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How to listen UFOs

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make our eyes catch to read 'em. Here are the post:

Since the late 1990's rumours have abounded that it was possible to hack into American military satellites and use them for wide area communication. The satellites, originally the 'FleetSatCom' newtork (often abbreviated to FLTSATCOM) use basic FM modulation and have uplinks in the area of 300 MHz and downlinks in the area of 260 MHz. Stories went that tuning in to the downlinks it was possible to hear illegal pirates, from Brazil in particular, who were usurping these US military satellites to use for wide-area communications. It was also said that 'Smile 93.9 FM' (rumoured to be from Manila) was using one of the channels as a studio to transmitter link and could often be heard on the downlink frequency of 269.950 MHz.

This seemed a little far fetched and unbelievable: How could one of the world's most super-sophisticated armed forces allow their multi-million dollar military hardware be taken control of by such an unsophisticated enemy armed with nothing more than a simple UHF FM transmitter? Using a simple VHF/UHF receiver and a bog standard roof mounted VHF/UHF antenna, I set out to try and debunk the myth.

Within seconds I was listening to a conversation between two likely sounding chaps on a frequency of 255.550 MHz. Next I stumbled across more voice traffic (definitely in Portuguese, the language spoken in Brazil) on 258.650 MHz. And before long I found more voice traffic on 253.850 MHz. Intrigued that this long reported phenomena was still in evidence I did a bit of digging on the internet to find out more.

The original FleetSatCom satellites which were launched in the late 1970's and early 1980's are no longer operational. They were initially replaced by satellites known as Leased Satellites (Leasat) which have also since been replaced by the UHF Follow-On series of satellites, ironically acronymised as UFO. The UFO satellites continue to provide the same communications capabilities as the earlier ones but with somewhat higher transmitter powers, making reception of them fairly straightforward.

A bit more digging uncovered military standard MIL-STD-188-181A which describes the interface specification for the satellites (i.e. the technical requirements for equipment used to access them) and in it we find a list of the uplink and downlink frequencies used. All the frequencies I could hear are in group 'Charlie', now known as group 'Quebec' (Q) on the UFO satellites. Group Q comprises the following 25 kHz wide downlink frequencies (uplink frequencies are 41 MHz higher):

images ufo fltsatcom jpgQ1 250.650 MHz (Fleet Broadcast)
Q2 252.150 MHz (Navy Channels)
Q3 253.850 MHz
Q4 255.550 MHz
Q5 257.150 MHz
Q6 258.650 MHz
Q7 265.550 MHz
Q8 267.050 MHz
Q9 269.450 MHz
Q10 269.950 MHz
Q11 260.625 MHz (DoD Channels)
Q12 260.725 MHz
Q13 262.125 MHz
Q14 262.225 MHz
Q15 262.325 MHz
Q16 262.425 MHz
Q17 263.825 MHz
Q18 263.925 MHz

So far, I have heard sporadic voice traffic on channels Q2, Q3, Q4, Q5 and Q6 and something, albeit rather weak on Q7. It seems as if the satellite I am hearing is UFO-7 which is situated over the Atlantic. But is this traffic really pirates using the satellites on purpose, or is it something else? Surely there is no longer the need, in Brazil or other countries, to use US military satellites for communications, especially now that mobile phones and mobile coverage are virtually ubiquitous?

A quick look at the Brazilian frequency allocation table, the Plano de Destinação de Faixas de Freqüência, shows us that the frequency range 270 - 326.8 MHz is assigned to the fixed and mobile service, and in particular to public correspondence. So the frequencies are quite legally in use for various communication services; that they are being relayed by the satellite is incidental and a result of the fact that the uplink frequencies are used differently in different parts of the world. So no Brazilian pirate radio mafia trying to jam US military satellites after all then? What a shame, it seemed like such a good story.

Originally posted by admin of Wireless Waffle on Friday 31 August, 2007, 10:48 - Pirate/Clandestine

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ACORDE - Broadband Railway Internet Access on High Speed Trains Via Satellite Links

BROADBAND INTERNET ACCESS ON HIGH SPEED TRAINS

ACORDE's railway Internet access communications system (ACVSAT-Train-Ku) combines a bidirectional satellite link with a distribution system on the train. The distribution system (wireless LAN and optical fibre) is also bidirectional within the train itself, linking the satellite terminal and the train users.

The ACVSAT-Train-Ku establishes a connection with a stationary GEO satellite, assuring data rates of at least 4Mbit/s in the downlink and at least 2Mbit/s in the uplink. These data rates are functions of both HUB and satellite transponders, and can be improved by increasing transmit power. These data rates have been successfully tested with the train running at 350km/h.

The satellite link should be provided by a satellite operator which will rent the required bandwidth (for example: 7Mhz for 2+4Mbit/s) to the railway operator. Should the data-rate required by the services provided to each train be lower than 2+4Mbit/s, the 7MHz bandwidth rented from the satellite operator could be shared by several trains without additional HW nor SW modification.

The Internet connection should be provided by an ISP (Internet Service Provider); the railway operator should become the ISP to keep control of the system and increase the business revenue.

SYSTEM DESCRIPTION

The ACVSAT-Train-Ku is composed of a communications subsystem, a pointing subsystem and a distribution subsystem.

COMMUNICATION SUBSYSTEM

The communications subsystem possesses:

• Antenna
• Transmitter
• Modem
• Router IP connectivity

POINTING SUBSYSTEM

This subsystem performs the satellite acquisition and tracking. Three axes can be moved in order to maximise the received or transmitted signal, i.e., azimuth, elevation and feeder polarisation. Several elements are required in the pointing subsystem:

• IMU (Inertial Measurement Unit)
• AGC (Automatic Gain Control)
• Control unit

  

DISTRIBUTION SUBSYSTEM

An optical fibre connection is established between the central server and each train car where the conversion from optical to radio domain, and vice versa, takes place. The signal is eventually distributed to the passengers by means of WiFi IEEE802.11g / WiMax IEEE 802.16 access points.

Based on ACORDE's solution, both passengers and rail operators can benefit from the following services:

WIRELESS ACCESS TO BROADBAND INTERNET FOR THE DURATION OF THE TRIP

Via the Internet:

• Web surfing
• MSN
• Voice over IP connectivity (Skype)
• Email

Via railway operator's Intranet:

• On line games
• Trip maps and facts
• Ticket reservations and sales
• Video streaming
• Electronic newspapers

Passengers willing to use the Internet access service should purchase a prepaid card on the train. Together with the prepaid card users will be provided with a username and password to log on to the system.

IP-BASED VIDEO SURVEILLANCE SYSTEM (CCTV)

The recorded picture on our high speed train CCTV system can be centralised and monitored from a control room. Staff can receive silent alarm messages or even pictures with regard to passenger incidents.

Other specifically anti-terrorism technologies, such as chemical sniffers and radiation detectors, can also be combined into the system.

RAILWAY MEASUREMENT SYSTEM

ACORDE's communications system allows railway operators to implement real-time telemetry services for the railway system by means of a 'laboratory car' carrying the measurement equipment for rail wheels, overhead power cable checks, acceleration on train axles, vibrations, etc.

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