CIS FSK 200/1000

FSK 200/1000 is a technical name for a digital mode used by Russian Intelligence and possibly also Diplomatic stations. The name stands for its baud rate and shift - 200 bd speed, 1000 Hz shift between tones.

Aggiungi didascalia

The messages are encrypted bitstreams, sent in 288-bit blocks. Each block begins with control bytes 0x7D 0x12 0xB0 0xE6. The first two blocks of each message are significant, containing information on the amount of blocks, communication link ID, day of the month, serial number, message type, possibly the amount of encoded groups, and encoded decryption information.

A short recording may be heard  here

Below is an example of a FSK 200/1000 decoded transmission: you can see the mentioned keys (link ID, day of the month,...): reception was made on 17 November at 2020z, on 8123.0 KHz/USB:

----------------------------------------------------------
Block No 0 : Total Message Size 4 blocks : This transmission contains one message.
7d,12,b0,e6,00,00,00,00,00,00,60,00,10,00,00,00,00,08,20,04,00,04,00,08,40,0b,40,06,70,03,70,0e,20,0f,90,08
Block No 1  : Link ID 28680  : 17th of month  : Msg Number 002 : Msg Type 07145 : Group Count (?) 4
22796 00000 00000 00606 56197 35395 00893 60555
7d,12,b0,e6,00,33,15,00,b9,40,e0,e0,9c,10,7a,00,0a,02,00,05,82,0e,d8,0e,ba,3c,84,78,53,db,06,12,25,10,89,03
Block No 2
7d,12,b0,e6,00,55,00,00,00,00,00,00,00,00,00,00,00,0a,00,0f,00,0a,00,09,00,01,00,00,00,03,00,04,00,05,00,04
----------------------------------------------------------
Block No 0 : Total Message Size 4 blocks : This transmission contains one message.
7d,12,b0,e6,00,00,00,00,00,00,60,00,10,00,00,00,00,08,20,04,00,04,00,08,40,0b,40,06,70,03,70,0e,20,0f,90,08
Block No 1  : Link ID 28680  : 17th of month  : Msg Number 002 : Msg Type 07145 : Group Count (?) 4
22796 00000 00000 00606 56197 35395 00893 60555
7d,12,b0,e6,00,33,15,00,b9,40,e0,e0,9c,10,7a,00,0a,02,00,05,82,0e,d8,0e,ba,3c,84,78,53,db,06,12,25,10,89,03
Block No 2
7d,12,b0,e6,00,55,00,00,00,00,00,00,00,00,00,00,00,0a,00,0f,00,0a,00,09,00,01,00,00,00,03,00,04,00,05,00,04
----------------------------------------------------------
Block No 0 : Total Message Size 2 blocks : This transmission contains 0 messages.
7d,12,b0,e6,00,00,00,00,00,00,30,00,08,00,00,00,00,04,10,02,00,02,00,04,20,05,a0,03,38,01,b8,07,10,07,c8,04
Block No 1  : Link ID 28680  : 17th of month  : Msg Number 002 : Msg Type 07145 : Group Count (?) 4
22796 00000 00000 00606 56197 35395 00893 60555
7d,12,b0,e6,00,33,15,00,b9,40,e0,e0,9c,10,7a,00,0a,02,00,05,82,0e,d8,0e,ba,3c,84,78,53,db,06,12,25,10,89,03
Block No 2
7d,12,b0,e6,00,55,00,00,00,00,00,00,00,00,00,00,00,0a,00,0f,00,0a,00,09,00,01,00,00,00,03,00,04,00,05,00,04
----------------------------------------------------------

FSK 200/1000 also has a concept of empty messages. These are always 4 blocks long, and include "00000" groups.
FSK 200/1000 operates in schedules of three transmissions, spaced 10 minutes apart.
The further transmissions are transmitted on lower frequencies. The frequency usage indicates worldwide operation. There also are unscheduled transmissions, using the communication link ID "00000", which may not repeat in regular manner.

FSK 200/1000 contents can be decoded using the free program Rivet, as in the following screenshot:

sources and resouces:
https://github.com/IanWraith/Rivet 
http://priyom.org/number-stations/digital/fsk-2001000.aspx
https://github.com/IanWraith/Rivet/wiki/GW-100-Baud-FSK

XSQ - Guangzhou Coast Station

Guangzhou Coast Station is one of the China's largest coast station in southern China and was established in October 14, 1949.

Guangzhou coast station is directly under the Guangdong Maritime Safety Agency. The staff is 176 of employees people: 122 people in the post, four senior titles, intermediate title 12 people, technical staff of 76 people.

Main functions:

1, implementation of the party and state policies and directives and superior decisions;

2, responsible for the South China Sea maritime safety information broadcast, distress and safety duty and other services, to provide security communications for ships at sea;

3, provide maritime radio communication services and special communications tasks assigned by superiors for international and domestic shipping;

4, provide ship-shore communication technology and social counseling services, ship guided escrow and other public services;

5, take charge of the Guangdong Maritime Safety Administration water traffic safety supervision communications, information systems, communication lines, communication networks and other construction and maintenance;

6, in accordance with the authorization, responsible for issuing work within the jurisdiction of the ship station licens

From January 1, 2014, Guangzhou coast stations offer free boat ship - shore public (official) communications services.

 radio station long line facilities and equipment

Guangzhou coast station is a three-site formula coast station:

Wanqingsha: receiving station
Nangang: center console (located in Huangpu, Guangzhou Development Zone)
Luogang: transmitting station(Eastern Guangzhou City, covering about 35 thousand square meters)

and other nine minor base stations.

eMail: gzrdo@gzrdo.com

Address: Room 1101, No. 40, Guangzhou Bin Jiangxi
Radio Telephone: 020-83295815 Office Tel: 020-83295554 

Guangdong Coast VHF system server, automatic DSC, AIS terminal

Swiss 2 x 100Bd/170Hz VFT system

fig 1

VFT 2 x FSK 100Bd/170Hz system used by Swiss Air Force, likely the modem is the "Telematik-Set TmS-430". Channels are simply arranged as in fig. 1.

fig. 2

fig. 3

fig. 4

why HF ?

in the age of Internet and Satcom why they should still use HF?

Prior to the launch of communications satellites in the 1960s, high frequency (HF) radio was the principal means to communicate over the horizon. Satellite links permitted users to communicate at higher data rates, and over time HF was relegated to a backup role within the militaries of the United States, Western Europe, and the former Soviet Union. However, the limitations of satellites became clear in the Cold War era, as satellites were not only vulnerable to jamming and physical damage, but also required a supporting infrastructure that was expensive to build and maintain. The last two decades have resultantly seen resurgence in HF radio, led by a new generation of automated equipment with improved link reliability, connectivity, and speed that offered many of the benefits of satellite technology at a fraction of the overall cost. HF now serves as the principal backup in most ground- and ship-based configurations, and the primary backup in installations prioritizing lowest total cost of ownership.

Today, amidst the post 9/11 requirements for continuity of operations and a failsafe means of voice and data communication, HF equipment serves as a critical component in most emergency preparedness wireless communications plans. HF radio provides an additional layer of protection against total loss of communication when infrastructure-dependent communications are disabled, destroyed, or unavailable.

Benefits of HF Technology:

MINIMAL INFRASTRUCTURE REQUIREMENTS
An HF radio network requires absolutely no infrastructure. Unlike conventional land lines, cellular and satellite telephones, and Voice Over IP, an HF radio user can communicate with another HF radio user without any infrastructure apart from the equipment and housing area, minimizing both cost and susceptibility to damage.
   
MINIMAL COST OF OWNERSHIP
HF is the most economical means of failsafe communication. After the initial investment in equipment and installation is made, there are no call or line costs. Furthermore, such equipment is ruggedized and built to withstand extreme conditions over many years, thereby significantly reducing costs of the usage period.

TRUE HEMISPHERIC COVERAGE
HF, or short-wave, radio is the best suited technology to communicate over long distances. When coupled with solid-state kilowatt amplifiers, HF can serve as a primary or emergency means of communication to and from any point in the world.

SURE AND SECURE COMMUNICATIONS
For sensitive communications where security is essential, voice and data encryption is a readily available option with HF radio with differing levels of security based on the respective communications requirement.

FULL FEATURED
In addition to voice, HF radios come with options that allow for telephone, fax, email, and high speed data.

INTEROPERABILITY
HF radios can communicate with existing VHF and UHF systems, cellular telephones and land lines through developments in cross-patching technology.

[ source sunair ]

DGPS: the new frontier of DXing ?

Differential Global Positioning System (DGPS) is an enhancement to Global Positioning System that provides improved location accuracy, from the 15-meter nominal GPS accuracy to about 10 cm (!) in case of the best implementations.
DGPS uses a network of fixed, ground-based reference stations to broadcast the difference between the positions indicated by the satellite systems and the known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount. The digital correction signal is typically broadcast locally over ground-based transmitters of shorter range. Just these stations are called DGPS Beacons.

DGPS serving marine navigation

DGPS serving inland users

Differential correction techniques are used to enhance the quality of location data gathered using global positioning system (GPS) receivers. Differential correction can be applied in real-time directly in the field or when postprocessing data in the office. Although both methods are based on the same underlying principles, each accesses different data sources and achieves different levels of accuracy. Combining both methods provides flexibility during data collection and improves data integrity.


