CIS MFSK-68 (34+34)

see: http://i56578-swl.blogspot.it/2016/12/cis-mfsk-64-3232-45bd.html

Unid OFDM 16-tone 75 Bd, 110 Hz (MS 188-110A App.A modified?)

I had this signal via Twente SDR on USB 14301.8 (cf)  on 28/06/15 (1710z) just in the well-known 20 mt reserved band, an that's a bit odd.

The waveform is an OFDM 16-tone PSK, 75 Bd and 110 Hz shift, sent in burst mode. It is very similar to the obsoleted Standard NATO MIL 188-110A Appendix A without the doppler tone @ 605 Hz and in not-continuous mode.

 

OFDM parameters

There is a Chinese variant of the MIL 188-110A 16 channels: it could be this case, but I could not find info or logs about it. The burst mode could lead to something like a selcall waveform but the ~720mS spaced "pips" looks like a TDMA.

Hope to get more info and/or more records.

A short recording can be downloaded from here:

https://www.dropbox.com/s/e27myozxfsua52v/def-websdr_recording_2015-06-28T19_13_33Z_14300.0kHz.wav?dl=0

Unid FSK-8 + PSK-2 1200 Bd (prob. AX-25)

Recordered this morning on 19304.0 USB (central frequency 19305.0) starting from 0937z until 1020z (s/off). The trasmission  heard consists of a series of short messages in PSK-2 1200 Bd (as well as some short bursts) along with 9-tones intervals. Sometimes a PSK-2 100 Bd preamble is sent. 

9-tones and PSK-2 1200 Bd insertions

PSK-2 1200 Bd, carrier ~1060 Hz

the 9 tones, top and bottom @ 7dB higher

PSK-2 100 Bd preamble

The transmission ended with a short CW/Morse message, decoded as "RFM U NIL SK 73" (more likely the '73' stands for greetings, as in HAM world).

 

The same waveform has been reported in radioscanner.ru:
http://www.radioscanner.ru/forum/index.php?action=search&loc=1&forum=21&topic=36750&page=1179863
and it is still un-identified.

Unid FSK 50/500

This signal was heard on 14568.0 (cf) around 1410z, 25 Jun. It's a sync FSK 2-carriers with shift = 500 Hz and baudrate = 50 Baud. ACF160ms with odd 2 bits stop and apparently no start bit.

SERDOLIK sync marker (idling)

24/06/15 16047.0 --- Russian Gov 0918 Serdolik sync marker

The sync marker sequence is sent alone or after a Serdolik Selcall as shown below

Serdolik Selcall and Sync Marker (courtesy of KarapuZ)

Serdolik, as several time reported in this blog, is a complex system used by Russian Gov/Diplo and designed to connect embassies and diplomatic missions. The link below is a little story of this system:
http://www.sozvezdie.su/museum/sura__posolskaya_svyaz_dlya_sssr/ 
Thanks to KarapuZ for the link and the Sedolik Selcall waveform.

WINMOR-500

18/06/15 10146.0 HB9AK Winlink Mail Server 0700  Winmor-500

The WINMOR (WINlink Message Over Radio) protocol is intended to be used for sending messages and binary data error free over a HF radio link. It is a Selective Repeat Automatic Retry reQuest (SRARQ) protocol where the Information Receiving Station (IRS) acknowledges receipt of the data to the Information Sending Station (ISS). Normally during a connection session the IRS and ISS exchange roles multiple times. The protocol is designed to handle the type conditions normally encountered in amateur radio transmission. WINMOR is not optimized for keyboarding or chat mode applications though this may be possible.

The WINMOR protocol uses basic OFDM (Orthogonal Frequency Division Multiplexing) modulation and a number of modulation modes and error correction schemes to adapt to changing channel conditions.
There is currently 2 operating bandwidths of 500 and 1600 Hz (@ 26 db below peak power output:

• 500 Hz BW 2 carriers 46.875 Baud 4FSK or 93.75 baud PSK
• 1600 Hz BW 8 carriers 46.875 Baud 4FSK or 93.75 baud PSK

Pic. 1a - WINMOR-500 data frames

Pic. 1b - 4FSK grid

I recently heard (18 June, Pic. 1) the WINMOR 500 Hz bandwidth mode around 0700z on 10146.0 KHz (center frequency). As said, the 500 Hz bandwidth mode use 3 modes PSK:

- 4PSK TCM, 8PSK TCM, 16PSK TCM  - 2 Carriers at 1406.25 Hz and 1593.75 Hz

and one 4FSK mode:

