31 August 2015


Pic. 1 - Serdolik OFDM 35-tone
here a signal that is another variant of the Serdolik OFDM 35-tone: I had a similar waveform (40 Baud and 50 Hz channel separation) with PSK-4 modulation, this waveform shows the same values of speed and channel separation but the modulation in absolute/relative positions is BPSK (Pic. 2). Signal has been resampled at 8000 Hz. The same waveform is also reported in this discussion in radioscanner.ru forum. 

Pic.2 - OFDM parameters and modulation in channels
Moreover, phase in carriers #1-2-3 and #33-34-35 does not change in relative constellation then they are not modulated altough they could carry service informations. Looking deeper at the signal, in this case I used the software tools "baudline - signal analyzer" (http://www.baudline.com/), some channels in time change their modulation (Pic. 3) and it would take a much more in-depth analysis.

Pic. 3 - the same signal as seen in baudline

The signal was heard today (31 August) in the morning at 0750z and tuned on 16120.8 KHz on USB: the recording is available on request.

28 August 2015

CIS-20 in idle state

The main features of the waveform, as reported in radioscanner.ru, are: k = 3/5, 20 channels + 1 pilot, channel modulation pi/4 DQPSK, speed 75 Baud and channel step 120 Hz.
In this sample the modem was heard when in idle state: modulation switched to BPSK (4 positions in the absolute constellation) but same manipulation speed and channel separation (75 Baud and 120 Hz). Notice the resampling at its native frequency (7200 Hz as shown here). ACF in idle state is 200 mSec.
AT-3104D waveform (idle mode) OFDM parameters
AT-3104D waveform (idle mode) ACF
The recordered signal does not have a good quality and modulation is a bit confused, so I isolated a single channel to confirm the relative constellation (BPSK).
AT-3104D waveform (idle mode) single channel inspection
 As other characteristic, at least in this sample, is the carrier #13 that is not modulated

According to this post in radioscanner CIS-20 is a new version of CIS-12 so probably sourced from the same AT-3104D modem (or the older AT-3004D). Both the two modems were designed to have many different devices plugged into them to form the modem’s input – most often teleprinters unique to the different military services and civilian agencies that use them, and also, vocoders and speech encipherment systems, but all are transported in the same fashion – using one of these 2 waveforms.

27 August 2015

hurry up and get moving!

how to use an AT3004-D (CIS-12) modem as "beep-beep-beep" to draw the attention of the (lazy) operator at the other side of the link...


14974.0 --- Russian Mil, RUS 1315 USB CIS-45 HDR modem v2 DQPSK 40Bd (26Aug15)
04209.5 TAH Istanbul Radio, TUR 2243 Sitor FEC NAVTEKS-DENIZCILERE 564/15 (25Aug15)
14941.0 --- Unid prob. V22 1140 cf BPSK 62.5Bd (25Aug15)
12140.0 STAT21 Tunisian MOI, TUN 0853 USB MIL 188-141 ALE clg RDN152 (25Aug15)
12140.0 STAT21 Tunisian MOI, TUN 0844 USB MIL 188-141 ALE clg TUD (25Aug15)
12140.0 RDN Tunisian MOI, TUN 0840 USB MIL 188-141 ALE clg STAT24 (25Aug15)
09380.1 --- Unid 0755 cf Rohde & Schwarz ALIS 228.6Bd/170 selcall to 349 (25Aug15)
09050.0 --- Unid 0707 USB MIL 188-110 serial 2400bps (25Aug15)
09611.5 --- Unid prob. prob. V22 0617 cf QPSK 250Bd ~300Hz (25Aug15)
10724.0 --- Unid Iranian net 2120 cf Iranian-QPSK 468.75 Baud (24Aug15)
16103.0 X06 Russian Diplo, RUS 0715 USB MFSK-6 Mazielka selcall "645321" (22Aug15)

26 August 2015

CIS-45 v2 HDR modem 40 Bd π/4 DQPSK

This is another variant of the CIS-45 v2 waveform exhibiting the π/4 DQPSK manipulation in the channels and 40 symbols baudrate: this way the operating speed is increased to 3600 bps.


"ARTEMIS: is a useful aid for radio listeners: it allows to compare realtime spectra (from SDR waterfall for example) with those found in archives by comparison of the properties (such as frequency, bandwidth, modulation …) and verifying it through a sample image. A variety of filters allows you to narrow your search, facilitating the identification of unknown signals".

It's something like Wavecom Recordings but with the plus of filters to search a match for a certain signal. It's based and linked to sigidwiki, signals database is still far to be complete but continuously updated. 
Anyway, no miracles: you have to know what are you loking for.

project home page and (free) download:http://markslab.tk/project-artemis/

25 August 2015

prob. V22 Chinese number station

As reported in http://www.numbersoddities.nl/Chinese-stations.pdf "it seems that V22 station have been replaced by a digital mode(s). A so far unid mode very similar (if not equal) to PSK-63F (BPSK 62.5 Bd) used by HAMs has been noted on V22's frequencies but it cannot be decoded by HAM software neither in BPSK-63 nor in PSK-63F". 

There are no evidence or proof about the source/user which are behind these waveforms, only "rumors" as those reported in the above document. Anyway, me and Karapuz heard what is possibly the V22 station, or a "Chinese number station", running in BPSK at 62.5Bd and in DQPSK at 62.5 and 250 Bd on 9611.5, 14941.0 and 15799.0 KHz USB/cf, as sumarized in the pictures below.
All the recordings, as usual, are available on request for your analysis.

BPSK 62.5 Bd, 14941.0 KHz

DQPSK 62.5 Bd, 15799.0 KHz
DQPSK 250.0 Bd, 9609.5 KHz

23 August 2015

R.Romania Int. - Tiganesti: a DRM-B waveform

This is a DRM B-version: OFDM 206-tone (+ 1 empty place) 46.8Hz channel step, baudrate 37.5Bd and k=1/4 as reported in the radioscanner.ru page for DRM-A (bottom of the page, values of the k parameter). The official DRM System reference publication is ETSI DRM System specifications

OFDM symbol parameters as measured

A DRM trasmsission super frame (TSF) consists of three channels, or three transmission frames:
  •  FAC, Fast Access Channel: The Fast Access Channel is used by the receiver to obtain information about the OFDM signal properties and the SDC/MSC configuration
  • SDC, Service Description Channel: The SDC contains the information needed for MSC decoding, like the multiplex frame structure, as well as other additional information
  • MSC, Main Service Channel: audio and data stream
Since one DRM frame is 400 mS, the duration of a TSF is always 1.2 seconds. 

According to the ETSI DRM definitions, the OFDM carriers are divided in two groups and indicated as follow:

Some tones within the OFDM transmission frame are modulated with known fixed phases and amplitudes. These care pilot tones for channel estimation and synchronization. The positions, amplitudes and phases of these tonse are carefully chosen to optimize the performance, especially the initial synchronization duration and reliability. These tones are used by the receiver to detect the presence of the received signal and to estimate its frequency offset. They may also be used for channel estimation and various tracking processes. 
In DRM-B there are three frequency references, which are 750 Hz, 2250 Hz and 3000 Hz as referenced to the DC carrier that is not used; the tone numebers are: 16, 48 and 64 according to ETSI numbering (tones 120, 152 and 168 in SA numbering).
Looking at these pilot tones, they seem to have multiple modulation outlines that depend on the number of sent symbols:

- PSK-2 (periodicity 2)
- PSK-4 (periodicity 3)
- unmodulated (periodicity 4)
pilot tone 120 (ETSI 16)
pilot tone 152 (ETSI 48)
pilot tone 168 (ETSI 64)
The two couples of tones indicated by the ETSI numbering as -103,101 and -101,103 (1,205 and 3,207 in SA numbering) belong to the set of "gain reference tones" (those tones have a power gain of 2) and those who are close to the band lower and upper edges are over-boosted by a further power gain of 2, as it is clearly visible below. The periodicity of the gain reference pattern is 3 symbols:

Modulation is QAM-64 in even symbols:

in odd symbols modulation is QAM-64 with the evidence of outer phases (service and control) that are sent each three symbols; note that in this picture the signal has been resampled at a different frequency:

The positions of the service and control 'cells' are shown in Annex-A "Pilot reference" of the ETSI DRM document and justify the behaviors seen above.

Juts two words about the software "DREAM".
DREAM is an Open-Source Software Implementation of a DRM (Digital Radio Mondiale) Receiver under the GNU General Public License (GPL), it works both on-line and in post-production by processing wave recordings. Below some screenshots of DREAM that is struggling with same file processed by SA.
The software provides many measurements in the Chart Selector menu, including the views of the three phase constellations of DRM channels.

Power Spectral Density
MSC-SDC-FAC constellations

DREAM links:

22 August 2015


08010.0 --- Ukraine Mil, UKR 0630 Double FSK 100Bd/500 (22Aug15)
16730.0 AA1 Israeli AF, ISR 0740 USB MIL 188-141 ALE clg K36 (20Aug15)
12165.0 --- Unid NATO 1140 USB LINK-11 CLEW 75Bd traffic (19Aug15)
14631.0 X06 Russian Diplo, RUS 0840 MFSK-6 Mazielka selcall "362154" (19Aug15)
16103-0 --- Russian Mil, RUS 1520 CIS-45 HDR modem v1 33.33Bd burst + stream mode (18Aug15)
12226.0 --- Unid 1255 USB MIL 188-110 serial 2400bps/voice (18Aug15)
12464.0 RKO81 Russian Navy AO Lena, RUS 1207 CW FM13 "...99355 1T186..." (18Aug15)
12464.0 RCIG Unid Russian Navy ship, RUS 1203 CW FM13 "...99353 1T195..." (18Aug15)
17454.0 X06 Russian Diplo, RUS 1240 MFSK-6 Mazielka selcall "325614" (18Aug15)
20477.0 --- Portuguese AF 1540 USB OFDM 16-tone 75Bd + op. chat about ship sighting and position (17Aug15)
12464.0 RFH71 Rus Navy LS Novocherkassk (142), RUS 1203 CW "RCV DE RFH71 QYT4 QSA4 K" (17Aug15)

17 August 2015

TRITON-FRONTEX mission: Portuguese Units comms

STANAG-4197 16-tone data transfer
operators chat

17-Aug-2015, 1540z on 20477.0 KHz on USB
operators chat download

Data transfer on STANAG-4197 (16-tone) [3] followed by operators chat in Portoguese language, which is the most interesting part of the listening. This talk is between the main station (female operator, probably land station) and a Portuguese asset (vessel or aircraft), as I think. 
Main station operator asks to confirm the timetables of start and end contact (1337z, 1350z) and the relative positions. Well, from what I can translate, the positions are:
37°09'54'' North, 018°24'30" East (@ 1337z)
37°14' North, 17°58' East (@ 1350z) 
just in between Sicily Island (Italy) and Greece, in south Mediterranean, moving from East to Ovest.

The terms "parado na agua" (=stationary in the water) and "imigrantes" (=immigrants) are distinguishable, possibly one the of two  timetable-position pairs (the first ?) is related the immigrants ship, i.e. sighting and ship position. 
Anyway, the distance between these two points and the elapsed time leads to think of a Portuguese AF airborne. Now, given the geographical area and the translation,although partial, I just think to operational communications by Portoguese units engaged in Triton-Frontex mission: they have a Lockheed P-3C CUP+ ORION [1] (AF) and the vessel NRP Viana do Castelo [2] (Navy), as part of that mission. 
It's my guess, so maybe I could be wrong. Here the link to the chat,  hope that someone will download and translate the file so to confirm or comment this post: operators chat

15 August 2015

Rohde & Schwarz ALIS

This is the Rohde & Schwarz proprietary standard "ALIS" (Automatic Link Setup) selective call, an adaptive ALE procedure based on FSK modem and ALIS processor. 
The signal  (http://signals.radioscanner.ru/base/signal104/) has been heard today afternoon at 1620z on 12270.5 KHz on USB. The waveform is an FSK 228.6Bd/170 (normal FSK modulation, ALIS basic feature) using PRP as automatic error correction, ACF value of ~376 mS. By using the SA "scan raster" method is visible the feature called "diagonal bit" that can be used to recognize the signal.


About the ALIS version I do not know if this signal is probably an ALIS variant, as shown in the decoding below. What I can say is that the ACF value is different than the two diagrams reported in radioscanner.ru: these diagrams exhibit the values 399.3 and 494.7 mSec respectively for ALIS-1 and ALIS-2 versions whereas my diagram - as said above - exhibits a value of 376.2 mSec.

Processing the two ALIS samples provided in the above radioscanner.ru link, decoder k500 says "ALIS-2000" for version-1 and "Probable ALIS variant 50" for version-2 and these values do not match my results ("Probable ALIS variant: 40").
Below some decodings  from which you can see some some ALIS features and the called addresses.

[ Averaging over 14 bursts ]
Called address: 40
Pool size: 8
ALIS 2000: No
Ack: true
Followon type: External modem
Spectral diversity: Adaptive
Data rate: Fast
Data encryption: No (clear)
Rephase: false
Sending counter: 1
Probable ALIS variant: 40

[ Averaging over 2 bursts ]
Called address: 8488
Pool size: 8
ALIS 2000: No
Ack: true
Followon type: Morse
Spectral diversity: Adaptive
Data rate: Fast
Data encryption: No (clear)
Rephase: false
Sending counter: 1
Parity error in above information.
Probable ALIS variant: 40

More informations can be downloaded from this link: http://www.radioscanner.ru/uploader/2009/alis.zip
As usual, the recordered signal is available for your anaylsis: ask me by email o leave a comment below.

14 August 2015

CIS-60 idle

The signal, heard on August 12.08 16810.0 KHz on USB, is a variant of the CIS-60 idle, possibly for test or adjustment/calibration purposes. CIS-60 waveform is analyzed here http://signals.radioscanner.ru/base/signal231/  and here CIS-60 in this blog.
I say a "variant" since a similar test signal is also mentioned in radioscanner.ru at that same address, but in my sample, at a first glance, looking at its sonogram the 60 tones seem to be housed in what looks like a curious 40+20 (+1 pilot tone) grid: although all the tones are not modulated, the top 20 tones (41-60) appear in some way shifted with respect to the lower ones (1-40). 
After resampled the signal at 8888.88 Hz (shift * 200), from 1-40 tone to tone there is a 180º phase shift in the relative constellation, but,from tone 40 to tone 41 there is no variation (Pic. 1). As AngazU too suggests, this could point to a different phase of the top 20 tones during the initial generation of the signal. Moreover, looking at the OFDM parameters (Pic. 2), there is a different baudrate in (at least this) test mode (30Bd) with respect to the usual traffic mode (35.5Bd). BTW, a 30Bd traffic mode was also noted.
Recordings available on request.

Pic.1 - phase variation

Pic. 2 - OFDM parameters

11 August 2015


08984.0 --- Algerian Mil USB 2232 MIL 188-110A/B App.B 44.44Bd (11Aug15)
12337.0 REA4 AF HQ Moscow, RUS 2205 FSK 50Bd/1000 revs (11Aug15)
18720.0 --- Russian Mil, RUS 1202 USB CIS-45 HDR modem V1 33.33Bd (11Aug15)
17409.5 --- Uk Mil/Gov, UK 2120 USB WINDRM modified waveform OFDM 51-tone (07Aug15)
09272.5 --- Unid French Forces, F 2105 ARQ-E 184.6bd/850 idle(10Aug15)
11175.0 184 Unid 1826 USB MIL 188-141 ALE clg 272 (10Aug15)
12167.0 --- Unid 1250 USB unid MFSK-11 parallel tones, 125Bd 250Hz (10Aug15)
16021.5 99904 Egyptian MFA Cairo, EGY 0627 USB CODAN Chirp selcall to 22202 "Egyptian embassy Belgrade" (10Aug15)
14489.5 --- Unid 0610 prob. CIS-ARQ 100/2000 (10Aug15)
19252.0 --- Russian Diplo, RUS 1211 prob. SERDOLIK Selcall (09Aug15)

10 August 2015

Unid MFSK-11 waveforms


Heard today on 12167.0 KHz USB starting from 1250z, the recordings of these two signals are available on request. The upper waveform (Pic. wf1) exhibits 11 tones, step between tones 250 Hz and speed = 125 Baud x carrier quite the same as MIL 188-141 ALE. 
The second waveform in Pic. wf2, more complex, has segments in which are sent only a certain subset of tones.

It's difficult to say anything for sure about it, this signals is reported as CIS MFSK-11 here and classified as "unid" in an "old" post (October 2013) by Karapuz in radioscanner.ru. Browsing the web, only some reports of receptions and nothing else about identification and users.
Below a complete dump of a decoding of a short tramission, the first that has been heard: