bit which is likely the frame structure (Fig. 3). Unless erorrs, the frame consists of 56-bit  of known symbols (sync and  ) and 840-bit room allocated for unknwon symbols (data block). 

Fig. 2
Fig. 3

13 December 2016

unid FSK 50Bd/1000 (prob. CIS Navy occasional test)


Strong - and odd - signal copied on 12376.0 (cf) at 1423 UTC on 11 December. This is probably a totally occasional test since the used fequency and some other points as below. The signal exhibits numerous spurious in the AM detector output (Figs 1,2) and maybe the cause is the failure of the filter sitting just after the FSK modulator. This is why I filtered and re-filtered the signal in order to get something usable about baudrate and shift values.

Fig. 1
Fig. 2
The SA "scanraster method" shows 50 symbols/sec as the most probable value of the modulation speed, altough this frequency is not stable (Fig. 3). After filtering the signal to 50Bd value, it's possible to get a 1000Hz value for the frequency shift (Fig. 4).
Fig. 3
Fig. 4

Assumed 50Bd/1000Hz as the key values, I proceeded to demodulate the signal using the SA FSK demodulator and with the precious advices and comments from radioscanner.ru friends Karapuz and Cryptomaster.
It's worth noting the presence of 2 x 70 bit repeated sequences in the preamble, as in Fig. 5, which resembles the  CIS Navy T-600 modem (ACF = 70 bit in the preamble only) although the constant 50Bd speed and the shift of 1000 Hz is quite rare for such modem (typical shifts are: 200, 250 and 500 Hz). Also note as the End Of Transmission "000100" sequence contains at least 4 EOT characters and the 4:3 ratio alphabet code (Fig. 6).  It's worth noting that two identical sequences of 70 bits are also intended for installation of keys of a ciphering machine, Cryptomaster say.

Fig. 5
Fig. 6
 


unid FSK 300Bd/500, 255/360 bit period


The signal was copied on 06775.0 (cf) at 0954 UTC of 7 December. The FSK-2 modulation exhibits a constant 300 symbols/sec speed and shift of 500 Hz (Fig. 1).

Fig. 1
The most interesting feature is the switch of the period lenght most likely in corrispondence of switching from idle and traffic mode. In the fist case the ACF has the value of 850.55 msec that corresponds to a 255-bit period length (Figs 2,3):

Fig. 2
Fig. 3
In the second case, likely when the signal transports data, the ACF exhibits the value of 200.13 msec that corresponds to a 360-bit period length (Figs 4,5) or, better, to a 60-bit frame which is repeated six times.

Fig. 4
Fig.5