Pocsag Decoder Software Free

RADIORAFT 3.21
RADIO SIGNAL DECODER SOFTWARE
Copyright (c) 1996-2002 by FrancoisGuillet
All rights reserved.

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MODES AND OPTIONS USER'S GUIDE

The 30 modes ofRadioRaft

(1) Pocsag needs an interface with hysteresis adjustment

Contents: See also the RADIORAFT USER'S GUIDE

The menu 'Modes' in RadioRaft allows you to select a mode. Thecommand 'Options..' in this menu allows you to access options available for thecurrent mode.
The key F6 permits you to access directly to the menu 'options'.

ASYNCHRONOUS orQUASI-SYNCHRONOUS MODES

A receiver with a discriminator output or 9600 bps packet radio output; A PC with a USB port or serial port (also PCI or PCMCIA card) An interface: USB or RS232 for POCSAG, 2 level Flex and Mobitex. One side of the interface is connected to the discriminator output, the other side to the PC's USB or serial port. POC32 Implementation Guide. Version: 1.0.19 Date: March, 1997 Platform: Win32 (Windows 95 or Windows NT/I386) Language: Microsoft Visual C V4.X and MFC extensions Description: POC32 is a POCSAG protocol en-/decoder software.

These modes use a start bit (0) at the beginning of each character, and one or severalstop bits (1) at the end. Each character can be transmitted at any time. The stop bit hasduration of 1 or 1.5 times the duration of other bits. Transmissions of this type arenumerous, especially those using the Baudot code.

Nevertheless many stations use a stop bit of normal duration and transmit charactersconsecutively, resulting in a quasi-synchronous transmission.

Modes of this type that RadioRaft decodes are:

ASCII

The names of ASCII modes in RadioRaft are:

• ASCII-1: 7 bits code, 1 stop bit, no parity.
• ASCII-1-0: 7 bits, 1 stop bit, even parity
• ASCII-1-1: 7 bits, 1 stop bit, odd parity
• ASCII-2: 7 bits, 2 stop bits, no parity.
• ASCII-2-0: 7 bits, 2 stop bits, even parity
• ASCII-2-1: 7 bits, 2 stop bits, odd parity
• ASCII8-1: 8 bits, 1 stop bit, no parity.
• ASCI8-1-0: 8 bits, 1 stop bit, even parity
• ASCI8-1-1: 8 bits, 1 stop bit, odd parity

ASCII characteristics

Protocol: 1 start bit (0), 1 codeword, 1 or none parity bit, 1 or several stop bits(1) of normal duration.

Code: 7 bits ASCII characters also known as ITA 5 or IRA (128 characters set). 8bit characters are also sometimes used (256 characters set).

Current speeds: 110, 200, 300, 600, 1200 bauds

Current modulation: FSK

ASCII options

Parity check (enabled by default)

This option enables or disables the parity check.

If it is disabled, erroneous characters are displayed as they would have no parityerror. A wrong character can be displayed in place of the right one.

If it is enabled and there is a parity error, an error character is displayed (ASCII126, ~).

This option has no effect on ASCII modes without parity.

Synchronous treatment (enabled by default)

RadioRaft supposes that characters are transmitted consecutively with no delay betweenfollowing characters, resulting in a quasi-synchronous transmission. This improves thedecoding.

You must disable this option with pure asynchronous transmissions (for ex. manualtransmission with delay between characters).

Invert ASCII code

Inverts the order of low and high bits in the ASCII code. Generally you don't need toenable this option because ASCII transmissions send always the low bit the first, whatRadioRaft is expecting.

UOSAT

UOSAT-Data Oscar-11 characteristics

Code, protocol: same as ASCII-2-0 or ASCI8-1-0

Current speed: 1200 bauds

Current modulation: FFSK 1200/2400 Hz

Use: UOSAT data from the satellite OSCAR-11: information or telemetry.

UOSAT options

Same as ASCII. UOSAT data transmissions send ASCII text with or without a parity bit.By default RadioRaft doesn't check the parity.

