22 May 2020

unid 200Bd/800 FSK

Odd  and unid (to me) 200Bd/800 FSK spotted this morning on 5094.7 KHz (CF). ACF shows a transmission period of 15 bit: 111101011100101
Apparently, no relevant results after defferential decoding or descrambling tries.
Fig. 1
Fig. 2 - 15-bit pattern in the decoded bitstream
Note also in Fig. 3 the unwanted "spikes" during the manipulation when carrier (and carrier phase too in this case) change:

Fig. 3
All my TDoA Direction Finding runs point to the District of Poznan, Poland.

Fig. 3 - TDoA results

16 May 2020

yet another odd STANAG-4481F channel

May 16th update
Interesting tip from my friend cryptomaster (thanks) who pointed me the 13229 KHz (cf) fequency: also in this case it's a STANAG-4481F transmission with the characteristic of the 3-bit pattern (and obviously KW-46 encryption) but the source, however, is NAU Naval Radio Transmitter in Isabela  (PTR).

Therefore, contrary to what I had observed so far, such broadcasts do not come only from Niscemi (NSY) and Barford (AJE). Below the updated list of the successful frequencies and sites (all CF):

05120.5 NSY
06383.0 NSY
06732.0 AJE
07545.5 NSY
08145.0 NSY, AJE
08204.5 NSY
13229.0 NAU

May 9th
6732.0 KHz: another STANAG-4481F KW-46 secured channel that use the odd 3-bit pattern discussed here. This one is most likely from AJE (Barford St, John, UK) and // with 8204.5 KHz from NSY (Niscemi, Italy). 

Fig. 1
Fig. 2
Fig. 3

So far, it seems that only the transmissions from NSY and AJE exhibit the odd 3-bit pattern we are talking about. Below the current list of the successful frequencies which I observed (all CF):

5120.5 NSY
6383.0 NSY
6732.0 AJE (new update)
7545.5 NSY
8145.0 NSY, AJE
8204.5 NSY

In winter, my friend cryptomaster observed two more frequencies: 4723.9 and 5118.6 kHz (the latter probably NSY tuning freq.).

As said, it's to notice that most of the times the NSY frequencies are logged as "NSY Sigonella": well, NAVCOMTELSTA (U.S. NAVAL COMPUTER AND TELECOMMUNICATIONS STATION) Sicily, located in Naval Air Station  Sigonella, manages the Naval Radio Transmitter Facility Niscemi, housing LF/HF transmitters. Same story about AJE Barford St.John that probably is sometimes reported as Croughton, nearby (6 miles distant). 

13 May 2020

(slow) 19.5Bd/97Hz FSK, likely a Russian-Mil network

19.5Bd/97Hz (slow) FSK waveform spotted on 5331.0 KHz followed by opchat in Morse:
"RGJV de PZSF QSY 17542 K"

Source is probably some Russian-Mil network. Transmission consists of a repeated 126-bit sequence (Figs. 1,2).

Fig. 1
Fig. 2
 Interesting: a time shift of half bit is added after each sequence most likely for synch purposes (Fig. 3)

Fig. 3
A similar signal, except the 125 Hz shift, was also noted by my friend Cryptomaster: