NATO/Fr-Ny 4481F BRASS/MRL

Last update: September, 8th 2021

* the table below is NOT an exhaustive list of all STANAG-4481F transmissions, indeed new items are added as I identify, check and verify them (specifically the encryption).
** frequencies may change in time so it could be that some channels are no more used (for example, during spring/summer 2021 some 2000 Hz shift have been noted in some frequencies).

A necessary introduction, to not forget, concerns the use of the terms KG-84 and KW-46: well, it does not necessarily mean that those devices are physically deployed ashore or aboard. Rather than to the equipments, these names must be understood as referring to the used "algorithms", since - unless few exceptions - many of those devices are now obsolete and no longer used. Actually, the algorithms are emulated by interoperable and more compact devices such as, for example, the KIV-7M Programmable Multi-Channel Encryptor that can be used for communicating with the older KG-84/KIV-7 family of devices. So, I talk about:

- KG-84: when is detected the presence of the 64-bit frame sync
1111101111001110101100001011100011011010010001001100101010000001
followed by the 128-bit message indicator;

- KW-46: when is is detected the presence of the m-sequence generated by the polinomyal x^31 + x^3 +1  (KW-46T uses that M-sequences to synch the KW-46R receive devices).

Beyond that the list of frequencies is certainly not complete, a fact appears to emerge quite clearly: all the 50bps/850 FSK transmissions use KW-46 encryption, while not all 75bps transmissions (but the very large part of them) use KG-84 encryption.
French Navy 50Bd/850 FSK is a separate discussion: they use a 21-bit period stream consisting of frames which are delimited by two LFSR markers M1 M2 generated by the polynomials x^6+x^5+1 and x^7+x^6+1 and a logical "1" value bit.

Freq. (cf) Call Speed (bps) rem Async Encryption
2815.00 DHFCS 75 KG-84
4005.00 NAU 50 KW-46
4005.00 NSS 50 KW-46
4233.00 NPM 50 KW-46
4289.00 NPN 50 KW-46
4311.20 NAU 75 KW-46
4466.00 NKW 50 KW-46
4539.70 DHFCS 75 (4) 5N1 KG-84
4550.00 NKW 50 KW-46
4741.00 NAU 75 KG-84
4747.00 NAU 75 KG-84
4905.00 NPG 50 KW-46
4985.00 NAU 50 KW-46
4985.00 NSS 50 KW-46
4987.00 NSS 50 KW-46
5120.50 NSY 50 (1) KW-46
5340.00 NAU 75 KG-84
5716.00 NAU 50 (1) KW-46
6245.20 DHFCS 75 (4) 5N1 KG-84
6358.50 PBB 50 (3) KW-46
6358.50 NDT 50 KW-46
6372.00 AJE 75 KW-46
6383.00 NSY 50 (1) KW-46
6431.80 FUG 50 KW-46
6487.00 NSS 75 KG-84
6729.00 LBJ 75 KG-84
6732.00 AJE 50 (1) KW-46
6759.00 DHFCS 75 KG-84
6832.60 NAU 75 KG-84
6942.00 NSY 75 KG-84
6998.00 - 75 (5) KG-84
7455.00 NAU 50 KW-46
7545.50 NSY 50 (1) KG-84
7455.50 NSY 50 KW-46
7457.00 NAU 50 KW-46
7597.00 NPG 75 KG-84
7597.00 NPG 50 KW-46
8056.70 DHFCS 75 (4) 5N1 KG-84
8093.00 NKW 50 KW-46
8127.00 DHFCS 75 (4) 5N1 KG-84
8145.00 AJE 50 (1) KW-46
8145.00 NSY 50 (1) KW-46
8204.50 NSY 50 (1) KW-46
8538.00 NPN 50 KW-46
8564.00 - 50 (1) KW-46
8654.00 NPN 50 KW-46
8676.00 NPM 50 KW-46
8694.00 NPG 50 KW-46
8788.00 TDK 50 KW-46
8792.00 TDK 50 KW-46
8994.00 AJE 75 KW-46
9075.00 NPM 75 KG-84
9112.00 NPM 50 KW-46
9338.00 NPM 50 (1) KW-46
9380.00 NPN 75 KG-84
9830.00 NAU 50 KW-46
9830.00 NSS 50 KW-46
9832.00 - 50 KW-46
10153.00 NAU 50 KW-46
10155.00 NAU 50 KW-46
10265.00 NDT 75 KG-84
10272.00 DHFCS 75 (4) 5N1 KG-84
10430.00 NPG 75 KG-84
10974.00 NSY 75 KG-84
11222.00 NSS 75 (2) KG-84
11688.00 NAU 50 KW-46
11688.00 NSS 50 KW-46
11980.60 NAU 50 (1) KW-46
12015.00 NAU 50 KW-46
12015.00 NSS 50 KW-46
12120.00 NAU 75 KG-84
13229.00 NAU 50 (1) KW-46
13870.00 NPG 50 KW-46
14434.00 NPM 50 KW-46
15959.00 NSS 75 KG-84
16047.00 NPM 75 KG-84
16055.00 NDT 75 KG-84
16123.00 NAU 50 KW-46
16228.50 NPG 75 KG-84
16268.50 NPG 75 KG-84
18370.00 NPN 75 KG-84
18558.00 NPM 75 KG-84

totals
Freq/Stations speed encryption
82 50Bd 75Bd KW-46 KG-84
49
KW-46:48  KG-84:1
33
KW-46:3  KG-84:30
51 31

(1) sometimes found 50-75(!) bps FSK transmissions (anyway considered as 50 bps):read here
(2) sending continuous 63-bit sequence, considered as KG-84, read here
(3) that channel is normally used by PBB for their FAB (Frequency Allocation Broadcast)
(4) asynchronous 5N1 from DHFCS Crimond (Aberdeenshire, Scotland)
(5) isolated messages (no broadcast)

AJEUSAF, Barford St.John/Croughton UK
DHFCSUK Defence High Frequency Communications Service
FUGFrench Navy
LBJNorwegian Navy
NAUUS Navy, Isabela PR
NDTUS Navy, Totsuka
NKWUS Navy, Diego Garcia
NPGUS Navy, Dixon CA
NPMUS Navy, Lualualei HI
NPNUS Navy, Guam
NPGUS Navy, Dixon CA
NSYUS Navy, NRTF Niscemi/Sigonella
NSSUS Navy, Davidsonville MD
PBBDutch Navy, Den Helder
TDKTürk Deniz Kuvvetleri (Turkish Naval Forces)

Given that KW-46 is used to secure the fleet broadcasts and KG-84 is used to secure Point-To-Point  (PTP) circuits and multi-station nets [1], it follows that 50Bd/850 FSK is used for broadcast.
For what concerns the 75Bd/850 FSK transmissions, they consist of a continuous  flow of short/long messages; thus, since PTP and MRL transmissions are sporadic and short-lived due to their nature, 75Bd/850 FSK is used for a "some type of broadcast" for those unspecified multi-station nets. In this regards, it's to notice that some stations may operate simultaneously the two waveforms, as for example NPM Lualualei which has been heard on 9075 KHz (75Bd) and 9112 KHz (50Bd), thus serving two different scopes at the same time (Fig. 1).

Fig. 1
It's also to notice that different baud rates and encryption devices were used for GENSER (General Service) traffic and for CRITICOMM (operational intelligence) traffic, but that information is from old non-classified documents from 50 years ago.
I've not clear in mind what "multi-station net" stand for neither if they still refer to naval communications (it could also be that 75Bd just repeate the 50Bd broadcast).

[1] https://info.publicintelligence.net/NSA-NAG-16F.pdf

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