BAUDOT

The names of Baudot modes in RadioRaft are:

• BAUDOT: pure asynchronous Baudot mode.
• BAUDOT-1: Baudot mode with 1 stop bit and handled as a synchronous mode.
• BAUDOT-2: Baudot mode with 2 stop bits and handled as a synchronous mode.
• BAUDOT1-1: Baudot mode with 1 stop bit and 1 odd parity bit and handled as a synchronous mode.

Baudot characteristics

This mode is sometimes named RTTY.

Protocol: 1 start bit (0), 1 codeword, 1 or several stop bit (1). Generally thestop bit has duration of 1.5 times the duration of other bits.

Code: Baudot or ITA2, 32 characters set, 5 bit words. Well known code, it is themost commonly used (telex, press agencies..).

Current speeds: 45, 50, 75, 100, 150, 200 bauds

Current modulation: FSK

Main use: press agencies, aeronautical weather report, radioamateur, military,ship traffic

This name comes from J.BAUDOT, French engineer who invented in 19th century the 5elements telegraph (1 element for each finger, a character was coded with the hand!)

Baudot options

These options are available only in manual mode (by clicking on 'Manual' inthe main menu or hitting key F4) and in the pure Baudot mode (not available in Baudot-1,Baudot-2, Baudot1-1).

Auto-shift (enabled by default)

RadioRaft finds automatically the right shift

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Reversed shift

Clicking on 'Reversed shift' inhibits the automatic shift detection, and thenswitches to the normal or reversed shift, which can improve the decoding if the signal isdisturbed.

ARQ SEMI-DUPLEX MODES

These modes are only used in bilateral transmissions. A station transmits the text inblocks of several characters, then switches to reception and waits for an acknowledgmentof its addressee (ARQ = Automatic Repetition reQuest).

The code or the protocol permits to know if errors occur in a block.

In case of negative acknowledgment, the block is repeated.

The 2 stations are synchronized.

The direction of the transmission can be reversed by the transmission of a particularcharacters sequence. The 2 stations are generally on the same frequency, but it is not arule (for ex. ship traffic uses separate transmission/reception frequencies).

RadioRaft receives the blocks and ignores acknowledgments.

Repetitions are canceled to obtain a very readable text (in case of bad link betweenthe 2 stations, repetitions can indeed be very frequent, up to several minutes). Howeveran option allows you to view the repetitions and the special characters (menu'Display/Display control codes').

Modes of this type are:

ARQ-6/90, ARQ-6/98

Protocol: transmission of blocks of 6 characters. Duration of a block 210 ms, timebetween 2 blocks 240 ms for ARQ-6/90 and 280 ms for ARQ-6/98.

Code: CCIR-476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 200 bauds

Current modulation: FSK

Main use: diplomatic traffic

DUP-ARQ

Protocol: transmission of 32 bit blocks containing:

• 1 parity bit
• 5 bits checksum word (Hamming code)
• 2 codewords
• 1 bit
• 3 codewords

The checksum and the parity bit permits to detect errors in the whole block.

Code: Baudot (ITA2), 32 characters set, 5 bit words.

Current speed: 125 bauds

Current modulation: FSK

Main use: diplomatic traffic

PACTOR-I

RadioRaft decodes only PACTOR version I.

Pactor-I characteristics

Protocol: transmission a phasing byte followed by 96 or 192 bits block containing:

• a header byte
• 8 or 20 data bytes (8 at 100 bauds, 20 at 200 bauds)
• a status byte
• a 16 bits CRC (cyclic redundant checksum) based on a polynomial code that allows error detection.

Code: none. Any type of data can be placed in the data bytes. When text istransmitted, either ASCII 8 bits is used or text is compressed with an Huffman code.

Current speed: 100 and 200 bauds

Current modulation: FSK

Main use: radioamateur, humanitarian organisations, miscellaneous

Pactor-I options

Checksum

If you disable this option (enabled by default), RadioRaft will not check the CRC andcould display blocks with errors.

Auto CRC

Some PACTOR-I versions use special CRC for a private use. With this option enabled,RadioRaft decodes the common 'public' version (CRC=0) or all other'customized' version by detecting the right CRC.

Custom CRC

RadioRaft displays in this field the CRC it detects. You can also enter yourself theCRC. This permits to reduce the time to synchronize or to prevent RadioRaft from decodingother Pactor mode (Auto CRC must be set).