Real-time DGPS
occurs when the base station calculates and broadcasts corrections for each satellite as it receives the data. The correction is received by the roving receiver via a radio signal if the source is land based or via a satellite signal if it is satellite based and applied to the position it is calculating. As a result, the position displayed and logged to the data file of the roving GPS receiver is a differentially corrected position.

Postprocessing Correction
Differentially correcting GPS data by postprocessing uses a base GPS receiver that logs positions at a known location and a rover GPS receiver that collects positions in the field. The files from the base and rover are transferred to the office processing software, which computes corrected positions for the rover's file. This resulting corrected file can be viewed in or exported to a GIS.

postprocessing

These signals can be found on LF, on the channels listed in the Marine Beacon Bandplan in Section Nine; in Europe the band covers 283.5 to 315 kHz, but in some other parts of the world 315 to 325 kHz are also used.  DGPS beacons are heard using G1D modulation with Minimum Shift Keying (MSK), a frequency shift keying mode with very small bandwidth, and their sound resembles a RTTY/Navtex signal. 

DGPS spectrum [1]

The baud rate in many cases will be 100 bps though there are still quite a lot of 200 bps beacons in some parts of the world (especially North America). Baud rate setting may be set manually or automatically by the decoder.

tuning a DGPS beacon on 286.5 KHz

You can use software such as DSCdecoder or Multipsk to decode DGPS signals and see where they are coming from: DSCdecoder my be downloaded from the following site , it has a 21 days test period and costs Euro €25 (plus VAT for EUresidents) for personal use. Personally I use Multipsk and SkySweeper (see below).

Pay attention to the false decodes which return "exotic" beacons. The reasons for these being created are more complex, but sometimes not being tuned in properly, or even loud static bursts can start the decoder going and ‘invert’ signals , and this can be a problem when unattended monitoring is being attempted, and the user can’t see what is causing it. Moreover, most Message Types used by DGPS beacons fall into a limited category, so anything outside of these should be treated with caution, especially if only one decode ‘frame’ is received, and not multiple identical decodes. 

As David GM8XBZ say:
"The station details that a decoding programme gives are from a lookup table that it holds. When it gets a station reference, it prints out the info it has in the software. All you receive is the station number. If that is an error, the software doesn't know.
The big clue, besides the range and time, is the Z-count value. In a 'good' decode, this should be the same as the time-stamp from the PC.  for example, at 21:12:30, the Z-count should be close to 1230 (12 min 30secs)."

DGPS Message Types
There are a number of different ‘Message Types’ broadcasted by the various DGPS beacons, and below is a list of what these are in my log and what they mean:

Message Type: 1 Differential GPS Correction
Message Type: 3 GPS Reference Station Parameters
Message Type: 5 GPS constellation health
Message Type: 6 GPS null frame
Message Type: 7 DGPS Radiobeacon Almanac
Message Type: 9 GPS Partial Correction Set

but there are up to 63 message types:

DGPS message types [1]

DGPS decoders and reception

Below a DGPS transmission received just some minute ago from station number 469 (Porquerolles FRA 286.5 Khz TXID 339 100bps): the same transmission has been decoded with Multipsk and SkySweeper (this one showing local time, UTC -1):

working 469 DGPS beacon with Multipsk

working 469 DGPS beacon with SkySweeper

When loggin a DGPS beacon, its "reference ID" is indicated as "station number" by decoders: this number is usually taken as its callsign while the TX ID number is noted in details within the its baud rate. In the above case I'll log:

00286.5 469: DGPS Porquerolles, FRA 1243 TXID #339 100bps

The "station number" helps to identify the received beacon. As seen, two numbers exits (see the table below): 

1. GPS reference station number
2. DGPS broadcast station number (see the table below)
The numbers itself are not part of the RTCM standard, but are assigned by IALA. Some authorities stick to the RTCM standard and send the reference station number, others use the broadcast station number.
DGPS beacons in the UK, Norway and Denmark, for example, transmit reference station numbers, while those in The Netherlands, Germany, Sweden and Finland send the broadcast station number.
This confusion has not been resolved so far.

Stations Numbers [1]

European Differential Beacon Transmitters (European DGPS Network)

Trinity House have changed the frequency of many of the UK DGPS beacons, see:
http://www.trinityhouse.co.uk/pdfs/gps_ukireland.pdf 
  

 

some DGPS web resource

[1] https://gpsd.googlecode.com/files/rtcm-sc104-transmission-characteristics-of-marine-differential-gps-stations.pd

[2] http://www.ndblist.info/datamodes/worldDGPSdatabase.pdf

[3] ndblist.info

Happy DGPS DXing !