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cars, chameleons, networks, and other stories (part II)

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In the first part of this post there were the cars, here are the chameleons: such name is not related to the ALE Addresses but rather to the configuration of the stations. A third part will follow in case of news or updates.
The two following networks, although they exhibit different behaviors, share some aspects which lead to think to the same source/organization or at least to the same Country. As said in the first part, the purpose is only hobbystic; sensitive and confidential messages contents, if any, are anyway not published. I'm interested on the way the "boxes" travel and NOT on their content.

AB-net
Stations and ALE addresses of this network are: ABD1, ABG6, ABF2, ABS5, ABK4, ABH3, and ABC7 that acts as net-control. Transmissions are scheduled on tuesday and thursday from about 0730 UTC and usually follow the schema link-send-terminate. Links are initiates by ABC7 and always in the same order, ie: ABD1 first then, ABG6, ABF2, ABS5, ABK4, and ABH3 as last. Other than 188-141A for ALE, STANAG-5066 is used for messaging and STANAG-4285 as HF waveform (fig. 1), settings are 1200bps and short interleaver. I monitored this net on 5838.0 KHz/USB, that seems to be the main channel, but other frequencies are also used.

fig. 1
In the firts loop, stations are contacted by ABC7 for a radio-check, then  in case the net-control has messages to send, the stations are again contacted and always in the same order. Sometimesthe sending phase follows the radio-chek so that the stations are worked one time only, the sending is always preceeded by a voice-exchange of a pair of authentication keys according to the sequence diagramof fig. 2. A common phrasebook for telecommunications, in english, is strictly used.

fig. 2 - sequence diagram
The authentication keys consist of 4 numeric digits for the "my-auth-id" key and 2 numeric digits for the "auth-id" key , eg:

ABC7: alpha bravo x y this is alpha bravo charlie seven, authenticate 79
ABXY: alpha bravo charlie seven, this is alpha bravo x y, my authenticate 6843, authenticate 74
ABC7: this is alpha bravo charlie seven, my authenticate 2895
ABXY: ok send your message


A fter finishing sendingthe message, the net-control station asks the receiver peer to confirm the message-number then link is terminated and the next station in turn is contacted.

fig. 3 - 188-141A 3-way handshake and Auth keys exchange
The messaging system use the HBFTP protocol to deliver compressed e-mail files, COMSEC devices are not present(unclassified messages?) so, once removed STANAG-4285 and STANAG-5066 overheads, important clues and information can be drawn from an examination of the e-mail headers (fig. 4).

fig- 4
The sender and receiver stations belong to the e-mail domain 123 (point 1) and it's the common domain of all the stations of this network.The message has been received from, and by,the same host whose name islinux.site; "CROZ ESMTP/HMTP Gateway"most likely is the name of the STANAG-5066 application (point 2).  The IP address in the field "Received from" is 127.0.0.1 or localhost (not wired to a LAN ?).
The hostnameand the e-mail client fingerprint (point 4) clearly reveal that they use a Linux system, specifically: SUSE Linux 3.1.14. Indeed, the mention of chameleons I adopted  just derives from the official logo of SUSE.
The system language is the plain en-US without  language/keyboard customization.

The use of Linux is per se an interesting and peculiar element of this network, but it's not the only one.  The emailincludes one attached jpeg/image file whose name is "PRILOG 5 - PRILOG ZA SLANJE E-MAILA.jpg". This language suggest a Slavic origin (google-translator), as confirmed by the system timezone at point "3" (+0200), time-zone and especially the language restrict the candidate Countries to two: HIB and HRV. Anyway, the most surprising fact is that the e-mails I decoded have that same attached filename although it refers two images, in other words  they always use the same name for the attachments (fig. 5).

fig. 5 - two e-mails, different ricipients but same attached filename
On my side I can't rebuild the original images from the received S-5066 fragments but I can see at least the upper part of such images:they are always the same (fig. 6), although the image "B" is the most used in the attachments.

fig. 6
The reasons behind such way to comunicate are obscure: test? steganography?.., difficult to state unless speculations

In the above fig. 2 we have seen that the net-control stations asks a confirm of the received message-number: this a progressive number and matches thesubject of the corresponding e-mail. The message-number is initialized to a new initial value at each day and assigned to the subject of the e-mail sent to the first station inthe calling list (ie: ABD1, user1@asdf.123) and then is incremented by one at each step (fig. 7).

fig. 7
The choice of the initial value is apparentlyodd: fig. 8 is an example
06 Oct: initial value 600
11 Oct: initial value 603 
13 Oct: initial value 508
18 Oct: initial value 610  

fig. 8


5054-net 
I spotted a QRG, 5054.0 KHz/USB, where stations of this network do not use 188-141A before messages sending and traffic is less frequent, not to say sporadic.  STANAG-5066 HMTP protocol is used instead of HBFTP (fig. 9) and, as for the AB-net, STANAG-4285 is the transporting HF waveform. The lack of the ALE phase is quite odd since the heard transmissions are not bcasts but rather PtP messages: or links are negotiated in other channels/way or receivers are always in listening state. For sure, no 188-141A means no ALE Addresses to collect from this network. 

fig. 9 - HMTP-66 protocol
By a quick examination of the e-mails headers (fig. 10) it's easy to see that this network belongs to the same organization/authority of the previous AB-net: same OS (Linux SUSE), same STANAG-5066 application (CROZ ESMTP/HMTP Gateway) and - above all - same attachment filename (PRILOG 5 - PRILOG ZA SLANJE E-MAILA.jpg) can't be a coincidence.

fig. 10

Addresses and origin/owner of the networks
I never heard e-mail exchanges between the two nets but only e-mails sent from linux-a5kz to the other stations of AB-net and e-mails sent from linux-2o6y.site to other stations of 5054-net: this leds to think that these are the main stations of their respective networks.It's interesting to pay a look at the e-mail addresses of the two newtorks:

ALE  e-mail address
[AB-net]
ABC7 user1@asdf.123
ABD1 user1@sdfg.123
ABG6 user1@dfgh.123
ABF2 user1@fghj.123
ABS5 user1@ghjk.123
ABK4 user1@jklp.123
ABH3      ?

[5054-net]
  -  user1@aysxd.111
  -  user1@lost62.111
  -  user1@dres32.111
  -  user1@fejk8.111


As expected, the networks belong to two different e-mail domains "123" and "111": behind such choice there is surely acertain logic but unfortunately do not offer any clue for identification.
AB-net seems to use non-sense (?) alphabetical addresses (asdf, sdfg,...) while 5054-net seems to use a sort of "structured" names (lost62, dres,32, fejk8,...).  It's worth noting that the AB-net addresses, if listed in the order of the calling list,  exhibit a left-shift of 3 letters. According to this schema, ABH3 could have the address user1@klpq.123 (m,n,o seem to be not used).

 
A big help in the identification of the source is given by the examination of the collected STANAG-5066 nodes addresses:

ALE  Stanag-5066 address e-mail address
[AB-net]
ABC7 006.008.001.039     user1@asdf.123 (ncs)
ABD1 006.008.004.166     user1@sdfg.123
ABG6 006.008.004.165     user1@dfgh.123
ABF2 006.008.006.226     user1@fghj.123
ABS5 006.008.008.215     user1@ghjk.123
ABK4 006.008.002.144     user1@jklp.123
ABH3 006.008.002.055          ?

[5054-net]
  -  006.008.004.165     user1@aysxd.111 (ncs)
  -  006.008.003.033     user1@lost62.111
  -  006.008.003.036     user1@dres32.111
  -  006.008.003.037     user1@fejk8.111



About the assignments of the STANAG-5066 addresses, the global-regional blocks are defined by the 4 most-significant bits of the full length address (i.e., the first element w of the dotted-decimal form w.x.y.z): from fig. 11, 6.x.y.z is assigned to Europe. 

fig. 11
Within the global-regional blocks, specific 5066 addresses are assigned to individual Nations using the second element “x” of the dotted-decimal address form w.x.y.z.
Now, what european nation matches6.8.y.z?
The answer is in Table N-6 "National Address Schema" STANAG-5066 Edition 3 Annex N: 5066 is a NATO unclassified document that may circulated freely and is available on:
http://nso.nato-int/nso/zPublic/stanags/CURRENT/5066Ed03.pdf
Sadly, no part of S-5066 Edition 3 can be publishedbut the mentioned Table N-6 matches the "proposed allocations" which are visible at page 14 (here reported in fig. 12) of  a very interesting pdf file freely downloadable from: http://www.hfindustry.com (note that NC3A,NATO C3 Agency, is now NCIA or NATO Communications and Information Agency).

fig. 12

It's worth noting that the stationsdfgh.123 and aysxd.111 exhibit the same S-5066 address 006.008.004.165, i.e. the same node: as far as I know a certain S-5066 address should not be shared by two or more nodes (duplicate address) hence we face the same physical node. Looking at the "Received"headers of one e-mail sent byaysxd.111 (fig. 13) we see thatthe e-mail is originated (from) and received (by) the same host linux-2o6y.site: this means that the e-mail client and the S-5066 gateway applicationare running inside that same host. Moreover, the IP address 127.0.0.1 (which refers the sender) is the address of the localhost: this means that the host linux-2o6y.site, i.e. the 006.008.004.165 S-5066 node, is not wired to a LAN.

fig. 13
Keeping in mind that a node is generally assumed to include the HF modem and radio (and cryptographic) equipment required for communications, a possible explanation could be the configuration in fig. 14, that also clarifies the lack of "cross-messaging" between AB-net and 5054-net: such traffic is handled "inside" the hosts. Unless they assigned the same S-5066 address to two distinct S-5066 nodes or use some other configuration that I do not know.
 
fig. 14

Rockwell-Collins HF Messenger allows a such configuration (fig. 15) in which two clients, belonging to different domains (i.e. two e-mail accounts), sharethe same S-5066 resource. Anyway, this is not our case since HFM only run on Windows-based pc and we face a Linux based nodes (SUSE Linux 3.1.14).

fig. 15


STANAG-5066 gateway application
The S-5066 application running in the Linux gateway nodes add the string"CROZ ESMTP/HMTP gateway" in the received-by header, most likely its "fingerprint":


It is an application that acts either as Extended SMTP server (on the LAN side) or as HMTP gateway (on the HF network side). They do not use a Stanag-5066 applications from the most "popular" manufacturers in the place:

supplierproductWindowsLinuxnotes
HarrisRF-6750W*-
IsodeIcon 5066**(development, not released)
RapidMRS66**
Rockwell-CollinsHFM*-
Rohde & SchwarzR&S 5066*-(client part in Java)
Selex (Leonardo)MDH*-
Thales-*-(client part in Java)

but rather the MoD preferredto havea proprietary product, entrusting the development of the application to CROZ, an IT Company located in Zagreb and Belgrade http://croz.net/en/, as contractor partner in the project. The result of this collaboration is the NATO Stanag-5066 compatible application named CroS5066 (fig. 16).


fig. 16 - CroS5066 schema
The mean features of the product can be read in their pubblication "CRO FYI" of  September 2009, page 14: the publication is available for reading and download on their web site:
http://croz.net/fyi/fyi-by-croz-broj-7/ 
CroS5066 is fully interoperable with other S-5066 systems, positive tests were made during NATO exercises Combined Endeavor 2008 (Lager Aulenbachhere, Germany and Lora Naval Base in Split, Croatia).

(to be continued)

Unid BPSK 1500Bd (prob. Chinese modem)

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Unid modem (prob. Chinese origin) using BPSK modulation at 1500 Baud and 1500 Hz sub-carrier. Since the alternation of frames with different strength, this may be a duplex channel.

fig. 1
fig. 2
fig. 3
Once demodulated, the analysis of the bitstream reaveals an interesting 3 bit structure (fig. 4): my friend Karapuz suggested to try a differential (relative) decoding of the signal.

fig. 4
Differential decoding can be obtained directly by running the proper tool of  the bit-editor or by demodulating the signal using the SA demodulator with option "Diff 1" as in fig. 5

fig. 5
Results are similar and in the output bistream, visually more logical, is visible the sync bit and the two data bits (fig. 6).

fig. 6


Turkish Mil, FSK 300Bd/400Hz KG-84C

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Weak signal heard on 5115.5 KHz, central frequency, at 0549 UTC. Analysis with SA reveals an FSK signal running at 300Bd and 400 Hz shift.
fig. 1
fig. 2
Once demodulated, the presence of the KG-84C 64-bit sync pattern (fig. 3)  leads to think about a NATO partner Nation: looking at precedent posts,  most likely the signal belongs to the Turkish  FSK waveforms.
 
fig. 3


https://yadi.sk/d/QXv7FXiYxdbjH

Logs

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03806.5 OE3XEC: Amsstetten AUT, 0754 WinLink traffic (23Oct16) (AAI)
05115.0 ---: Turkish Mil, TUR 0549 (cf) FSK 300Bd/400, KG-84C encrypted (24Oct16) (AAI)
05140.0 ---: Russian Mil (prob. AF) 0602 J3E/USB female voice comms (24Oct16) (AAI)
05182.0 ---: Unid 0722 R&S ALIS 228.65Bd/200 calling address 2190 (25Oct16) (AAI)
05210.0 BU4: Roumenian Police Bucuresti, ROU 0602 USB MIL 188-141 2G-ALE handshake TUL flwd by MIL 188-110A (19Oct16) (AAI)
05211.5 6GW0: Italian Mil, I 0647 J3E/USB radio-check with FB4T, 0WPF, Q77V, 3X0N, Q67Z (25Oct16) (AAI)
05258.0 J62: Moroccan Mil, MRC USB MIL 188-141 2G-ALE sounding (19 Oct16) (AAI)
05316.0 K1U: Slovakian AF, SVK 0637 USB MIL 188-141 2G-ALE calling Z1V (25Oct16) (AAI)
05316.0 P1O: Slovakian AF Prezov, SVK 0637 USB MIL 188-141 2G-ALE calling Z1V (25Oct16) (AAI)
05316.0 S1L: Slovakian AF, SVK 0637 USB MIL 188-141 2G-ALE calling Z1V (25Oct16) (AAI)
05316.0 Z1V: Slovakian AF Zvolen, SVK 0637 USB MIL 188-141 2G-ALE calling S1S (25Oct16) (AAI)
05340.0 LY01: Algerian Mil, ALG 0549 USB MIL 188-141 2G-ALE calling PY01 (26Oct16) (AAI)
05352.5 HG7BHB: propagation beacon, HUN  0545 CW "VVV DE HG7BHB  QTH JN97LE 34SF PWR 50W" (24Oct16) (AAI)
05371.5 9A3WD1P: Global ALE HFnet 0630 USB MIL 188-141 2G-ALE sounding (22Oct16) (AAI)
05400.0 DG501D: French Navy, F 0737 USB 188-141 2G-ALE handshake DG401D flwd by STANAG-4285, KG-84C encrypted (20Oct16) (AAI)
05405.0 YK01: Algerian Mil, ALG 0551 USB MIL 188-141 2G-ALE calling PY01 (26Oct16) (AAI)
05410.0 3127: Sonatrach, ALG 0647 USB MIL 188-141 2G-ALE sounding (24Oct16) (AAI)
05415.5 ---: Russian Mil (prob. AF) 0710 J3E/USB female voice comms (24Oct16) (AAI)
05420.0 IU01: Algerian Mil, ALG 0634 USB MIL 188-141 2G-ALE calling JP01 (27Oct16) (AAI)
05424.0 5B: Bosnia Herzegovina Defense 5th Infantry Brigade Tuzla, BIH 0722 USB MIL 188-141 2G-ALE handshake 2PB flwd MIL 188-110A (24Oct16) (AAI)
05453.0 FP: prob.Italian Guardia Costiera, I 0645 J3E/USB stations: WW, EA, EB, EF, radio-checks, coded msgs as ADA,ASA,ASB,ATA,ANA,ATB using NATO phonetic, prob voice-net parallel to data-net (20Oct16) (AAI)
05455.0 RD21: Algerian Mil, ALG 0557 USB MIL 188-141 2G-ALE handshake PY20 flwd by 188-110A (25Oct16) (AAI)
05500.0 5555: Unid net 0610 USB MIL 188-141 2G-ALE calling 4444 [CMD AMD][/>A2001  ] (20Oct16) (AAI)
05792.0 2212: Unid net 0614 USB MIL 188-141 2G-ALE sounding (20Oct16) (AAI)
05813.5 DO7: Polish Mil, POL 0619 USB MIL 188-141 2G-ALE calling RA2 (26Oct16) (AAI)
05813.5 DO7: Polish Mil, POL 0621 USB MIL 188-141 2G-ALE calling PT1 (26Oct16) (AAI)
05813.5 WI5: Polish Mil, POL 0619 USB MIL 188-141 2G-ALE sounding (26Oct16) (AAI)
05850.0 BU4: Roumenian Police, ROU 0633 USB MIL 188-141 2G-ALE handshake TUL flwd by 188-110A transporting STANAG-5066 HBFTP msgs (24Oct16) (AAI)
05903.0 DO7: Polish Mil, POL 0621 USB MIL 188-141 2G-ALE handshake WI5 (26Oct16) (AAI)
05903.0 DO7: Polish Mil, POL 0627 USB MIL 188-141 2G-ALE calling TE6 (26Oct16) (AAI)
06450.0 ZOCCOLA: Guardia di Finanza, I 0720 USB MIL 188-141 2G-ALE handshake CAGLIARI, voice comms using callsigns ROSTRO549 (ALE ZOCCOLA) and SIRIO60 (ALE CAGLIARI): position, heading and speed of ROSTRO549 (27Oct16) (AAI)
06510.0 Z1V: Slovackian AF Zvolen, SVK 0633 USB 188-141 2G-ALE handshake P1O Prezov flwd by 188-110A transporting Stanag-5066 HBFTP msgs (20Oct16) (AAI)
06779.0 ---: Unid 0705 USB RFSM-8000 modem with data-masking (21Oct16) (AAI)
06806.0 ---: Unid 0845 USB MIL 188-141 2G-ALE using App.B Linking Protection (27Oct16) (AAI)
06905.0 BX02: Algerian Mil, ALG 0757 USB MIL 188-141 2G-ALE calling PY01 (22Oct16) (AAI)
06905.0 HN02: Unid (Algerian Military?) 0824 USB MIL 188-141 2G-ALE handshake BZ01, no traffic (27Oct16) (AAI)
06931.0 ---: Unid 0628 USB modified STANAG-4285 waveform (21Oct16) (AAI)
07316.0 ---: Russian Nvay, RUS 0615 (cf) CIS Navy "Akula" FSK 500Bd/1000 (25Oct16) (AAI)
07535.0 CP01: Algerian Mil, ALG 0541 USB MIL 188-141 2G-ALE calling PY01 (25Oct16) (AAI)
07656.0 ---: Russian Intel, RUS 0710 USB CIS FTM-4, MFSK-4 150Bd (effective 37.5Bd) 4000Hz modem (tones at: -6, -2, +2, +6 KHz) (26Oct16) (AAI)
07745.0 TBB: Turkish Navy Ankara, TUR 0520 USB STANAG-4285 600bps/L CARBs//TBB040I(0)/TBB041I(0)/TBB043I(0)/TBB045I(0)/TBB049I(0)/TBB050I(0)// (25Oct16) (AAI)
08950.0 83401: Turkish Emergency Net, TUR 2037 USB MIL 188-141 2G-ALE sounding (22Oct16) (AAI)
09095.0 ---: Unid (prob. Ukrainian net) 0522 USB 3 of 6x100Bd/120Hz VFT system (26Oct16) (AAI)
10168.0 ---: Unide 1229 USB Arcotel MAHRS-2400 ALE bursts (25Oct16) (AAI)
11155.0 RIT: Rus Navy HQ Severomorsk, RUS 0846 CW "RAL65 DE RIT QSA?" (23Oct16) (AAI)
11155.0 RIT: Rus Navy HQ Severomorsk, RUS 0857 CW "RKN64 DE RIT RIT QSA 2 QRV K" (23Oct16) (AAI)
11429.0 ---: Russian Intel, RUS 1045 (cf) MFSK-68 (34+34) + QPSK 2400Bd 10KHz wide-band inserts (25Oct16) (AAI)
11470.0 ---: Unid (prob. Russian Navy) 1315 FSK 50Bd/500, no traffic (25Oct16) (AAI)
13215.0 201067: USAF unid asset 1113 USB MIL 188-141 2G-ALE sounding (27Oct16) (AAI)
13220.0 ---: no call 1323 USB MIL 188-141 2G-ALE calling CHARLY46 Italian AF (46th Air Brigade) (27Oct16) (AAI)
13499.0 11021: Moroccan Civil Defence, MRC 1122 USB MIL 188-141 2G-ALE sounding (27Oct16) (AAI)
13499.0 2215: Moroccan Civil Defence, MRC 1108 USB MIL 188-141 2G-ALE sounding (27Oct16) (AAI)
13499.0 2415: Moroccan Civil Defence, MRC 1109 USB MIL 188-141 2G-ALE sounding (27Oct16) (AAI)
13505.0 ---: Unid 1120 USB STANAG-4538 LSU + LDL, Harris Citadel encryption (27Oct16) (AAI)
13538.0 ---: Russian Mil, RUS 1213 USB CIS-45 OFDM HDR modem v2 BPSK 40Bd 62.5Hz (23Oct16) (AAI)
13554.0 CENTR3: MAECT Bucarest Centrala3, ROU 1047 USB MIL 188-141 2G-ALE handshake BLJ Telaviv Embassy, flwd by 188-110A transporting STANAG-5066 messages (27Oct16) (AAI)
14493.0 RGG: Russian Mil, RUS 1134 CW "RGP RGP RGP DE RGG RGG QSY 14653 QSY 14653" (21Oct16) (AAI)
14581.5 ---: Russian Navy, RUS 1330 FSK 50Bd/40, 7-bit code 4/3 (four 1 + three 0) (23Oct16) (AAI)
14968.0 XSS: DHFCS Forest Moor, G 1337 USB MIL 188-141 2G-ALE calling XDV (22Oct16) (AAI)
16000.0 6207: Unid 1213 USB MIL 188-141 2G-ALE calling 6202 (26Oct16) (AAI)
16103.0 Russian Mil, RUS 1244 USB CIS-112 OFDM modem 22.22Bd BPSK (24Oct16) (AAI)

a (possible) 3G-HF multicast transfer with MDLN protocol

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This burst-trasmision has been heard on 13505.0 KHz/USB at 1120 UTC (27 Oct). All of the burst waveforms use an 8-ary PSK serial tone modulation of an 1800 Hz carrier at 2400 symbols per second (fig. 1)

fig. 1
The analysis of the bursts say that they belong to the HF burst waveforms described in STANAG-4538 3G-HF or ARCS (Automated Radio Control System) in NATO nomenclature, specifically: after the initial BW5 FLSU burst, there are four BW3 tansmissions which transport 4 x 512 bytes of data and two zero-filled BW3 transmissions which transpot 2 x 51 bytes of data. The transfer ends with a single BW4 burst. 

fig. 2 - BW3 burst
fig. 3 - BW4 burst
BW3 and BW4 waveforms are used by LDL protocol, as defined in STANAG-4538. In a normal  LDL data transfer, the sending station and the receiving station alternate transmissions in the manner of figure 4, the sending station transmitting LDL_DATA PDUs containing payload data  packets,  and  the  receiving  station  transmitting  LDL_ACK  PDUs  each  containing  an acknowledgement  of  whether  or  not  the  data  packet  in  the  preceding  LDL_DATA  PDU  was received without error.
The LDL_EOM PDU is transmitted in the forward direction, in place of an LDL_DATA PDU, when the sending station receives an error-free LDL_ACK PDU indicating that the entire user  datagram  has  been  delivered  to  the  receiving  station  without  errors.    This PDU  is  also transmitted  using  the  BW4  waveform.    LDL_EOM  PDUs  are  distinguished  from  LDL_ACK PDUs by context: any PDU sent using BW4 in the forward direction is an LDL_EOM PDU, while any PDU sent using BW4 in the reverse direction is an LDL_ACK PDU
.

fig. 4 - 3G-HF LDL protocol transfer session
Conversely, in this recording there are no BW4 ACK bursts returned by the receiver station but only a final BW4 burst signaling the end of the data transfer,unless the BW4 ACKs were transmitted and I did not receive them:

fig. 5 - the heard 3G-HF session
The supposed lack of ACKs in figure 5 leads to think to a non-ARQ multicast transmission or a trasmission for recipients which are in EMCON (Emission Control): anyway STANAG-4538 does not provide the non-ARQ modality and the HDL/LDL protocols are for point-to-point applications only.
A possible scenario could be the use of the MDL-NACK protocol, Multicast Data Link with NAKs or MDLN. MDLN is a 3G multicast protocol with embedded retransmissions for non-EMCON users. The MDL protocol is added alongside the point-to-point 3G data link protocols HDL and LDL and shares many of the characteristics of the other 3G data link protocols (fig. 6).

fig. 6 - extended 3G-HF
In MDLN each forward transmission is followed by a pause during which receivers that were not able to decode that transmission emit a very robust pseudonoise (PN) PSK symbol sequence to request retransmission (fig. 7). All receivers share the NAK slot. (Detection of the PN NAK sequence is sufficiently robust to allow any number of NAKs to overlap during the slot.) When the sender detects a NAK, it sends additional redundancy bits. Thus MDLN, like the point-to-point ARQ protocols, sends only enough redundancy to convey the message error-free. 
In our case, the data transfer is performed using MDL-512, a robust mode that uses a stream of 512-byte BW3 bursts. All recipients have decoded the entire transmission so we do not see NACKs.

fig. 7 - MDL-NACK opeation
MDL-MDLN protocol has been introduced in "Third Generation and Wideband HF Radio Communications" and in "Military Communications Conference, 2005" by E. Koski - Harris Corporation. The presence of the Citadel pattern (fig. 8) in the decoded bistream is a strong clue and would just confirm the use of Harris equipment. The transfer contains only one encrypted datagram. Obviously, the encryption is off-line.

fig. 8 - Citadel encryption
Another similar BW3 bursts transfer has been heard on 11430.0 KHz/USB (fig. 9): unfortunately an adiacent strong OTHR emission totally drowned the signal so I could not hear the final part of the transfer. Also in this recording there are no BW4 ACK bursts returned after BW3 data bursts: a coincidence:BW4 ACK bursts sent and one more time not received?
fig. 9
 In this case the transfer convey several Citadel encrypted datagrams:

fig. 10

Unid PSK-8 2400Bd (ARQ) system

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unid, possibly ARQ, system heard and tuned using the remote Twente-SDR on 5740.0 KHz/USB for a long standing time. The waveform used by S1 S2 stations is a 1800 Hz carrier which is modulated at constant rate of 2400 symbols per second (fig. 1): QPSK is probably used for the initial preamble and PSK-8 for the data blocks (fig. 2). Each transmission, both from S1 and S2, lasts about 1660 msec.

fig. 1
fig. 2
The use of QPSK modulation is confirmed by the four accentuaded positions in the constellation diagram (fig. 3), moreover the preamble seems to be sent at higher level than the data blocks (fig. 4).

fig. 3
fig. 4
The signal has an ACF of 112.5 msec which corresponds to a period length of 810 bit or 270 PSK-8 symbols @ 2400 Baud. However, the frame length is the half of the period i.e. 135 symbols: the ACF value may be due to the lenght of the scrambler or the length of the interleaver, i.e. 810 bit. Most likely the frame consists of 32 known symbols and 103 unknown data symbols (fig. 5). 

fig. 5

https://yadi.sk/d/8sNOkDw6y4fap





An interesting comment from my friend ANgazu:
UNID PSK in last entry looks very interesting. Seems to be an hibrid modem.
Header is likely to use MSK. 32 symbols sync sequences use QPSK and are very similar to MIL-STD reinserts.