- 2 groups of 1 of 4 Carriers. (2 carriers active simultaneously)
  Group 1: 1312.5, 1358.375, 1406.25 and 1453.125 Hz
  Group 2: 1546.875, 1593.75, 1640.625 and 1687.5 Hz
 

A WINMOR frame is composed of a Pilot ("leader" of the frame) and Data. The Pilot is used to enable rapid identification of a transmission, to DSP tune the receiving station accurately, to establish symbol and frame sync and to indicate the frame type:

Data frames:
- Two carrier 8PSK (Pic. 2)
- Two carrier 4FSK (Pic. 3)  

Control frames:
- Connect ReQuest frame: 2 Car 4FSK
- Coded Control Frame: 2 Car 4FSK (Pic. 3,4,5)
- Ack: 2 Car 4FSK FEC (Pic. 4)
- ID frame: 2 Car 4FSK (Pic. 5)

Pic.2 - 16QAM data frame

 

Pic.3 - 4FSK data frame and control frames

Pic. 4 - control frame and ACK frame

Pic. 5 - control frame and ID frame

Source: http://www.arrl.org/files/file/WINMOR.pdf

Harris RF-5800 'Selective Call', MSK 2000Bd/1000

('Systeme3000-ALE' equivocation)

 

(AngazU,I56578)

We recently had the opportunity to get and study the Harris Selective Call waveform (we name it as Harris-ALE but it's not its official name!): it's an MSK modulation at 2000 Baud speed, followed by short MFSK-8 125 Baud in non-standard MS-188-141A (ALE), acf is 50 ms (100 bit). We focused on the initial 3 seconds segment in order to define modulation mode and other features in order to help to clarify the above misunderstanding (see later).

At first glance it looks like a serial-tone signal: carrier frequency 1600 Hz and OQPSK modulation at 2000 Bd speed (pic. 1). As reported in this article by Sergey Makarov (SergUA6) http://signals.radioscanner.ru/info/item281/ "it is not easy to tell apart between QPSK and MSK since they are tightly connected".

Pic. 1- Harris Selective Call and its phase-plane

By measuring the main parameters of the signal we had (pic.2):

baudrate (Br) = 2000 Bd

bandwidth (Bw) ~ 3000 Hz

shift (Sh) = 1000 Hz

Pic. 2

That said, and according to what reported here http://signals.radioscanner.ru/info/item68/ we are pretty sure that the Harris Selective Call is not an OQPSK but rather an MSK 2000/1000 waveform, 2000Baud speed and 1000Hz shifted. As it is clearly visible in pic.2, are verified those relationships that are specific to MKS signals, i.e.: Bw = 1.5 Br and Sh = Br/2 as shown in the cited article (pic.3):

Pic. 3 - MSK relationships (from radioscanner.ru)

  
Moreover, into the Harris signal, there is another clue that points to MSK. As you can see in the picture 4, there is a long state staying in one frequency, if should it be PSK, the frequency should come back to carrier and stay there till a new phase change. 

 

Pic. 4

 The shape of the eye diagram (pic. 5) also points in this direction (MSK with BT = 0.3):

Pic. 5

The Harris signal has an ACF value of 50 mSec (100 bit) and it is characterized by the presence of what looks like a signature, something like a 'business card':

  

As said, this is a safe-origin signal since it was recordered some years ago during Harris RF-5800 acceptance tests: at that time it was supposed to be standard in Falcon-II series radios. Harris equipment is wide spread in NATO countries, but this mode, although available, seems to be not much used.

With these points in mind, we asked ourselves the question that we indicated at the beginning: the so-called Thales “Systeme3000-ALE” (reported also in a post on this blog) has a waveform that is very similar to the Harris-ALE' one, also aurally they just sound in the same way. Browsing the web, there are logs by listeners reporting both the signals: altought the Thales waveform be almost 99.99% OQPSK, may be the case that these two signals could be confused each other ?

CIS-60 HDR modem 35.5 Bd, π/8-DPSK8

CIS-60 is one of the Russian OFDM HDR (High Data Rate) Modem modes,  it uses 60 data carriers and 1 pilot carrier located 3300 Hz from dial frequency, as usual in CIS HDR modem series. According to my logs, CIS-60 comes in two waveforms (I have logged both the twos):
- Baudrate 30, modulation QPSK
- Baudrate 35.5, modulation π/8-DPSK8
in both the cases the carriers are 44.5 Hz spaced and the signals spreads a 2800 Hz bandwidth. Sometimes you could hear operators chatting (in voice) followed by a waveform switch, i.e. from DPSK-4 to DPSK-8: I do not know if it's for tests purposes or for some other reason. The original signal has been resampled to 8888.8 Hz.

radioscanner.ru reports CIS-60 DPSK-8 waveform here:
http://signals.radioscanner.ru/base/signal231/ 

HFDVL modem: OFDM 73-tone (13 pilot tones) QPSK

(I-56578, ANgazu)

Total carriers: 73 Pilot carriers: 13 Data symbols per OFDM symbol: 60 Native sample rate (sps): 9600 FFT length (samples): 256

Modulation: QPSK Bit rate (bps): 3600 Bandwidth (Hz): 2737.5 Samples per OFDM symbol: 320

OFDM parameters, body segment

The most interesting feature is the way the 13 pilot tones are formed, and why - at a first look - we found only 1 pilot tone (the higher one).

We found that all the even tones have QPSK modulation (at least into the seen signals) :

 and the top tone (the 73th) is clearly a pilot one:

  

We found that in the odd tones there is a new element in absolute constellation that generates a PSK8 pattern in diff constellation. We guess this element is a scattered pilot and, for some reason we do not know, it shifts diff constellation of 45 degrees, giving the false PSK8:

Skipping symbols, we could see the 'no modulated pilot' feature for these tones. Then, according to our analysis, the 13 pilots coule be formed in the following way:

- 1 fixed pilot tone (73th);

- 12 scattered pilots which are chosen in turn from 3 different sets (each set contains 12 odd tones);

(...and we are quite positive that we have exactly identified all the tones of each set).

The pilot tones configuration changes at every OFDM symbol: we do not know the reason (perhaps to contrast propagation conditions?) and the algorithm that determines the initial configuration; possibly the BPSK preamble has these data inside, but it's just a guess. Anyway, as said above, it looks like that all the odd tones are pilots-candidate (we could say “virtual pilots”) and only 12 of them are used - in turn - to form the real pilots, while the remaining 24 + the 36 even tones are used to transport user data (60 tones).

Here is an example of a possible pilot tones scheme that assumes the configuration A as the initial configuration:

configuration A (73th tone + 12 tones of the set-A)
configuration B (73th tone + 12 tones of the set-B)
configuration C (73th tone + 12 tones of the set-C)
...and so on, restarting from configuration A 

The trailing segment of the signal just exhibits all the odd (pilots candidate) tones, some using BPSK modulation.

Two words about the speed. Official documentation say:

Total carriers 73, Pilot carriers 13, Data symbols per OFDM symbol 60, Bit rate (bps) 3600 (assuming Bit rate to be the “system” speed “on the air”). Since the 30 baud PSK-4 modulation, the system grants 30 * 2 * 60 = 3600 bps data rate.

The HFDVL modem (waveform is developed by the groups "CeTIC" from the Universidad de Las Palmas de Gran Canaria and "GAPS" from Universidad Politécnia de Madrid, other than Aeropuertos Españoles y Navegación Aérea) has been heard mostly on USB 14350.0 and 14828.5 transmitting from Spain: we think that they are conducting tests that involve transmitters in two diferent sites which exchanges data. In one of our 14828.8 KHz recordings is quite clearly visible the different quality of the signals:

Emailing the HFDVL modem manufacturer, we got a confirm about what we were thinking: "[...]Yes, there are two modems transmitting and at this moment there are not other frequencies involved in the test."

AT-3004D (CIS-12): MPSK 12-tones PSK-2, PSK-4 120 Baud

CIS-12 is a Soviet military pseudo OFDM 12-tones + 1 pilot tone waveform allowing scrambled voice or data-communication at 120 Baud rate, modulation PSK-2 or PSK-4. CIS-12 is also known as MS-5 (sometimes also as FIRE) while the modem name is AT-3004D (or its newer counterpart  AT-3104).  

http://signals.radioscanner.ru/base/signal37/

"An interesting feature of these signals is that the sub-carriers are not orthogonal, since the manipulation speed is 120 Hz and channel spacing is 200: it means that each channel is formed separately, not as in OFDM using IFFT all at once, although the OFDM technology is used. CIS-12 modems may appear in three different variants, according to the n-ary PSK modulation: 2-PSK, 4-PSK offset (doesn't turn on 180^) and 4-PSK.Channels 1-10 are for user-data while 11 and 12 for the inspection. Accordingly, the aggregate information rate is 1200 and 2400 (PSK-2 and PSK-4)."

PSK-2 waveform:

 

PSK-4  waveform:
KarapuZ sent me a sample of this mode along with his comment:

"this mode modem is less resistant to interference, it is mainly used to transmit a surface wave, or at a distance of not more than one hop. A chance to hear him in Italy is very small".