SI-ARQ

Protocol: transmission of blocks of 4, 5, 6 or 7 characters with alternatepolarities except in case of repetition. The time between 2 blocks is equal to the time ofa block.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 96 bauds

Current modulation: FSK

RadioRaft particulars: In RadioRaft the modes are named: SI-ARQx with x=4, 5, 6or 7 depending on the block size.
The masking of repetitions, contrarily to SITOR-A, never entails a loss of text.

SITOR-A

Protocol: CCIR Recommendation 476-4. Transmission of blocks of 3 characters.Duration of a block 210 ms, time between 2 blocks 240 ms.

Code: CCIR 476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK (current shift: 170 Hz).

Main use: ship traffic, radioamateur, police

RadioRaft particulars: If 2 successive blocks are similar, RadioRaft considersit is a block repetition, and does not display the second block. This criterion ofdecision that there is repetition can sometimes entail the loss of text (for ex. duringhighlighting, several blocks '---' are transmitted, and RadioRaft wronglyconsiders there are repetitions. Nevertheless this event is rare.
RadioRaft identifies the transmission of a selective call and display the callsignfollowing by the text: {Selcall}.
RadioRaft doesn't not translate the 4 letters callsign in digits for the maritime stationidentification.
RadioRaft doesn't support the new CCIR Recommendation 625-2 for the 9 digits ship stationidentification.

The ear can easily identify this mode: it sounds like the chirping of the cricket.

SWED-ARQ

Protocol: transmission of blocks of 3, 9 or 22 characters.

• Duration of a 3 characters block 210 ms, time between 2 blocks 240 ms.
• Duration of a 9 characters block 630 ms, time between 2 blocks 240 ms.
• Duration of a 22 characters block 1540 ms, time between 2 blocks 240 ms.

Code: CCIR 476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK

Main use: diplomatic traffic

RadioRaft particulars: The change of block length and timing is automaticaccording to the link conditions. RadioRaft detects automatically the change of blocksizes.
When block is 3 characters length, this mode is strictly identical with SITOR-A. RadioRaftdecodes the 3 characters block of the SWED-ARQ mode as the SITOR-A mode, the onlydifference being that a selcall is not identified.
Repetitions are canceled as in SITOR-A.

ARQ FULL-DUPLEX MODES

These modes are generally used for bilateral connections and need these stations havesimultaneous transmission and reception on separate frequencies.

They are used for the military and diplomatic traffic and were used on internationaltelex circuits. In case of bad links between the two stations, there are repetitions bycycles of 4, 5 or 8 characters.

As with ARQ semi-duplex modes, RadioRaft inhibits repetitions, except if the oppositeoption is set (menu 'View/Display control codes').

ARQ-E

Protocol: 3 or 7 erect characters follow 1 reversed character, and so on. In caseof repetition, a special character RQ is transmitted. It is followed par 3 or 7 repeatedcharacters.

Code: ARQ-E, 35 characters set, 7 bit words. 32 characters are formed by: 1 bit0, 5 bits of the Baudot code and 1 odd parity bit for the detection of errors. 3supplementary characters are added (RQ and synchronization alpha and beta).

Current speeds: 96, 192 bauds

The characters polarity indicator is always 0101 or 1111 or respectively 7F7F or 7777if the shift is reversed.

Main use: military and diplomatic traffic

ARQ-E3

Protocol: 1 erect character is followed by 3 or 7 reversed characters, and so on.In case of repetition, a special character RQ is transmitted. It is followed par 3 or 7repeated characters.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 48, 96, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic

RadioRaft particular: the characters polarity indicator is always 0101 or 1111or respectively 7F7F or 7777 if the shift is reversed.

ARQ-M2, SI-FEC

Arq-m2 characteristics

Protocol: CCIR 342 and 242. It allows the division of the link in 2 transmissionchannels, characters interleaved. The characters have a normal or reversed polarity.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 96, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic, formerly international telex circuits

RadioRaft particular: the characters polarity indicator in hexadecimal indicatesthe polarity of the 16 latest received characters (for more details see 'The firstscreen line' in the main documentation).
These bit patterns are defined by the CCIR but some stations use different patterns.RadioRaft decode all of them.
In CCIR-342, the pattern is 1D1D (1717 with reversed shift).
In CCIR-242, 5555.