I agree, the strong PSK-4 positions in the constellation are just due to the repeated known symbols sequences.

unid 3KHz/6KHz channel waveforms in Maritime Band

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These are unidentified signals heard by me and my friend KarapuZ in the Maritime Band segments, mainly 8 and 12 MHz, during daylight. Transmissions are a mix of 3 KHz and 6 KHz wide channels (BW) and use PSK modulation, symbols rate is dependent on the bandwidth:
3 KHz BW: 2400 symbols/sec, BPSK modulation (fig. 1)
6 KHz BW: 4800 symbols/sec, BPSK and QPSK modulation (figs. 2, 3)

fig. 1
fig. 2
fig. 3
The most interesting transmission is what seems an Independent Side Band ARQ system in which the sender use the upper band to convey messages and receiver use the lower band for ACKs, both use BPSK modulation and 2400Bd symbols rate (figs. 4,5)

fig. 4
fig. 5
In order to get better quality signals, at the same time I tuned the 12 MHz band using the remote SDR at Twente University: curiously such signals were not received at the remote site. I know that this test make a poor sense but it could be a little clue about the origin of these transmissions. 




https://yadi.sk/d/DSfW8C_oyAEBd

STANAG-4538 3G-HF, HDL complete session

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3G-HF HDL transfer heard on 10627.0 KHz/USB at 1258 UTC
The High-throughput Data Link protocol (HDL), defined in STANAG-4538, is a selective repeat ARQ protocol which can only be run in a point-to-point data packet connection. HDL is most efficient when large volumes of data are to be transmitted and the channel conditions are moderately good, while LDL is best suited for small data volumes and in poor quality channel
"Data transfer by HDL begins after the stations have already established the data link connection in the traffic setup phase (using FLSU BW5 waveform). In an HDL data transfer, the sending station and the receiving station alternate transmissions in the manner depicted in figure 1; the sending station transmitting HDL_DATA PDUs containing payload data packets, and the receiving station transmitting HDL_ACK PDUs containing acknowledgments of the data packets received without errors in the preceding HDL_DATA PDU. The end of a data transfer is reached when the sending station has transmitted HDL_DATA PDUs containing all of the payload data in the delivered datagram, and the receiving station has received these data without errors and has acknowledged their successful delivery. When the sending station receives an HDL_ACK PDU indicating that the entire contents of the datagram have been delivered successfully, it sends an HDL_EOM PDU repeated as many times as possible within the duration of an HDL_DATA PDU, starting at the time at which it would have otherwise transmitted the next HDL_DATA PDU." [1]

fig. 1
As in STANAG-4538 Table 13-1, HDL protocol use the burst waveforms BW2 for data forward and BW1 for ACK and EOM/Term signal, all the burst waveforms use the basic PSK-8 modulation at 2400 baud centered at 1800hz also used in the MIL-STD 188-110A serial tone modem waveform(fig. 2) and can be identified by measuring their duration (fig. 3)

fig. 2
fig. 3
BW2 consists of 100 msec TLC section and a short (26,67 msec) preamble followed by a number of fixed-size data packets (3, 6, 12, or 24): the number of packets is negotiated before the HDL protocol starts and remains unchanged until the end of the data transfer. Each packet consists of 20 frames, each of which contains 32 unknown symbols (data) followed by 16 known symbols acting as probe (fig. 5). 
HDL protocol is packet-oriented, in contrast with LDL protocol which is byte-oriented, and it can be designated by a number as HDL<n> where n - as said above - is the negotiated  number of packets which are transmitted in one forward frame: for example, in the recorderd transfer we see HDL3-type frames.

fig. 5
Burst waveform 1 (BW1) is a general-purpose waveform used to carry short messages for many of the 3G protocols: traffic management, link maintenance, and data acknowledgments for the HDL protocol. It consists of 576 PSK-8 symbols preamble followed by 2304 PSK-8 symbols of data which are coded using 16-ary Walsh seqences (fig. 6).

fig. 6
It's worth noting that all the six burst waveforms specified by STANAG-4538 begin with a TLC/AGC guard sequence, why? Existing HF radios were generally not designed with burst waveforms in mind. For example, MIL-STD-188-141 military radios are allowed 25 ms to reach full transmit power after keying. While the transmitter radio frequency stages are ramping up, the input audio signal level is adjusted by a transmit level control (TLC) loop so that it fully modulates the transmit power. At the receiver, an automatic gain control (AGC) loop must also adjust to a new receive signal. To accommodate these characteristics of existing radios, the 3G burst waveforms just begin with a TLC section of “throwaway” 8-ary PSK symbols that are passed through the system while the transmitter’s and receiver’s level control loops stabilize.

[1] from: "Third-GenerationandWidebandHFRadioCommunications" 
 


Logs

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08002.0 KHz/USB 1518 UTC STANAG-4538 HDL+ data transfer
04926.0 KR4: Polish Military, POL 1827 USB MIL 188-141 2G-ALE calling ST8 (08Nov16) (AAI)
04926.0 KR4: Polish Military, POL 1837 USB MIL 188-141 2G-ALE calling FU7 (08Nov16) (AAI)
05316.0 9A3WD1: Croatia HF-ALE net, HRV 0932 USB MIL 188-141 2G-ALE calling 9A3DZL, prob. supporting NPRD? (03Nov16)
05316.0 K51: Croatia NPRD, HRV 0927 USB MIL 188-141 2G-ALE calling STHQ01 (03Nov16) (AAI)
05400.0 ---: Unid 1450 USB USB MIL 188-141 2G-ALE Link Protect (10Nov16) (AAI)
05424.0 FIT3: Bosnia Herzegovina Defense, BIH 0817 USB MIL 188-141 2G-ALE handshake with FI3 flwd by 188-110A transporting STANAG-5066 HBFTP msgs (03Nov16) (AAI)
05472.0 ---: Unid 0801 USB TADIRAN AutoCall MFSK-4 (10Nov16) (AAI)
05740.0 ---: Unid 0750 USB Unid PSK-8 2400Bd ARQ system, ACF = 112.5ms/810 bit, 135 symbols length frame with QPSK preamble (03Nov16) (AAI)
05785.0 PRATICA01: GdF, I 0735 USB MIL 188-141A 2G-ALE calling SAGITTARIO (28Oct16) (AAI)
05838.0 ABC7: Croatian Mil, HRV 0921 USB MIL 188-141 2G-ALE calling ABS5 (03Nov16) (AAI)
06220.0 DSM2: Unid 1818 CW "3VD6 3VD6 DE DSM2 DSM2 R 469? K", same msg for TGYH,Q2LR,8FLO,H5HF (06Nov16) (AAI)
06224.0 AA5: Israeli AF, ISR 1714 USB MIL 188-141 2G-ALE sounding (06Nov16) (AAI)
06228.0 ---: Unid 1706 USB Hagelin HC-256 voice scrambler (06Nov16) (AAI)
06310.0 BS008C1: CS/RS net 0909 USB MIL 188-141 2G-ALE calling CS004A (08Nov16) (AAI)
06316.0 ---: Unid 1750 USB RACAL/THALES Panter-H modem Frequency Hopper QPSK 2400Bd (06Nov16) (AAI)
06324.5 XSS: DHFCS Forest Moor, G 1736 USB MIL 188-141 2G-ALE sounding (06Nov16) (AAI)
06358.5 PBB: Dutch Navy Den Helder via Goeree TX, HOL 1732 (cf) FSK 75bd/850 CARBs "02A 04B 06A 08B 12A 16X 22X PBB" (06Nov16) (AAI)
06394.0 ---: Russian Military, RUS 0824 USB AT3004-D modem BPSK 120Bd (06Nov16)
06424.5 IDR: Italian Navy S.Rosa Rome, I 0855 J3E/USB daylight component, radio check with Bussola, Orale, Filone (06Nov16) (AAI)
06450.0 GENOVA: GDF, I 0915 USB MIL 188-141 2G-ALE calling GAETA (08Nov16) (AAI)
06654.0 DB5: Iraqi Border Police Region 5 Najaf, IRQ 1745 USB MIL 188-141 2G-ALE calling SHA (08Nov16) (AAI)
06715.0 CROSPR: USAF Croughton SIPR-net, G  1746 USB MIL 188-141 2G-ALE sounding (06Nov16) (AAI)
06765.0 CNP: Roumenian Police, ROU 0932 USB MIL 188-141 2G-ALE calling VAS (10Nov16) (AAI)
06767.0 ABC7: Croatian Military, HRV 0904 USB MIL 188-141 2G-ALE calling ABF2, rptd on 6909.0, 06990.0 (08Nov16) (AAI)
06772.0 LIS: Unid net 1826 USB MIL 188-141 2G-ALE sounding (11Nov16) (AAI)
06772.0 LIS: Unid net 1837 USB MIL 188-141 2G-ALE calling XGY (11Nov16) (AAI)
06783.0 ALA2: Unid net 0842 USB MIL 188-141 2G-ALE calling SLIKA2 (08Nov16) (AAI)
06795.0 381013: Turkish civil defense, TUR 1716 USB MIL 188-141 2G-ALE calling 367013 (06Nov16) (AAI)
06801.0 D20: NPRD net, HRV 0916 USB MIL 188-141 2G-ALE sounding (08Nov16) (AAI)
06805.0 2600: Unid net 0827 USB MIL 188-141 2G-ALE calling 1600 (10Nov16) (AAI)
06841.0 RCV: Russian Navy Sevastopol, UKR 1725 (cf) T600 FSK 50Bd/250 msg Sync 0x1eb41eb2952 (06Nov16) (AAI)
06870.0 PY10: Algerian Mil, ALG 0731 USB MIL 188-141 2G-ALE calling KB16 (03Nov16) (AAI)
06902.6 KXV44: US DoS station 0941 USB MIL 188-141 2G-ALE calling KXV44 (08Nov16) (AAI)
06906.0 3110: Unid net 0731 USB MIL 188-141 2G-ALE sounding (03Nov16) (AAI)
06971.0 ---: Russian Intel, RUS 1700 USB CIS FTM-4, MFSK-4 150Bd (effective 37.5Bd) 4000Hz modem (tones at: -6, -2, +2, +6 KHz) (06Nov16) (AAI)
07315.0 KF01: Algerian Military, ALG 0904 USB MIL 188-141 2G-ALE handshake ND01 flwd by MIL 188-110 App.B OFDM 39-tone modem (11Nov16)(AAI)
07575.0 WG11: Algerian Military, ALG 0750 USB MIL 188-141 2G-ALE sounding (11Nov16) (AAI)
07578.0 WG21: Algerian Military, ALG 0752 USB MIL 188-141 2G-ALE calling AT20 (11Nov16) (AAI)
07611.0 PY40: Algerian Mil, ALG 0903 USB MIL 188-141A 2G-ALE calling FQ65 (28Oct16) (AAI)
07879.5 DB1: Iraqi Border Police, IRQ 1702 USB MIL 188-141 2G-ALE calling DUH (11Nov16) (AAI)
07879.5 DB1: Iraqi Border Police, IRQ 1716 USB MIL 188-141 2G-ALE calling SUL (11Nov16) (AAI)
07950.0 BX01: Algerian Military, ALG 0756 USB MIL 188-141 2G-ALE calling PY01 (11Nov16)(AAI)
07950.0 FN01: Algerian Military, ALG 0800 USB MIL 188-141 2G-ALE calling PY01 (11Nov16)(AAI)
07950.0 WG01: Algerian Military, ALG 0755 USB MIL 188-141 2G-ALE calling AT01 (11Nov16) (AAI)
07950.0 WL01: Algerian Military, ALG 0757 USB MIL 188-141 2G-ALE calling PY01 (11Nov16)(AAI)
08000.5 HBLZDRD1: Roumanian Military, ROU 0806 USB MIL 188-141 2G-ALE calling HFJCDRD1 (11Nov16)(AAI)
08002.0 ---. Unid 1518 USB STANAG-4538 HDL+ data transfer (10Nov16) (AAI)
08015.5 ---: Russian Diplo, RUS 1519 (cf) CIS-3000 PSK-8 3000Bd serial flwd by MFSK-68 (34+34) + QPSK 2400Bd 10KHz wide-band inserts (10Nov16) (AAI)
08016.0 RIHQ02: Unid net 0749 USB MIL 188-141 2G-ALE sounding (11Nov16) (AAI)
08023.0 FQ40: Algerian Military, ALG 0817 USB MIL 188-141 2G-ALE calling AT40 (11Nov16)(AAI)
08141.0 KW01: Unid net 1300 USB MIL 188-141 2G-ALE calling IX01 (11Nov16) (AAI)
08162.0 VG02: Algerian Military, ALG 0837 USB MIL 188-141 2G-ALE calling PY01 (11Nov16)(AAI)
08500.0 ---: Russian Nvay, RUS 0615 (cf) CIS Navy "Akula" FSK 500Bd/1000 (05Nov16) (AAI)
10158.0 RIHQ02: Croatian NPRD, HRV 1024 USB MIL 188-141 2G-ALE sounding (11Nov16) (AAI)
10158.0 STHQ01: Croatian NPRD, HRV 1021 USB MIL 188-141 2G-ALE sounding (11Nov16) (AAI)
10165.0 ---: Unid 0800 USB RFSM serial modem with Data Masking, QRX 10170.0 (04Nov16) (AAI)
10190.0 BSK: Algerian AF, ALG 1300 USB MIL 188-141 2G-ALE calling CM4 (03Nov16) (AAI)
10212.0 ---: Russian Mil, RUS 0730 USB AT3004-D modem BPSK 120Bd (04Nov16)
10220.0 2151: Unid net 10:06 USB MIL 188-141 2G-ALE calling 2172 (11Nov16) (AAI)
10220.0 2151: Unid net 1401 USB MIL 188-141 2G-ALE sounding (10Nov16) (AAI)
10250.0 GHARB3: (GMRA net, LYB ?) 0926 USB MIL 188-141 2G-ALE calling HQ2 with AMD "IFBUIFSHSBIBN", flwd by CLOVER-2000 62.5Bd PSK-16 data transfer (12Nov16) (AAI)
10272.5 049112:  German Red Cross, D 0922 USB MIL 188-141 2G-ALE sounding (12Nov16) (AAI)
10275.0 3127: Sonatrach, ALG 0747 LSB MIL 188-141 2G-ALE sounding (04Nov16) (AAI)
10275.0 4042: Sonatrach, ALG 1405 LSB MIL 188-141 2G-ALE sounding (10Nov16) (AAI)
10275.0 4050: Sonatrach, ALG 1255 LSB MIL 188-141 2G-ALE sounding (03Nov16) (AAI)
10280.0 4536: Unid net 0702 USB MIL 188-141 2G-ALE calling 8536 (04Nov16)
10390.0 2405: Moroccan Civil Protection, MRC 0643 USB MIL 188-141 2G-ALE sounding (04Nov16) (AAI)
10429.0 2151: Unid net 1301 USB MIL 188-141 2G-ALE sounding (09Nov16) (AAI)
10429.0 2159: Unid net 1010 USB MIL 188-141 2G-ALE handshake with 2167 flwd by voice comms (03Nov16) (AAI)
10548.0 ---: Russian Mil, RUS 0824 USB AT3004-D modem BPSK 120Bd (04Nov16)
10590.0 CM1: Algerian Air Force Blida ALG 0825 USB MIL 188-141 2G-ALE calling 761 (07Nov16) (AAI)
10596.0 ---: Russian Air Force, RUS 1350 FSK 50Bd/500 no traffic (10Nov16) (AAI)
10627.0 ---: Unid 1258 USB 3G-HF, HDL BW2-BW1 burst waveforms (02Nov16) (AAI)
10648.0 120001: Turkish Emergency Net, TUR 0638 USB MIL 188-141 2G-ALE sounding (04Nov16) (AAI)
10675.0 ---: Russian Military, RUS 0830 USB AT3004-D modem BPSK 120Bd (07Nov16)
10805.5 002: Unid net 1426 USB MIL 188-141 2G-ALE calling 001 (USCG HC-130J #2001 Hercules aircraft?) (07Nov16) (AAI)
10830.0 NDT: US-navy Totsuka J 0642 FSK 50Bd/850 encrypted transmission (04Nov16) (AAI)
10888.0 ---: Russian Military, RUS 0830 USB AT3004-D modem BPSK 120Bd (07Nov16)
10922.0 ---: Russian Mil, RUS 0737 USB AT3004-D modem BPSK 120Bd (04Nov16)
10935.0 ---: Unid 0910 (cf) FSK 100Bd/1000 (07Nov16) (AAI)
10963.2 ---: Unid 1440 USB STANAG-4285 KG-84 encrypted message (10Nov16) (AAI)
10996.0 ---: Unid 1407 (cf) R&S ALIS 228.65Bd/200 calling address 366, followon type Morse (07Nov16) (AAI)
11020.0 BSK: Algerian Air Force Biskra ALG 0755 USB MIL 188-141 2G-ALE calling CM4 (07Nov16) (AAI)
11020.0 CM4: Algerian AF, ALG 0846 USB MIL 188-141A 2G-ALE calling ILZ (31Oct16) (AAI)
11020.0 ILZ: Algerian Air Force Illizi, ALG 0754 USB MIL 188-141 2G-ALE calling CM4 (07Nov16) (AAI)
11030.0 CM1: Algerian Air Force Blida, ALG 0743 USB MIL 188-141 2G-ALE handshake COF flwd by 188-110A transporting Citadel encrypted data (07Nov16) (AAI)
11097.0 EQB: Swedish Military, S 1527 USB MIL 188-141 2G-ALE calling EQ2 (rptd on 10974.0, 10602.0) (07Nov16) (AAI)
11097.0 EQB: Swedish Military, S 1537 USB MIL 188-141 2G-ALE calling EQ1 (rptd on 10974.0, 10602.0) (07Nov16) (AAI)
11097.0 EQB: Swedish Military, S 1545 USB MIL 188-141 2G-ALE calling MON (rptd on 10974.0, 10602.0) (07Nov16) (AAI)
11100.0 DJT: Algerian Air Force Djanet ALG 0815 USB MIL 188-141 2G-ALE calling CM4 (07Nov16) (AAI)
11111.0 STAT22: Tunisian MoI, TUN 0837 USB (cf +1700Hz) PacTOR-II 100Bd/200 DQPSK, sending email to STAT152 (07Nov16) (AAI)
11111.0 STAT23: Tunisian MoI, TUN 0816 USB (cf +1700Hz) PacTOR-II 100Bd/200 DQPSK, sending email to TUD (04Nov16) (AAI)
11130.0 C3:  Moroccan Military, MRC 0818 USB MIL 188-141 2G-ALE calling R3 (07Nov16) (AAI)
11135.0 HQ3: poss. GMRA net, LYB 0851 USB MIL 188-141A 2G-ALE calling GANOB8 (31Oct16) (AAI)
11160.0 BAL: Unid (Algerian AF or decoder error ?) 0857 USB MIL 188-141 2G-ALE sounding (07Nov16) (AAI)
11168.7 HBLZDRD1: Roumanian Military, ROU 0801 USB MIL 188-141 2G-ALE calling HFJCDRD1 (07Nov16) (AAI)
11168.7 HBLZDRzZM: Roumanian Military, ROU 0800 USB MIL 188-141 2G-ALE calling HFJCDRzZM (07Nov16) (AAI)
11181.0 5B: Bosnia Herzegovina Defense 5th Infantry Brigade Tuzla, BIH 0823 USB MIL 188-141A 2G-ALE calling AB (31Oct16) (AAI)
11198.0 ---: Unid NATO 1410 DSB Link-11 CLEW (07Nov16) (AAI)
11226.0 201067: USAF unid asset 0958 USB MIL 188-141 2G-ALE sounding (03Nov16) (AAI)
11226.0 280336: USAF unid asset 0958 USB MIL 188-141 2G-ALE sounding (03Nov16) (AAI)
11430.0 ---: Unid 1043 USB 3G-HF, (prob. MDL-NACK protocol) BW3 bursts transporting Citadel encrypted data (31Oct16) (AAI)
12379.0 ---: Unid 0930 (cf) 6KHz channel ISB ARQ system, BPSK 2400 Bd (05Nov16) (AAI)
12550.0 North Korean diplo, DPRK 1015 LSB (cf + 1500Hz) DPRK-AQ 1200Bd/1200 (09Nov16) (AAI)
13270.0 8351: Turkish Civil Defence/Emergence net, TUR 0855 USB MIL 188-141 2G-ALE sounding (09Nov16) (AAI)
13471.0 ---: Unid (maybe Chinese V22?) 1415 (cf) BPSK 62.5Bd 16-bit period (06Nov16) (AAI)
13499.0 2001: Unid net 1406 USB MIL 188-141 2G-ALE sounding (04Nov16) (AAI)


cars, chameleons, networks, and other stories (update)

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6231-net (6231.0 KHz)
I recently spotted the frequency 6231.0KHz on USB where stations connect following the same procedure as of AB-net and use STANAG-5066 HMTP protocol which is transported by a STANAG-4285 modem configured for 1200 bps and short interleaver (Figs. 1,2).  As in the 5054-net, the message transfer is not preceded by ALE or selcall phase and this supports the idea of scheduled tansmissions. 
The post related to AB-net and 5054-net (HRV MORH-u) can be read here.

Fig.1 - the HF waveform (Stanag-4285)
Fig.2 - 1776 bit period (Stanag-5066)

While the transmissions in the AB-net are scheduled on tuesday and thursady from 0830 UTC (0730, daylight savings time), transmissions on this frequency start  at 0800 UTCon monday and wednesday (most likely 0700, daylight savings time)[1].These are the heard callsigns,  listed in the call-order: 
GHU3 (net-control station)
ONI6
ZIO4
OLI7
NIK2
ULI6
VEL8
CIK5
ZIL7
Stations are contacted a first time by GHU3 for a radio-check then, in case of messages, the stations shall be contacted a second time and in the same order. Unless the initial 188-141 2G-ALE phase, the message transfer follows the schema seen here, used in the AB-net.

The HMTP headers in Fig. 4 prove that this net belongs to the HRV MORH-u network as the previous AB-net and 5054-net: same OS (Linux Open-SUSE), same STANAG-5066 application ("CroS 5066", developed by CROZ) and same attachment filename.

Fig. 4

The examination of the headers of the Data PDUs (D_PDU) gives the chance to get the STANAG-5066 addresses of the nodes in the play. The D_PDU headers can be highlighted by synchronizing the bitstream on the 16-bit Maury-Styles sequence 0xEB90 since all D_PDUs, regardless of type, begin with that same sync (it's just this sequence that causes the 1776-bit ACF of Figure 2).

Fig.5 - D_PDU headers
The S-5066 addresses obtained from the recordings belong to the 006.008.003.zzz subnet, then 5054.0 and 6321.0 KHz  are just two channels of the same subnet.
Below the updated S-5066 Addresses Table and the Network Map. 

AB-net 5838.0 KHz (...)
ALE  S-5066 Add.       E-mail Add. 
ABC7 006.008.001.039   user1@asdf.123 (ncs)
ABD1 006.008.004.166   user1@sdfg.123
ABG6 006.008.004.165   user1@dfgh.123
ABF2 006.008.006.226   user1@fghj.123
ABS5 006.008.008.215   user1@ghjk.123
ABK4 006.008.002.144   user1@jklp.123
ABH3 006.008.002.055          ?


5054/6231-net 5054.0 KHz, 6231.0 KHz
CALL S-5066 Add.       E-mail Add.
GHU3 006.008.004.165   user1@aysxd.111 (ncs)
ZIO4 006.008.003.032   user1@oli93.111
     006.008.003.033   user1@lost62.111

NIK2 006.008.003.036   user1@dres32.111
ULI6 006.008.003.037   user1@fejk8.111

VEL8 006.008.003.039   user1@huba9.111
ONI6
OLI7
CIK5
ZIL7



[1] further recordings are needed

R&S proprietary ARQ-protocol RSX.25 over GM-2100 HF modem

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transmission received on 06450.0 KHz on USB at 0753 UTC. The ending part in MIL 188-141A, which terminates the link, reveals that the user is the Italian "Guardia di Finanza - GdF", ALE addresses are CAGLIARI (Coastal Naval Station in Cagliari, the sender) and the patrol boat OLTRAMONTI (the receive peer). 
Data are sent using the HF waveform "Signal Format", a so-called Rohde & Schwarz proprietary waveform originated by the HF modem GM2100, in combination with the proprietary ARQ-protocol RSX.25. LAN/WAN interconnections are most likely managed by the "Message Handling System PostMan", this also from R&S.
RSX.25 literally stands forR&S adaptation of wired X.25 protocol to the HF radio channel, it derives from the packet protocol X.25 and cannot be used togheter with STANAG and MIL-STD HF waveforms such as S-4039, S-4285 and 199-110A;for these waveforms, radio protocols such as STANAG 5066 are available (quoting from R&S data sheets [1]).

The HF waveformGM2100 "Signal Format" exhibits the usual 1800Hz carrier with PSK-8 modulation at 2400 symbols/sec (Fig. 1)

Fig.1
Figs. 2a, 2b shows the structure of a frame with R&S Signal Format and transmitted by the HF modem GM2100. The preamble consisting of a fixed 192 symbol sequence enables the receive station to synchronize with correct timing and phase. The following data block consists of 64-symbols frames each composed of 48 unknown (data) symbols + 16 known symbols (probe). The postamble, terminating the data block, has a structure which is basically the same as that of the data frames but it contains a stop-code sequence instead of information data.
Fig.2a
Fig. 2b (from a different recording)

Most likely the length of the interleaver or the scrambler generates the 133.33msec ACF spikes, i.e. five data blocks which make960 bit or 320 symbols period (Fig.3).
 
