NATO/Fr-Ny 4481F BRASS/MRL

Last update:  26th December, 2020

The table is NOT an exhaustive list of all STANAG-4481F transmissions, new items are added as I identify, check end verify them (specifically the encryption).
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) Encryption
2815.00 75 KG-84
4005.00 NAU 50 KW-46
4005.00 NSS 50 KW-46
4233.00 NPM 50 KW-46
4289.00 50 KW-46
4311.20 NAU 75 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
5120.50 NSY 75 KW-46
5340.00 NAU 75 KG-84
6383.00 NSY 75 KW-46
6487.00 NSS 75 KG-84
6732.00 75 KW-46
6759.00 75 KG-84
6832.60 NAU 75 KG-84
6942.00 NSY 75 KG-84
7455.00 NAU 50 KW-46
7545.50 NSY 75 KG-84
7597.00 NPG 75 KG-84
8145.00 AJE 75 (1) KW-46
8145.00 NSY 75 (1) KW-46
8204.50 NSY 75 (1) KW-46
8654.00 NPN 50 KW-46
8676.00 NPM 50 KW-46
8694.00 NPG 50 KW-46
8788.00 50 KW-46
8792.00 50 KW-46
9075.00 NPM 75 KG-84
9112.00 NPM 50 KW-46
9380.00 NPN 75 KG-84
9830.00 NAU 50 KW-46
9830.00 NSS 50 KW-46
10153.00 NAU 50 KW-46
10265.00 NDT 75 KG-84
10430.00 NPG 75 KG-84
10974.00 NSY 75 KG-84
11222.00 NSS 75 KG-84 (2)
11688.00 NAU 50 KW-46
11688.00 NSS 50 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
56 25 31 32 24

AJEUSAF, Barford St.John/Croughton UK
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

(1) sometimes found 50-75(!) bps FSK transmissions (anyway considered as 75 bps): read here
(2) sending continuous 63-bit sequence, considered as KG-84, read here

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

French Navy

the so-called "Fr-21" encryption is discussed here

Freq. (cf)SpeedEncryption
2065.8050bpsFr-21
6367.3050bpsFr-21
6431.7050bpsFr-21
8518.8050bpsFr-21
8566.8050bpsFr-21
13419.8050bpsFr-21

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