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a difficult signal
Sometimes it may happens to come across signals for which - unless of know it a priori - it is difficult to correctly define the used modulation; it's the case of the so-called "semi-modes", where...
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Akula always reserves surprises...
A few days ago a friend of mine sent me some recordings of a serie of FSK bursts which had the same keying speed and shift (500Bd/1000Hz) as the "Akula" waveform but which differed due to the lack of...
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Japanese Navy fleet broadcast, a review of the "Japanese Slot Machine" (I)
Japanese Maritime Self-Defence Forces (JMSDF) HF Fleet Broadcast, also known as the "Japanese Slot Machine", heard with data payloads on 8312.50 KHz/USB using a remote KiwiSDR located in Azumino-city,...
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a STANAG-4285 autobaud waveform?
Interesting STANAG-4285 transmission heard on 14000 KHz/USB and sent me by my friend GrandBleu from radiofrecuencias.es (Figure 1) Fig. 1 - STANAG-4285 segmentsThe 35 sec segments seem a modified...
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does wideband Akula use a FBMC-SS waveform?
The idea for this post came to me while talking with my friend ANgazu (from radiofrecuencias.es) about an emerging Spread Spectrum (SS) technique that uses MultiCarrier waveforms (MC-SS).The question...
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async GFSK 300Bd/200 bursts (unid)
Some days ago my friend cryptomaster sent me an unid FSK transmission heard for several consecutive days at the frequency of 5114.0 kHz USB. Main waveform parameters are a keying speed of 300 Bd and a...
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300 bps (FSK & STANAG-4285) fleet broadcast, UK DHFCS
Fig. 1 - 300Bd fleet broadcast on 4505.0 KHz/USBUncommon 300 bps fleet broadcast heard on 4505.0 KHz/USB and using both FSK modulation (with a 850 Hz shift) and PSK modulation (STANAG-4285 300...
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MS-110D App.D (WBHF) transmissions, Collins Aerospace over-the-air testing?
Wideband transmission heard a few days ago on 19829.0 KHz (cf) around 1713Z, the recording was kindly sent to me by my friend linkz who also performed - successfully - the Direction Finding attempts...
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MS-110D App.D (WBHF) transmissions, Collins Aerospace over-the-air testing? (2)
Yet another MS-110D sample [1] transmitted from Oxford Junction (IA) site, recorded on 19825.7 KHz/USB and sent me by my friend linkz: this signal too is PSK8 modulated at the symbol rate of 2400 Bd...
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CIS-1200 SDPSK 1200Bd ("Makhovik", T-230-1A)
This transmission, along with a probably spurius emission 600 Hz above, was recorded on 13002.5 KHz (cf) thanks to the remote KiwiSDR located in Azumino-city Nagano, Japan [1].Fig. 1 - main signal and...
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unid FSK 300Bd/300 bursts
Interesting and unidentified FSK 300Bd/300 bursts heard on ~14490 KHz and sent to me by my friends ANgazu and cryptomaster (Figure 1).Fig. 1 - FSK 300Bd/300 burstsThe signals recorded by the latter (6...
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about the unid 32-bit protocol used in S-4538 + MS-110A transfers
This is the third time I have encountered these transmissions [1] and, given the good number of recordings made over a few days on the frequency 6964.5 KHz/USB, it is now possible to draw a more...
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Citadel II encryption in sync/async MS-110A transmissions (Algerian AF)
Altought it was introduced in 2004 [1], so far I had always seen the Citadel II encryption algorithm occur in 3G-ALE/STANAG-4538 contexts which use the circuit mode service [2][3]; conversely, in...
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QPSK &"SPIDER HF" MFSK8 waveforms (ROK Military)
I monitored the 8235.0 KHz/USB frequency (maritime band) since some days using some remote KiwiSDRs in Oita, Okayama (both Japan) and Daegu (South Korea) [1] recording several and very interesting QPSK...
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Chinese 4x4 modem (probably PLA Navy)
Chinese 4x4 waveform consisting of two groups of four PSK channels modulated at a rate of 75 Bd, the two groups are spaced by 450 Hz and channel separation is 300 Hz. The signal spreads about 2500 Hz...
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unid FSK 50Bd/612 bursts
Interesting and unid transmissions consisting of 50Bd/612(600?) FSK bursts heard by me and my friend cryptomaster a few days ago, respectively on 6969.10 KHz and 14353.73 KHz (both CF). The bursts have...
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256-bit IVs & 0xD1E221E1 sequence
Just a quick note to observe that bitstreams using (alleged) 256-bit Initialization Vectors (IV) encryption have the same 32-bit/4-byte sequence repeated three times. For example, in the bitstream in...
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Dutch Navy CARBs, a curious 8 times expanded 5N1.5 framing
On December 13th morning I accidentally tuned a KiwiSDR receiver on the well-known frequency of 8437.0 KHz USB, i.e. the Dutch Navy CARB channel operating in S-4481 FSK (8439.0 CF). Suddenly, about...
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T-219 "Yachta", analog voice scrambler
Thanks to my friend Mario, who recently sent me some recordings, I had the opportunity to study the Russian T-219 system, codenamed "Yachta" (Russian: ЯХТА). Yachta is a Russian analog voice scrambler...
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unid FSK 6Bd/50
No, it's not a typo: this FSK signal (kindly sent me by my friend cryptomaster) is really modulated at the speed of 6 Bd and 50Hz shift (Figs. 1,2).Fig. 1 - modulation speedFig. 2 - 50Hz shiftThe...
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unid PSK2/FSK2 combined bursts
This is a very interesting transmission heard on 14736.5 KHz/USB which consists of repetitive bursts lasting about 12.6 s and separated by an interval of 1300 ms. The most interesting aspect is that a...
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CIS FTM-4 transitions
CIS FTM-4 (FTM stands for Frequency-Time Matrix) is an unknown Russian "domestic" system, also known as CIS 4FSK 150 Bd, using MFSK4 150Bd/4000Hz modulation. The recorded transmission consists of two...
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SkyOFDM, still on air
Since some days I'm following transmissions on 14693.0 KHz/USB consisting of exchanges of messages between two nodes, as the different fading patterns in Figure 1 suggest.Fig. 1Messages are sent using...
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STANAG-4415, a NATO specific 188-110 75 bps waveform
The waveform of STANAG-4415 is the same as the 75 bps waveform of 188-110 (MS-110), but the requirements of receiver performance in STANAG-4415 are stricter than those of MS-110 (the mode is referred...
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CIS-Navy & Akula transmission
My friend Mario often monitors the frequency of 9201.0 KHz/USB in search of "Akula" signals: he mainly uses a KiwiSDR receiver located in Japan (Azumino-city, Nagano) [1] and it seems that this...
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