Fig.3
The RSX.25 protocol permits all types of digital data to be transmitted, eg for a printer, digital camera, camcorder or fax unit. RSX.25 organizes the data to be transmitted in packets, which are successively transferred to the data modem. The packets contain a variable number of frames, the number per packet depending on radio-link quality and being adapted at regular intervals.
The data transmitted in a packet are distributed among the frames. The length of the frame data is variable and also depends on radio-link quality. In channels of very good quality, a frame contains 250 data bytes, in strongly disturbed channels 4 bytes. The length of the transmitted data is continually adapted to link quality

RSX.25 has a typical period of 8-bit period with recognizable patterns and is visible once removed the overhead due the Signal Format waveform (Fig. 4).

Fig.4

RSX.25 use the BZIP arvhivier so the received datacan be extracted to ASCII files. Although the "data protection" feature is used, some portions as the e-mail addresses or other headers are in clear-text and thuseasily identified (Fig. 5):as it waseasy to predict,ALE and e-mail addresses match.

Fig.5

Some useful links:
https://www.rohde-schwarz.com/fi/file/n160_email.pdf
https://www.rohde-schwarz.com/file/n155_shortwave.pdf


https://yadi.sk/d/L8ccg2Nnyq5Su

FLSU/FTM protocol + 188-110A Serial: example of 3G/2G switching

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This sample is a real-world example of 3G-HF Link SetUp protocol used in conjunction with a 2G MS 188-110 Serial waveform, it was copied and recordered on 9003.0 KHz/USB by my friend Mike Chace-Ortiz (mco) who kindly sent me the file
As visible in the "NATO HF House" in Fig. 1, STANAG-4538 is located at the two lowest layers of the OSI model. The Data Link protocols at Layer two are closely connected with the burst waveforms defined in the standard and located at Layer 1 and cannot be run with other waveforms. On the other hand, link-oriented protocols, which are also located at layer two, can be run "in conjunction" with other data link protocols, for example STANAG 5066, and with waveforms at Layer 1 of the HF House such as STANAG-4285, STANAG-4539 and MIL 188-110: in this case, STANAG 4538 establishes a sort of line-switched connection which STANAG-5066 or the waveforms make use of. For example, Former Selex Communications, now Leonardo, has implemented FLSU from STANAG-4538 together with STANAG-5066 for the Swedish Armed Forces. 
Fig.1 - NATO HF House
The sampleconsists of n-transmissions, each composed of a MIL 188-110A transfer running at 300bps, preceeded and terminated by BW5 bursts which control the link (Figs. 2,3):

Fig.2
Fig.3
More precisely, 188-110A frames transport Harris proprietary Citadel encrypted data, Fig. 4, so it's difficult to say what sits behind: S-5066 or FED-1052 (most likely the former).

Fig.4
Since the  1.033 msec length and the 50-bit payload, type "A"bursts correspond to the burst waveform 5 (BW5), as defined in STANAG-4538 (MIL 188-141C does NOT provide such waveform):
 
Fig.5

BW5 is an extended version of the BW0, it uses the same TLC, FEC, Walsh coding, and PN spreading but a longer preamble and the 50-bit payload (with increased interleaver span) make BW5 more robust than BW0. Note that the BW5 bursts that terminate each transmission, the type "C" bursts in Fig. 2, are a bit longer than the expected 1.03 msec: this is not a problem since only the first part, i.e.just 1.03msec length, contains modulated data (Fig. 6).

Fig.6
BW5 bursts are used to carry the PDUs of FLSU (Fast Link SetUp) and its closely associated FTM (Fast Traffic Management) protocol. PDUs for the two protocols are distinguished by the protocol field in the first three bits: 001 for an FLSU PDU versus 100 for an FTM PDU. 
Unfortunately, the decode attempt of the BW5 frames, either type "A" or type "C", does not show the expected values of the first 3 bits, unless in some cases (Fig. 7). Anyway, the presence of repeated patterns could indicate a certain consistency of the data. I do not know if it's due to decoder errors or perhaps a proprietary implementation of FLSU/FTM PDU to accomplish this 3G/2G switching: for sure, since the use of the proprietary Citadel encryption, they use Harris equipment and Harris had, and still has, a preminent role in the development of 3G-HF technology (Harris was the first who implemented STANAG-4538).

