Howard Fuhs
Howard Fuhs
Howard Fuhs
IT-Sicherheitsberater
IT-Sicherheitsberater
IT-Sicherheitsberater

A Short Primer on Mil Sat Coms

Copyright (C) 08/2003 by Howard Fuhs

Content 
Abstract
Mil Standards
Channel Lists
NATO IV Satellites
UHF Follow-On (UFO)
Milstar
Leasat
Fltsatcom Satellites
Receiving Tips
Equipment Tips
Further Readings


Abstract

This short primer on Military Satellite Communications below 500MHz is intented to give the monitoring hobbyist some insight into this specific section of the hobby and was written for the WUN Newsletter.

Especially the Military Satellite Communications below 500MHz are an easy target for the beginner to enter the wide field of satellite communications as the frequency range can be covered with simple antennas and a wide variety of low cost receivers.

Basically the Military Satellite Communication below 500MHz is thought to provide tactical communication possibilities to military units, from the single soldier up to warships, planes and ground vehicles, without the usage of large (dish)antennas and with small and easily transportable (manpack) transmitters with low power output. Furthermore it was important for the whole system design, that the antennas in use in the field must not be positioned very accurate towards the satellite, but can be pointed in the estimate direction of the satellite and still provide sufficient signal strength for communication.

Military Standards

The military satellite communication is defined in standards. The standards in question are an absolute must read for everybody interested in this sector. A lot of wrong information for the hobbyist compiled by hobbyists are available on the internet simply because nobody read the military specifications.

The standards to read are:

MILITARY STANDARD 188-181
INTEROPERABILITY STANDARD FOR DEDICATED 5-kHz and 25-kHz UHF SATELLITE COMMUNICATIONS CHANNELS

MILITARY STANDARD 188-182
INTEROPERABILITY STANDARD FOR 5-kHz UHF DAMA TERMINAL WAVEFORM

MILITARY STANDARD 188-183
INTEROPERABILITY STANDARD FOR 25-kHz UHF TDMA/DAMA TERMINAL WAVEFORM

These standards are available as PDF files on the internet. Use Google or look here.

Channel Lists

The following channel- and frequency-lists are excerpts from the original MIL-STD-188-181 document.

It may be noted that LEASAT and MARISAT are no longer in use. Nonetheless the frequency channels are part of the 188-181 standard and are published below.

MIL-STD-188-181
APPENDIX D

FREQUENCY PLANS

LEASAT receive and transmit frequencies.

Channel Plan	Downlink	Uplink		Nominal
             	Frequency 	Frequency 	Bandwidth
             	(MHz)     	(MHz)     	(kHz)

