NATO/Fr-Ny 4481F BRASS/MRL

Last update: October, 10th 2023

* 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 Initialization Vectors;

- 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. See the related page at: https://i56578-swl.blogspot.com/p/french-navy-50bd850-fsk-fleet-broadcast.html

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
4529.70	DHFCS		75	(4)	5N1		KG-84
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
5189.50	-	50		(1)		KW-46
5304.00	NDT	50				KW-46
5340.00	NAU		75				KG-84
5716.00	NAU	50		(1)		KW-46
6114.00	PLA	50		(1)		KW-46
6231.35	-		75	(5)			KG-84
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
6855.00	AJE		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
8678.00	AJE		75				KG-84
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
10830.00	NDT		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
14375.00	NDT	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
16124.30	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
92	50Bd	75Bd	KW-46	KG-84
	54 KW-46:53  KG-84:1	38 KW-46:3  KG-84:35	56	36

(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)

AJE	USAF, Barford St.John/Croughton UK
DHFCS	UK Defence High Frequency Communications Service
FUG	French Navy
LBJ	Norwegian Navy
NAU	US Navy, Isabela PR
NDT	US Navy, Totsuka/Yokosuka Japan
NKW	US Navy, Diego Garcia
NPG	US Navy, Dixon CA
NPM	US Navy, Lualualei HI
NPN	US Navy, Guam
NPG	US Navy, Dixon CA
NSY	US Navy, NRTF Niscemi/Sigonella Italy
NSS	US Navy, Davidsonville MD
PBB	Dutch Navy, Den Helder
PLA	HFGCS Lajes Field, Azores
TDK	Türk 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