Fig.7



https://yadi.sk/d/GCq28TAjzSYzU

Logs

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04062.0 CM1: Unid net 2205 USB 188-141 2G-ALE calling CO1 flwd by voice call in French "Charlie Hotel respondrè"(23Nov16) (AAI)
05280.5 ALA2: Unid net 0828 USB 188-141 2G-ALE calling ALEJA2 (24Nov16) (AAI)
05280.5 ALA2: Unid net 0830 USB 188-141 2G-ALE calling EZERO2 (24Nov16) (AAI)
05302.0 ---: Unid 0815 USB Chinese mixed mode QPSK 2400Bd + MFSK-8 125Bd (24Nov16) (AAI)
05405.0 BI0: Algerian Military, ALG 0809 USB 188-141 2G-ALE calling PY0 (24Nov16) (AAI)
05405.0 JU01: Algerian Military, ALG 0811 USB 188-141 2G-ALE calling PY01 (24Nov16) (AAI)
06208.4 XLB: Unid net 0623 USB MIL 188-141 2G-ALE calling XLA (18Nov16) (AAI)
06230.0 LIS: Unid net 0723 USB MIL 188-141 2G-ALE calling WTF (17Nov16) (AAI)
06231.0 GHU3: Croatian Military, HRV 0907 USB Stanag-4285 1200bps/S transporting STANAG-5066 HMTP msg to VEL8. Other outstations callsigns: OLI7,NIK2,ULI6,CIK5,ZIL7 (14Nov16) (AAI)
06231.0 GHU3: Croatian Military, HRV 0907 USB STANAG-5066 HMTP over Stanag-4285 1200bps/S msg to IK5 (28Nov16) (AAI)
06320.0 Z1V: Slovakian AF, SVK 0752 USB MIL 188-141 2G-ALE handshake K1U Kuchyna then 188-110A transp. STANAG-5066 HBFTP msg (18Nov16) (AAI)
06324.0 ---: Unid 0831 USB Thales Systeme-3000 analog voice scrambler, also heard on 6400.0 KHz at 0938 (17Nov16) (AAI)
06342.0 ---: Russian Navy, RUS 0645 (cf) T600 FSK 50Bd/200 msg Sync 0x1414bebe952 (18Nov16) (AAI)
06450.0 CAGLIARI: Guardia di Finanza, I 0753 USB MIL 188-141 2G-ALE handshake OLTRAMONTI then R&S GM2100 HF-modem transp. proprietary ARQ-protocol RSX.25 (16Nov16) (AAI)
06522.6 ---: Unid 1047 Thales Robust Mode MFSK-8 125Bd (29Nov16) (AAI)
06562.0 S32: Moroccan Military, MRC 0800 USB MIL 188-141 2G-ALE sounding (26Nov16) (AAI)
06733.0 IDR: Italian Navy S.Rosa Roma, I 1318 J3E/USB wkg maritime patrol aircraft DAGA-03 Breguet Atlantic Br.1150 (14Nov16) (AAI)
06739.0 ---: USAF 0743 J3E/USB SKYKING message "DIABLO time ?? authentication UT" (18Nov16) (AAI)
06790.0 4200: Algerian Sonatrach, ALG 0827 USB MIL 188-141 2G-ALE sounding (18Nov16) (AAI)
06801.0 RIHQ02: Croatian NPRD, HRV 0848 USB MIL 188-141 2G-ALE sounding (25Nov16) (AAI)
06802.0 PC01: Algerian Military, ALG 1346 USB MIL 188-141 2G-ALE calling PY01 (14Nov16) (AAI)
06831.0 E5X: Global HF-net/NPRD-net, HRV 1444 USB MIL 188-141 2G-ALE sounding flwd by 188-110A 72-bit period msg (13Nov16) (AAI)
06840.0 RAPTOR: Unid net 0659 USB MIL 188-141 2G-ALE sounding (18Nov16) (AAI)
06906.0 3114: Algerian Sonatrach, ALG 0647 USB MIL 188-141 2G-ALE sounding (18Nov16) (AAI)
06915.0 PA01: Algerian Military, ALG 0908 USB MIL 188-141 2G-ALE handshake PY01 (25Nov16) (AAI)
06928.5 LC0: Italian Military, I 0950 J3E/USB asking BDA reports to TI4, TA5; relaying EE7 msg to TI4 (22Nov16) (AAI)
06938.0 HBLZDRD1: Roumanian Military, ROU 0823 USB MIL 188-141 2G-ALE handshake HFJCDRD1 flwd by MIL 188-110A Serial (28Nov16) (AAI)
06944.0 JCN: Saudi Air Force, ARS 1738 USB MIL 188-141 2G-ALE calling RFN (26Nov16) (AAI)
06944.0 JCP: Saudi Air Force, ARS 1753 USB MIL 188-141 2G-ALE sounding (26Nov16) (AAI)
06944.0 JCU: Saudi Air Force, ARS 1750 USB MIL 188-141 2G-ALE calling RFU (26Nov16) (AAI)
08090.0 2151: Unid net 0933 USB MIL 188-141 2G-ALE calling 2169 (29Nov16) (AAI)
08092.0 123456: Turkish civil defence test call, TUR 1330 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08093.5 A02: Netherlands Army, HOL 1328 USB MIL 188-141 2G-ALE calling A05 (27Nov16) (AAI)
08093.5 A06: Netherlands Army, HOL 0902 USB MIL 188-141 2G-ALE calling ANET (29Nov16) (AAI)
08093.5 A06: Netherlands Army, HOL 1323 USB MIL 188-141 2G-ALE calling A18 (27Nov16) (AAI)
08133.0 ---: Russian Intel/Diplo, RUS 1240 USB CIS MFSK-16 133.33Bd 175Hz (29Nov16) (AAI)
08150.6 ---: Algerian Military, ALG 1452 (cf) Bell-103 compatible modem FSK 300Bd/200 (27Nov16) (AAI)
08317.5 ---: Unid 1110 USB BPSK bursts, 4800Bd 6KHz bandwidth (28Nov16) (AAI)
08551.0 ---: Japanese Military, J 0710 USB Japanese MFSK-8, 2 redundant FSK-2 100Bd/300Hz (25Nov16) (AAI)
08580.0 ---: South African Navy, AFS 1705 USB Saab Grintek MHF-50 modem (27Nov16) (AAI)
08600.0 5112: Nigerian Police, NIG 1700 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08750.0 SHARK21: Unid net 1407 USB MIL 188-141 2G-ALE calling HQ1 (24Nov16) (AAI)
08750.0 SHARK25: Unid net 1403 USB MIL 188-141 2G-ALE calling HQ1 (24Nov16) (AAI)
08847.0 AA8: Israeli Air Force, ISR 1424 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08847.0 BB3: Israeli Air Force, ISR 1424 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08847.0 DD3: Israeli Air Force, ISR 1422 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08850.0 RAPTOR: KFOR NATO-MNBG-E 1154 USB MIL 188-141 2G-ALE sounding (27Nov16) (AAI)
08975.0 ---: (no call) 1415 USB MIL 188-141 2G-ALE calling Unid OVC (27Nov16) (AAI)
08975.0 UAN: Unid net 1415 USB MIL 188-141 2G-ALE calling CON (27Nov16) (AAI)
08984.5 SZ01: Unid net (Tunisian/Algerian ?) 0907 USB MIL 188-141 2G-ALE calling AC01 (29Nov16) (AAI)
09038.0 RAPTOR: NATO-MNBG-E 0813 USB MIL 188-141 2G-ALE sounding (25Nov16) (AAI)
09150.0 GANOB10: Unid net 1445 USB MIL 188-141 2G-ALE calling HQ1 (24Nov16) (AAI)
10185.0 J62: Moroccan Military, MRC 0911 USB MIL 188-141 2G-ALE sounding (26Nov16) (AAI)
10220.0 2167: Unid net 1509 USB MIL 188-141 2G-ALE calling 2157 (17Nov16) (AAI)
10245.5 A03: Netherlands Army, HOL 0828 USB MIL 188-141 2G-ALE calling A18 (26Nov16) (AAI)
10245.5 A06: Netherlands Army, HOL 0841 USB MIL 188-141 2G-ALE calling A18 (26Nov16) (AAI)
10330.0 920007: Unid net 0922 USB MIL 188-141 2G-ALE calling 920001 (26Nov16) (AAI)
10425.0 SRS: Unid net 1356 USB 188-141 2G-ALE calling XW0 (22Nov16) (AAI)
10425.0 XW0: Unid net 1354 USB 188-141 2G-ALE calling UYS (22Nov16) (AAI)
10425.0 XW0: Unid net 1357 USB 188-141 2G-ALE calling TCN (22Nov16) (AAI)
10425.0 XW0: Unid net 1359 USB 188-141 2G-ALE calling GY9 (22Nov16) (AAI)
10425.0 XW0: Unid net 1402 USB 188-141 2G-ALE calling BPF (22Nov16) (AAI)
10638.0 EK9: Greek Military, GRC 1416  USB MIL 188-141 2G-ALE handshake GEF (17Nov16) (AAI)
11162.0 ---: Russian Military, RUS 0900 USB CIS-45 OFDM HDR modem v1 BPSK 33.3Bd 62.5Hz (18Nov16) (AAI)
12115.0 RHI: Saudi Military, ARS 1414 ISB 188-141 2G-ALE calling AAI (19Nov16) (AAI)
12164.0 ---: Russian Military, RUS 1020 USB CIS-45 OFDM HDR modem v2 QPSK 40Bd 62.5Hz (18Nov16) (AAI)
12497.0 5601: Unid Iranian net, IRN 1340 USB MIL 188-141 2G-ALE sounding (19Nov16) (AAI)
13495.8 ---: Russian Mil/Diplo 0950 (cf) MFSK-16 65.6Bd 174.7Hz separation (19Nov16) (AAI)
13499.0 24191: Moroccan Civil Protection, MRC 1452 USB MIL 188-141 2G-ALE sounding (19Nov16) (AAI)
14643.0 ---: Russian Military, RUS 0838 USB CIS-112 OFDM modem 22.22Bd BPSK (18Nov16) (AAI)
16241.0 ---: Russian Intel/Diplo, RUS 1000 USB CIS MFSK-16 16.44Bd 175Hz (29Nov16) (AAI)

cars, chameleons, networks... (update 2)

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[previous posts: Part I (OS BiH) , Part II (MORH HRV) , Update 1 (MORH HRV)]                                                        
OPL-OPn net (5424.0 KHz)
I have already talked here about this QRG, where the heard ALE addresses were 5B, AB, 1PB, 1PC, 2PB, and 3PB (the so-called PB net), but in these days, at least from 1st December, in that same frequency I heard addresses as OPL, OP1, OP2, OP3, and OP4 (so the name OPL-OPn net). Transmissions start from about 0800 UTC and OPL seems to act as the net-control station. The used technology is the same than PB net, i.e. 188-110A and FED-1052 App.B for the messaging system, and 2G-ALE for the link setup, aside just three 188-110 App.B/FED-1052 App.A frames (see below).
 
Fig. 1
Same QRG and same nodes configuration mean the same source, OS BiH, and the same stations: just a "rotation" of the tactical on-air ALE addresses. I do not know if it's a monthly update or if the update was due to some other reason, further monitorings will helpin this direction.
As expected, once removed 188-110A and FED-1052 headers, I got files with ARX and TNEF extensions but this time I had more luck: since the informal nature of the messages (in the reported example, a simple list of sent/received telegrams) these were sent in clear-text. The reading of the extracted files in Figs 2,3 confirms the source and the rotation of the on-air addresses while the e-mail addresses of the network nodes remain unchanged (see Fig.5 of the Part I for what concerns 5PBR), so the old 5B, AB, 1PB, 1PC, 2PB, 3PB,... and the current OPL, OP1, OP2, OP3, OP4,... refer to the same nodes of a single radio-network belonging to OS BiH and running on 5424.0 KHz/USB.

Fig. 2
Fig. 3
Thre is anoddity in one of the recordered transmissions: the presence of three 188-110 App.B/FED-1052 App.A frames just before the link termination (Fig. 4).

Fig. 4
This is the first time, on my side, I see such modality during the e-mail exchanges monitored in this frequnecy: it's hard to say if it just belongs to this transmission or it appeared randomly from some other (unid) source. Anyway, it's worth noting that its time-position in the transmission flow is correct as well as its obsolescence is justified by the use of FED-1052.


https://yadi.sk/d/W19eZn8W32AwPg 

unid FSK 150Bd/250 with KG-84 encryption

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I copied this FSK modem on 06252.2 KHz (cf) on 7 December morning, carrying several messages with a very good signal strength here in JN52 (about 70 dB). The modem use a frequency shift of 250 Hertz and a modulation speed of  150 bps (Figs 1,2).

Fig. 1
Fig. 2
The most interesting thing is that the initial part of the messages contains the 64-bit sync header which is typical of KG-84 encryption
1111101111001110101100001011100011011010010001001100101010000001
followed by the 2 x 64 bit initialization vectors (each vector is repeated four times), as shown in Figs. 3,4:

Fig. 3
Fig. 4
The ending part is most likely a recognized EOM sequence.
The presence of KG-84 leads to think to a NATO country as source, surely - since the signal strength - the site of transmitter is very close to my antenna (center Italy), most likely in the Mediterranean area. 

 


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

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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 60 bit frame structure and 360 bit period length (Figs 4,5). The length of the period (Fig. 6), i.e. six times the frame length, is probably due to the length of the srambler sequence.

Fig. 4
Fig. 5
Fig. 6

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

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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 200Bd/400

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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

HARRIS proprietary Autolink-I (1G-ALE)

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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

PSTN V-series modem over a radio link ?

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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.





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