1 	W 	250.35 		SHF * 		25
	X 	250.45 		SHF * 		25
	Y 	250.55 		SHF * 		25
	Z 	250.65 		SHF * 		25

2 	W 	263.80 		297.40 		500
	X 	260.60 		294.20 		500
	Y 	261.70 		295.30 		500
	Z 	262.30 		295.90 		500

3 	W 	251.85 		292.85 		25
	X 	251.95 		292.95 		25
	Y 	252.05 		293.05 		25
	Z 	252.15 		293.15 		25

4 	W 	253.55 		294.55 		25
	X 	253.65 		294.65 		25
	Y 	253.75 		294.75 		25
	Z 	253.85 		294.85 		25

5 	W 	255.25 		296.25 		25
	X 	255.35 		296.35 		25
	Y 	255.45 		296.45 		25
	Z 	255.55 		296.55 		25

6 	W 	256.85 		297.85 		25
	X 	256.95 		297.95 		25
	Y 	257.05 		298.05 		25
	Z 	257.15 		298.15 		25

7 	W 	258.35 		299.35 		25
	X 	258.45 		299.45 		25
	Y 	258.55 		299.55 		25
	Z 	258.65 		299.65 		25

8 	W 	265.25 		306.25 		25
	X 	265.35 		306.35 		25
	Y 	265.45 		306.45 		25
	Z 	265.55 		306.55 		25

9 	W 	243.855 	316.955 	5
	X 	243.955 	317.055 	5
	Y 	244.055 	317.155 	5
	Z 	244.155 	317.255 	5

10 	W 	243.860 	316.960 	5
	X 	243.960 	317.060 	5
	Y 	244.060 	317.160 	5
	Z 	244.160 	317.260 	5

11 	W 	243.875 	316.975 	5
	X 	243.975 	317.075 	5
	Y 	244.075 	317.175 	5
	Z 	244.175 	317.275 	5

12 	W 	243.900 	317.000 	5
	X 	244.000 	317.100 	5
	Y 	244.100 	317.200 	5
	Z 	244.200 	317.300 	5

13 	W 	243.910 	317.010 	5
	X 	244.010 	317.110 	5
	Y 	244.110 	317.210 	5
	Z 	244.210 	317.310 	5

* Uplink frequency is super high frequency from 7.9 to 8.4 GHz on channel 1.

MIL-STD-188-181

FLTSATCOM receive and transmit frequencies.

Channel	Plan	Downlink	Uplink		Nominal
		Frequency 	Frequency 	Bandwidth
		(MHz) 		(MHz) 		(kHz)

1 	A 	250.45 		SHF * 		25
	B 	250.55 		SHF * 		25
	C 	250.65 		SHF * 		25

2 	A 	251.95 		292.95 		25
	B 	252.05 		293.05 		25
	C 	252.15 		293.15 		25

3 	A 	253.65 		294.65 		25
	B 	253.75 		294.75 		25
	C 	253.85 		294.85 		25

4 	A 	255.35 		296.35 		25
	B 	255.45 		296.45 		25
	C 	255.55 		296.55 		25

5 	A 	256.95 		297.95 		25
	B 	257.05 		298.05 		25
	C 	257.15 		298.15 		25

6 	A 	258.45 		299.45 		25
	B 	258.55 		299.55 		25
	C 	258.65 		299.65 		25

7 	A 	265.35 		306.35 		25
	B 	265.45 		306.45 		25
	C 	265.55 		306.55 		25

8 	A 	266.85 		307.85 		25
	B 	266.95 		307.95 		25
	C 	267.05 		308.05 		25

9 	A 	268.25 		309.25 		25
	B 	268.35 		309.35 		25
	C 	268.45 		309.45 		25

10 	A 	269.75 		310.75 		25
	B 	269.85 		310.85 		25
	C 	269.95 		310.95 		25

11 	A 	243.945 	317.045 	5
	B 	244.045 	317.145 	5
	C 	244.145 	317.245 	5

12 	A 	243.955 	317.055 	5
	B 	244.055 	317.155 	5
	C 	244.155 	317.255 	5

13 	A 	243.960 	317.060 	5
	B 	244.060 	317.160 	5
	C 	244.160 	317.260 	5

14 	A 	243.965 	317.065 	5
	B 	244.065 	317.165 	5
	C 	244.165 	317.265 	5

15 	A 	243.970 	317.070 	5
	B 	244.070 	317.170 	5
	C 	244.170 	317.270 	5

16 	A 	243.975 	317.075 	5
	B 	244.075 	317.175 	5
	C 	244.175 	317.275 	5

17 	A 	243.980 	317.080 	5
	B 	244.080 	317.180 	5
	C 	244.180 	317.280 	5

18 	A 	243.985 	317.085 	5
	B 	244.085 	317.185 	5
	C 	244.185 	317.285 	5

19 	A 	243.990 	317.090 	5
	B 	244.090 	317.190 	5
	C 	244.190 	317.290 	5

20 	A 	243.995 	317.095 	5
	B 	244.095 	317.195 	5
	C 	244.195 	317.295 	5

21 	A 	244.000 	317.100 	5
	B 	244.100 	317.200 	5
	C 	244.200 	317.300 	5

22 	A 	244.010 	317.110 	5
	B 	244.110 	317.210 	5
	C 	244.210 	317.310 	5

23 	A 	260.600 	294.200 	500
	B 	261.700 	295.300 	500
	C 	262.300 	295.900 	500

* Uplink frequency is super high frequency from 7.9 to 8.4 GHz on channel 1.

MARISAT (Gapfiller) receive and transmit frequencies.

Channel	Plan	Frequency	Frequency	Bandwidth
		Downlink 	Uplink 		Nominal
		(MHz) 		(MHz) 		(kHz)

A 		254.150 	307.750 	25
B 		257.550 	311.150 	25
C 						500
	1 	248.850 	302.450 	25*
	2 	248.875 	302.475 	25*
	3 	248.900 	302.500 	25*
	4 	248.925 	302.525 	25*
	5 	248.950 	302.550 	25*
	6 	248.975 	302.575 	25*
	7 	249.000 	302.600 	25*
	8 	249.025 	302.625 	25*
	9 	249.050 	302.650 	25*
	10 	249.075 	302.675 	25*
	11 	249.100 	302.700 	25*
	12 	249.125 	302.725 	25*
	13 	249.150 	302.750 	25*
	14 	249.175 	302.775 	25*
	15 	249.200 	302.800 	25*
	16 	249.225 	302.825 	25*
	17 	249.250 	302.850 	25*
	18 	249.275 	302.875 	25*
	19 	249.300 	302.900 	25*
	20 	249.325 	302.925 	25*

* In operation, communications on the 500-kHz wideband channel (Channel C) is accomplished using frequency-division multiple access (FDMA). The channel is divided into 25-kHz subchannels with transmission data rates varying between 75 and 16000 bps.

UHF follow-on receive and transmit frequencies.

Channel	Plan	Downlink 	Uplink 		Nominal
		Frequency	Frequency	Bandwidth
		(MHz) 		(MHz) 		(kHz)

1 	N 	250.350 	SHF *		25
	O 	250.450 	SHF *
	P 	250.550 	SHF *
	Q 	250.650 	SHF *
	N' 	250.400 	SHF *
	O' 	250.500 	SHF *
	P' 	250.600 	SHF *
	Q' 	250.700 	SHF *

2 	N 	251.850 	292.850 	25
	O 	251.950 	292.950
	P 	252.050 	293.050
	Q 	252.150 	293.150

3 	N 	253.550 	294.550 	25
	O 	253.650 	294.650
	P 	253.750 	294.750
	Q 	253.850 	294.850

4 	N 	255.250 	296.250 	25
	O 	255.350 	296.350
	P 	255.450 	296.450
	Q 	255.550 	296.550

5 	N 	256.850 	297.850 	25
	O 	256.950 	297.950
	P 	257.050 	298.050
	Q 	257.150 	298.150

6 	N 	258.350 	299.350 	25
	O 	258.450 	299.450
	P 	258.550 	299.550
	Q 	258.650 	299.650

7 	N 	265.250 	306.250 	25
	O 	265.350 	306.350
	P 	265.450 	306.450
	Q 	265.550 	306.550

8 	N 	266.750 	307.750 	25
	O 	266.850 	307.850
	P 	266.950 	307.950
	Q 	267.050 	308.050

9 	N 	268.150 	309.150 	25
	O 	268.250 	309.250
	P 	268.350 	309.350
	Q 	268.450 	309.450

10 	N 	269.650 	310.650 	25
	O 	269.750 	310.750
	P 	269.850 	310.850
	Q 	269.950 	310.950

11 	N 	260.375 	293.975 	25
	O 	260.575 	294.175
	P 	260.425 	294.025
	Q 	260.625 	294.225

12 	N 	260.475 	294.075 	25
	O 	260.675 	294.275
	P 	260.525 	294.125
	Q 	260.725 	294.325

13 	N 	261.575 	295.175 	25
	O 	262.075 	295.675
	P 	261.625 	295.225
	Q 	262.125 	295.725

14 	N 	261.675 	295.275 	25
	O 	262.175 	295.775
	P 	261.725 	295.325
	Q 	262.225 	295.825

15 	N 	261.775 	295.375 	25
	O 	262.275 	295.875
	P 	261.825 	295.425
	Q 	262.325 	295.925

16 	N 	261.875 	295.475 	25
	O 	262.375 	295.975
	P 	261.925 	295.525
	Q 	262.425 	296.025

17 	N 	263.575 	297.175 	25
	O 	263.775 	297.375
	P 	263.625 	297.225
	Q 	263.825 	297.425

18 	N 	263.675 	297.275 	25
	O 	263.875 	297.475
	P 	263.725 	297.325
	Q 	263.925 	297.525

19 	N 	243.915 	317.015 	5
	O 	243.995 	317.095
	P 	244.075 	317.175
	Q 	244.155 	317.255

20 	N 	243.925 	317.025 	5
	O 	244.005 	317.105
	P 	244.085 	317.185
	Q 	244.165 	317.265

21 	N 	243.935 	317.035 	5
	O 	244.015 	317.115
	P 	244.095 	317.195
	Q 	244.175 	317.275

22 	N 	243.945 	317.045 	5
	O 	244.025 	317.125
	P 	244.105 	317.205
	Q 	244.185 	317.285

23 	N 	243.955 	317.055 	5
	O 	244.035 	317.135
	P 	244.115 	317.215
	Q 	244.195 	317.295

24 	N 	243.965 	317.065 	5
	O 	244.045 	317.145
	P 	244.125 	317.225
	Q 	244.205 	317.305

25 	N 	243.975 	317.075 	5
	O 	244.055 	317.155
	P 	244.135 	317.235
	Q 	244.215 	317.315

26 	N 	243.985 	317.085 	5
	O 	244.065 	317.165
	P 	244.145 	317.245
	Q 	244.225 	317.325

27 	N 	248.845 	302.445 	5
	O 	248.975 	302.575
	P 	249.105 	302.705
	Q 	249.235 	302.835

28 	N 	248.855 	302.455 	5
	O 	248.985 	302.585
	P 	249.115 	302.715
	Q 	249.245 	302.845

29 	N 	248.865 	302.465 	5
	O 	248.995 	302.595
	P 	249.125 	302.725
	Q 	249.255 	302.855

30 	N 	248.875 	302.475 	5
	O 	249.005 	302.605
	P 	249.135 	302.735
	Q 	249.265 	302.865

31 	N 	248.885 	302.485 	5
	O 	249.015 	302.615
	P 	249.145 	302.745
	Q 	249.275 	302.875

32 	N 	248.895 	302.495 	5
	O 	249.025 	302.625
	P 	249.155 	302.755
	Q 	249.285 	302.885

33 	N 	248.905 	302.505 	5
	O 	249.035 	302.635
	P 	249.165 	302.765
	Q 	249.295 	302.895

34 	N 	248.915 	302.515 	5
	O 	249.045 	302.645
	P 	249.175 	302.775
	Q 	249.305 	302.905

35 	N 	248.925 	302.525 	5
	O 	249.055 	302.655
	P 	249.185 	302.785
	Q 	249.315 	302.915

36 	N 	248.935 	302.535 	5
	O 	249.065 	302.665
	P 	249.195 	302.795
	Q 	249.325 	302.925

37 	N 	248.945 	302.545 	5
	O 	249.075 	302.675
	P 	249.205 	302.805
	Q 	249.335 	302.935

38 	N 	248.955 	302.555 	5
	O 	249.085 	302.685
	P 	249.215 	302.815
	Q 	249.345 	302.945

39 	N 	248.965 	302.565 	5
	O 	249.095 	302.695
	P 	249.225 	302.825
	Q 	249.355 	302.955

* Uplink frequency is super high frequency from 7.9 to 8.4 GHz on channel 1.

After this extensive list of channels and frequencies I want to provide a brief overlook of the military satellite systems currently in use. These list is far from being complete as it is quite difficult to find proper information about military satellites. WUN readers are invited to provide me further information and comments which I will gladly compile to another paper.

NATO IV Satellites

The NATO IV satellites are designed to meet NATO's requirements for integration of the SATCOM element into the NATO Integrated Communication System (NICS).

NATO first became involved in satellite communications in the 1960s. In the mid-1980s NATO decided to replace its third generation system with a new series of satellites based on the UK-built Skynet 4. As a prime contractor British Aerospace Space Systems (now part of Matra Marconi Space) was appointed in 1987.

The NATO IV satellite is of a modular design and comprises a service module and a communications module. Both modules are powered by two solar arrays which rotate about their longitudinal axis to face and follow the sun.

The satellite has a launch mass of 1430 kg and a dry mass of 731 kg.

The communication module comprises three SHF transponders, each of 40W power, providing bandwidths from 60MHz to 135MHz and two 25W UHF transponderseach one serving a channel of 25kHz bandwidth. SHF antennas provide footprints from spot to full cover. The UHF antenna is a earth-cover helix.

NATO IVA was launched 07. January 1991 and NATO IVB was launched 07. December 1993.

(Jane's Military Communication, 19th Edition, 1998-99)

UHF Follow-On (UFO) Communication Satellite

The UHF Follow-On (UFO) Communication Satellites began replacing FLTSATCOM and LEASAT satellites in 1993. As the UFO satellites are compatible with FLTSATCOM and LEASAT existing ground terminals remain usable.

The satellites weigh around 1170 kg with the UHF payload and 1350 kg with the additional EHF package.

UFO satellites have 11 UHF amplifiers and 39 UHF channels with a total of 555kHz bandwidth. 21 narrowband channels at 5kHz each, 17 relay channels at 25kHz.

(Jane's Military Communication, 19th Edition, 1998-99)

Milstar Satellite Communication System

This satellite shall just be mentioned as it containes according to Jane's Military Communication only EHF packages which is outside the scope of this column.

Leasat Communication Satellite

Leasat satellites (5 in total) are 4,26m in diameter and 6,17m high with its UHF and omnidirectional antennas deployed. The satellite weigh was 1388 kg. Leasat satellites were built by Hughes Space and Communications Company and were designed exclusively for launch on NASA's Space Shuttle.

Two large helical UHF antennas were used to provide communication service in the 240 to 400 Mhz band. The main communications capability was provided by 12 UHF repeaters.

In early 1997 the Leasat satellites were retired.

(Jane's Military Communication, 19th Edition, 1998-99)

FLTSATCOM

The Fleet Satellite Communications System was initiated 1971 by the US Navy to provide tactical multichannel UHF communication. It is also used by US Air Force bombers and launch control centres, all airborne command posts, and some US Army nuclear capable force elements.

The FLTSATCOM System has 23 channels in the 244 to 400MHz range (for details see the Military Standards section), wide band channels for Navy relay communications, narrow band channels as part of the AFSATCOM system and one 500kHz wideband channel used by the National Command Authorities and one 25kHz channel for fleet broadcast.

Each of the satellites weighs 912 kg with approx. 5kW radiated power.

(Jane's Military Communication, 19th Edition, 1998-99)

Receiving Tips

As most of the scanners are covering the frequency range between 200 - 400 MHz it should be no problem to enter the field of military satellite communications. Depending on what kind of antenna you are using the signals can be weak, so it's a good idea to do the first tune over the satellite communication band without any squelch in use. For the people using good antennas (maybe together with an amplifier) and a high quality scanner (like an AOR AR5000) its quite easy to detect a lot of signals with squelch in use. As soon as you are receiving a signal you can try to adjust the squelch to a proper threshold.

When it comes to the antenna it becomes a little bit more complicated. As you will in most cases only succeed with a directional antenna you should have of course clear sight towards the satellite. There are enough satellite tracking programs on the Internet freely available (e.g. STS Orbit Plus from David Ransom; http://www.dransom.com) to show you the exact position of a satellite regarding to your specific location on the globe.

Listening to a signal and you are not quite sure whether it is a sat signal or not? It is always a good idea to have a second receiver connected to an omnidirectional antenna at hand. This gives you the opportunity to differentiate satcom signals from local signals. If only the receiver with a directional antenna pointed towards a satellite position can hear the signal you can be quite sure to listen to satcomms. If your second receiver also gets the signal it's very likely not from a satellite.

Equipment tips

There is an old saying that an antenna which is still standing after a storm was just not large enough. Similar goes for the equipment of a monitoring post. You simply can't get enough. Some people really interested in doing military satellite communication monitoring are always on the look for professional equipment. And what kind of equipment can be more professional than phased out military equipment? This can be found for example at Helmut Singer Elektronik (http://www.helmut-singer.de/) and of course at Ebay. Phased out military sat comm equipment can also be bought quite cheaply on HAM fests as well as direct from the military disposal units for surplus material. Especially the sat comm equipment is often given away for a price per kilo. The reason is that most people and companies which are buying surplus material from the government are not looking for electronic gadgets and gizmos but more for standard personal equipment which can be easily sold in shops. Thus the circle of interested persons is usually quite small.

From my own personal experience I can only recommend to look out for surplus material for the low price and the high quality.

Identifying military communication equipment is easier today than one might think. The publishing house Jane's Information Group (http://www.janes.com/) is issuing once a year "Jane's Military Communication" which is a book (800+ pages A4) listing the military communication equipment actually in use worldwide. This book does cover all aspects of military communication and should be part of every monitoring shack. The backdrop is the price of the actual edition (beyond 500.-USD) but even these books can be bought over surplus channels or at stock clearings for 50.- Euro if they are two years old or older.

Antennas

As the standard rubber duck antenna will not work you will need a directional antenna to catch the signals. Not a perfect solution but an idea to start with is a channel 12 tv antenna which originally covers 224MHz up to 230MHz. A tv antenna is cheap to buy and is working also quite well between 240 - 260MHz.

Also good results can be achieved with a LogPer antenna (200 - 900MHz or 100 - 1300MHz). Such an antenna can be found for approx. 80.-Euro at Ham fests. This antenna is about 1,70m long and relatively easy to handle. The advantage of this antenna is that it covers a wide range of frequencies and can also be used for other monitoring purposes.

For best results with the least signal losses it is recommended to use helical antennas. These antennas can be bought from HAM suppliers but unfortunately they are quite expensive and usually only for HAM frequencies available. Another possibility is to use homebrew helical antennas for the specific military satellite communication frequency area.

Always a good idea is to employ a signal amplifier at the antenna. This amplifier allows to boost weak signals and compensate signal loss through long antenna coax cable. Unfortunately these broadband amplifieres a quite expensive, but there are enough tips on the Internet available for people who like homebrew equipment. Especially when suboptimal antennas are used it is recommended to use a signal amplifier.

Further Readings

In times where everybody can search internationally for books in databases and online shops like Amazon, it shouldn't be the big problem to find proper readings about satellite communication systems. Nonetheless I want to give some hints about books you should read.

As already mentioned before Jane's Military Communication should belong into every monitoring shack. Another interesting Jane`s publication is Jane's Radar and Electronic Warfare Systems which contains also a lot of satellite equipment.

Artech House Publishers is a very good source for satellite communication books as this publisher is speciallized in books about professional communication systems (www.artechhouse.com). One of the books I would like to recommend is Satellite Communication Fundamentals from Artech House Publishers. The book gives a detailed in depth insight into all details of satellite communications including the neccessary physical basics of satellite technology together with the mathematical models and formulas.

Also worth to mention are

I hope this paper provided some usefull information for the hobbyist when it comes to military satellite communications below 500MHz. I invite your suggestions for revising or extending this paper. I plan to review and revise this paper as the need arises.


Copyright (C) 08/2003 by Howard Fuhs

 

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Thema 01
Hier finden Sie Information über Dinge, von denen wir jetzt noch nichts verraten wollen.
Premium Content
Restricted area. Paying customers only.
News
Company News and Press Informations.
Service
Protect your Assets with our Security Services.
Products
24-hour clocks according to ISO 8601 developed for usage in business, technical and military 24/7 environments.
Lectures
Informations about the worldwide Lecures and Seminars of Howard Fuhs.
Publications
Articles and Manuscripts of Howard Fuhs covering the topic of IT-Security.
Digital Publishing
Publications of Howard Fuhs on CD-ROM.
DEDeutsche Seiten
Hier finden Sie unsere deutschsprachigen Seiten.
Follow this link to our German pages.
      E-Mail
Contact us
via E-Mail
  info@fuhs.de
    Realisation
EDV-Beratung
Frank Ziemann
www.fz-net.com
Content  
Content
Hot Sites
Trade Terms  and Conditions
Hot Sites
Hot Sites (11/1998)
Trade Terms and ...
Trade Terms and Conditions - and Internet Access (05/1998)
Thema C
--not used--
Thema D
--not used--
Thema E
--not used--
Thema F
--not used--