Arq-m2 options

This menu allows you to select the channel. You can select 1 of 2 channels, named A andB.

The choice 'All' allows to simultaneously view the 2 channels: it isinteresting to see if there is traffic without having to switch from one channel toanother. In this case 2 channels being character by character interleaved, you have not aclear text, except if the traffic is transmitted on only one channel, while idlecharacters are transmitted on the other one.

SI-FEC

This mode is unusual. It is not implemented in RadioRaft as a full mode, but the ARQ-M2RadioRaft routine can automatically decode it, without undertaking the error correction.
The choice of the channel has no importance: the 2 channels transmit the same message.
The polarity indicator is 5555.

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ARQ-M4

Arq-m4 characteristics

Protocol: it is defined by CCIR 342 and 242 and allows the division of the link in4 transmission channels, characters and bits interleaved.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 96, 192 bauds

Main use: military and diplomatic traffic, formerly international telexcircuits.

RadioRaft particulars: characters have a normal or reversed polarity. Thepolarity indicator in hexadecimal indicates the polarity of the 16 latest receivedcharacters (for more details see 'The first screen line' in the maindocumentation).
The bits patterns are defined by the CCIR but some stations use different patterns.RadioRaft decode all of them.
In CCIR-342, the pattern is 1D1D (1717 with reversed shift).
In CCIR-242, 5555.

Arq-m4 options

This menu allows you to select the channel. You can select 1 of 4 channels, named A toD.
You can also see the traffic of both channels A and C, or B and D.

The choice 'All' allows to simultaneously view the 4 channels: it isinteresting to see if there is traffic without having to switch from one channel toanother. In this case the channels being character by character interleaved, it isdifficult to have a clear text, except if the traffic is transmitted in only one channel,while filling characters are transmitted in the others.

ARQ-N

Protocol: all characters are transmitted consecutively with the same polarity. Arepetition consists of the RQ character followed by 3 repeated characters.

Code: ARQ-E, 35 characters set, 7 bit words. 32 characters are formed by: 1 bit(0), 5 bits of the Baudot code and 1 odd parity bit for the detection of errors. 3supplementary characters are added (RQ and synchronization alpha and beta).

Current speed: 96 bauds

Current modulation: FSK

The polarity indicator is always 0000 (or FFFF if the shift is reversed).

POL-ARQ

Protocol: all characters are transmitted consecutively with the same polarity. Arepetition consists of the RQ character followed by 4 repeated characters.

Code: CCIR-476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK

Main use: diplomatic traffic

Some stations use a similar mode at 50 bauds. RadioRaft can decode itbut messages are always encrypted.

FEC MODES

These modes are used for broadcasting (e.g. transmission from a station tothe destination of one or several others, with protection against errors: FEC = ForwardError Correction).

AUTOSPEC

Protocol: characters are transmitted consecutively.

Code: Bauer code, 32 character set, 10 bit words (5 bits like ITA2 and 5 bitsfor the error detection and correction by a Hamming code).

Standard speeds: 62.3, 68.5, 102.6 and 137 Bauds.

Current modulation: FSK

CIS11

Protocol: characters are transmitted consecutively.

Code: 11 bit words, 32 characters set (5 bits of the Baudot code, 2synchronization bits and 4 bits for the error detection and correction by a Hamming code).

Current speeds: 75, 100 bauds.

Current modulation: FSK

Main use: aeronautical weather report from eastern Europe.

DGPS

Dgsp characteristics

Protocol: transmission of frames of codewords. The number of words in a framedepends on the message type and is variable in the same type, not exceeding 33.
The first codeword contains an 8 bits preamble, the message type (6 bits) and the stationId (10 bits).
The second codeword gives the 'Modified Z-count' (13 bits) which is the starttime of the next frame preamble, the sequence number (3 bits), the length of the frame (5bits) which is the number of codewords following this one and the station health (3 bits).

The 2 first codewords are common to all messages. The meaning of the next ones dependson the message type.

Code: 30 bit words:

• 24 data bits
• 6 bits for the CRC (cyclic redundant checksum), based on a polynomial code that allows error detection.

Current speeds: 100, 200 bauds. Other rates are also possible but not used.

Current modulation: MSK

Main use: worldwide transmissions of corrections to improve the accuracy of datareceived from GPS devices. The transmitters are located on the costs and intended to themaritime service. They transmit in the hectometric band around 300 Khz, with a rangearound 100-200 Kms.

RadioRaft particulars:

• A real MSK demodulation would require the receiver passes audio frequencies as low as 100 hz. The most of the receivers doesn't permit it. So RadioRaft demodulates DGPS by using the ordinary FSK demodulation routine.
  IMPORTANT: tune preferably your receiver to low audio frequencies around 300-800 Hz to get the best results. It is due to the very low shift used by MSK (50 hz at 100 bauds).
• RadioRaft decodes each field of the 2 first words which are common to all messages and give the identity of the station. The next words are displayed as 3 hex data bytes. Nevertheless RadioRaft decodes the whole messages 3 (reference station parameters), 5 (satellite constellation health), 7 (station almanach) and 16 (Ascii plain text). The occurence of these messages depend on the stations. Messages 16 are rare.
• MSK is very sensitive to noise and interferences. Use narrow filter with your receiver.

Dgsp messages display

Refer to recommendation ITU-R M.823 to interpret the different fields. Herethey are in brief:

• First line:

MSG xx Station463 Z-Time 37:4.2 Sequence:0 Length:12 Health:0

MSG: xx is the message type
Station: reference station number
Z-time: modified Z-count, time at which the corrections are computed in unitof 0.6 sec. See the options.
Sequence: sequence number (0-7), increments on each frame
Length: frame length, number of words following this one (0-31)
Health: station health (0-7)

• Other lines:

  • All messages but 3, 5, 7, 16, data are displayed as hex values:

Data: 012345 6789AB 1A2B3C..

• Message 3 (reference station parameters, coordinates according to WGS84 format):

Station coordinates (mtrs): X=4296717.12 Y= -263398.80 Z= 4690668.64

• Message 5 (satellite constellation health):

Satellite 23 IOD:0 Datahealthy Sat S/N not tracked Sat healthy
No new IOD Loss of satellite warning in (mn): 35

For each satellite:

Satellite number
IOD: Issue Of Data
Data healthy (or unhealthy)
Sat S/N not tracked (otherwise the signal to noise ratio is given inDb(Hz))
Sat healthy (consider sat healthy even if data unhealthy)
No new IOD (or New IOD soon)
Loss of satellite.. if scheduled, time remaining before loss

• Message 7 (station almanach):

Position: 47°38'48.1' North 3°30'36.0'West
Range: 170 Km Frequency: 298.0 KhzR/beacon operation normal
Tx.Id: 332 100 Bauds MSK synchronous No added coding

For each beacon in the almanach:

Position: lattitude and longitude of the station
Range: beacon service range
Frequency: beacon frequency
R/beacon operation normal: health of the beacon as plain text
Tx.Id: transmit station number. Don't confuse with 'referencestation number'.
100 bauds: data rate of the beacon
MSK: the modulation the beacon is using (also FSK)
Synchronous: synchro type (also asynchronous)
No added coding: broadcast coding (also 'FEC coding')

Messages 16, ASCII text information follows this header.

Dgsp options

Stop on error

If an error is received in a word and this option is set, the next words are notdisplayed. RadioRaft is waiting for the next frame.

Display hex data

You may avoid to display hex data by disabling this option. Only the 2 first words in aframe are displayed.

Z-count in time format

Option by default: the time is displayed in the MM:SS.t format (t = tenths of second).If this option is not set, the time is displayed as received, i.e. in multiple of 0.6 sec.This is the time elapsed since the previous round hour, at which the corrections arecomputed.

FEC-A

Protocol: transmission of 2 channels, bits interleaved. The characters of a messageare transmitted in one of the 2 channels and the bits of an error correcting cyclic codein the second one.

Code: FEC-A, 7 bit words, 34 characters set. 32 characters are formed by: 1 bit(0), 5 bits of the Baudot code and 1 even parity bit for the detection of errors. 2supplementary characters are added (RQ and beta).

Current speeds: 96, 144, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic, news.

DUP-ARQ

Protocol: transmission of 32 bit blocks containing:

• 1 parity bit
• 5 bits checksum word (Hamming code)
• 2 codewords
• 1 bit
• 3 codewords

The checksum and the parity bit permits to detect errors in the whole block.

Code: Baudot (ITA2), 32 characters set, 5 bit words.

Current speed: 125 bauds

Current modulation: FSK

Main use: diplomatic traffic

PACTOR-I

RadioRaft decodes only PACTOR version I.

Pactor-I characteristics

Protocol: transmission a phasing byte followed by 96 or 192 bits block containing:

• a header byte
• 8 or 20 data bytes (8 at 100 bauds, 20 at 200 bauds)
• a status byte
• a 16 bits CRC (cyclic redundant checksum) based on a polynomial code that allows error detection.

Code: none. Any type of data can be placed in the data bytes. When text istransmitted, either ASCII 8 bits is used or text is compressed with an Huffman code.

Current speed: 100 and 200 bauds

Current modulation: FSK

Main use: radioamateur, humanitarian organisations, miscellaneous

Pactor-I options

Checksum

If you disable this option (enabled by default), RadioRaft will not check the CRC andcould display blocks with errors.

Auto CRC

Some PACTOR-I versions use special CRC for a private use. With this option enabled,RadioRaft decodes the common 'public' version (CRC=0) or all other'customized' version by detecting the right CRC.

Custom CRC

RadioRaft displays in this field the CRC it detects. You can also enter yourself theCRC. This permits to reduce the time to synchronize or to prevent RadioRaft from decodingother Pactor mode (Auto CRC must be set).

SI-ARQ

Protocol: transmission of blocks of 4, 5, 6 or 7 characters with alternatepolarities except in case of repetition. The time between 2 blocks is equal to the time ofa block.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 96 bauds

Current modulation: FSK

RadioRaft particulars: In RadioRaft the modes are named: SI-ARQx with x=4, 5, 6or 7 depending on the block size.
The masking of repetitions, contrarily to SITOR-A, never entails a loss of text.

SITOR-A

Protocol: CCIR Recommendation 476-4. Transmission of blocks of 3 characters.Duration of a block 210 ms, time between 2 blocks 240 ms.

Code: CCIR 476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK (current shift: 170 Hz).

Main use: ship traffic, radioamateur, police

RadioRaft particulars: If 2 successive blocks are similar, RadioRaft considersit is a block repetition, and does not display the second block. This criterion ofdecision that there is repetition can sometimes entail the loss of text (for ex. duringhighlighting, several blocks '---' are transmitted, and RadioRaft wronglyconsiders there are repetitions. Nevertheless this event is rare.
RadioRaft identifies the transmission of a selective call and display the callsignfollowing by the text: {Selcall}.
RadioRaft doesn't not translate the 4 letters callsign in digits for the maritime stationidentification.
RadioRaft doesn't support the new CCIR Recommendation 625-2 for the 9 digits ship stationidentification.

The ear can easily identify this mode: it sounds like the chirping of the cricket.

SWED-ARQ

Protocol: transmission of blocks of 3, 9 or 22 characters.

• Duration of a 3 characters block 210 ms, time between 2 blocks 240 ms.
• Duration of a 9 characters block 630 ms, time between 2 blocks 240 ms.
• Duration of a 22 characters block 1540 ms, time between 2 blocks 240 ms.

Code: CCIR 476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK

Main use: diplomatic traffic

RadioRaft particulars: The change of block length and timing is automaticaccording to the link conditions. RadioRaft detects automatically the change of blocksizes.
When block is 3 characters length, this mode is strictly identical with SITOR-A. RadioRaftdecodes the 3 characters block of the SWED-ARQ mode as the SITOR-A mode, the onlydifference being that a selcall is not identified.
Repetitions are canceled as in SITOR-A.

ARQ FULL-DUPLEX MODES

These modes are generally used for bilateral connections and need these stations havesimultaneous transmission and reception on separate frequencies.

They are used for the military and diplomatic traffic and were used on internationaltelex circuits. In case of bad links between the two stations, there are repetitions bycycles of 4, 5 or 8 characters.

As with ARQ semi-duplex modes, RadioRaft inhibits repetitions, except if the oppositeoption is set (menu 'View/Display control codes').

ARQ-E

Protocol: 3 or 7 erect characters follow 1 reversed character, and so on. In caseof repetition, a special character RQ is transmitted. It is followed par 3 or 7 repeatedcharacters.

Code: ARQ-E, 35 characters set, 7 bit words. 32 characters are formed by: 1 bit0, 5 bits of the Baudot code and 1 odd parity bit for the detection of errors. 3supplementary characters are added (RQ and synchronization alpha and beta).

Current speeds: 96, 192 bauds

The characters polarity indicator is always 0101 or 1111 or respectively 7F7F or 7777if the shift is reversed.

Main use: military and diplomatic traffic

ARQ-E3

Protocol: 1 erect character is followed by 3 or 7 reversed characters, and so on.In case of repetition, a special character RQ is transmitted. It is followed par 3 or 7repeated characters.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 48, 96, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic

RadioRaft particular: the characters polarity indicator is always 0101 or 1111or respectively 7F7F or 7777 if the shift is reversed.

ARQ-M2, SI-FEC

Arq-m2 characteristics

Protocol: CCIR 342 and 242. It allows the division of the link in 2 transmissionchannels, characters interleaved. The characters have a normal or reversed polarity.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 96, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic, formerly international telex circuits

RadioRaft particular: the characters polarity indicator in hexadecimal indicatesthe polarity of the 16 latest received characters (for more details see 'The firstscreen line' in the main documentation).
These bit patterns are defined by the CCIR but some stations use different patterns.RadioRaft decode all of them.
In CCIR-342, the pattern is 1D1D (1717 with reversed shift).
In CCIR-242, 5555.

Arq-m2 options

This menu allows you to select the channel. You can select 1 of 2 channels, named A andB.

The choice 'All' allows to simultaneously view the 2 channels: it isinteresting to see if there is traffic without having to switch from one channel toanother. In this case 2 channels being character by character interleaved, you have not aclear text, except if the traffic is transmitted on only one channel, while idlecharacters are transmitted on the other one.

SI-FEC

This mode is unusual. It is not implemented in RadioRaft as a full mode, but the ARQ-M2RadioRaft routine can automatically decode it, without undertaking the error correction.
The choice of the channel has no importance: the 2 channels transmit the same message.
The polarity indicator is 5555.

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ARQ-M4

Arq-m4 characteristics

Protocol: it is defined by CCIR 342 and 242 and allows the division of the link in4 transmission channels, characters and bits interleaved.

Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speeds: 96, 192 bauds

Main use: military and diplomatic traffic, formerly international telexcircuits.

RadioRaft particulars: characters have a normal or reversed polarity. Thepolarity indicator in hexadecimal indicates the polarity of the 16 latest receivedcharacters (for more details see 'The first screen line' in the maindocumentation).
The bits patterns are defined by the CCIR but some stations use different patterns.RadioRaft decode all of them.
In CCIR-342, the pattern is 1D1D (1717 with reversed shift).
In CCIR-242, 5555.

Arq-m4 options

This menu allows you to select the channel. You can select 1 of 4 channels, named A toD.
You can also see the traffic of both channels A and C, or B and D.

The choice 'All' allows to simultaneously view the 4 channels: it isinteresting to see if there is traffic without having to switch from one channel toanother. In this case the channels being character by character interleaved, it isdifficult to have a clear text, except if the traffic is transmitted in only one channel,while filling characters are transmitted in the others.

ARQ-N

Protocol: all characters are transmitted consecutively with the same polarity. Arepetition consists of the RQ character followed by 3 repeated characters.

Code: ARQ-E, 35 characters set, 7 bit words. 32 characters are formed by: 1 bit(0), 5 bits of the Baudot code and 1 odd parity bit for the detection of errors. 3supplementary characters are added (RQ and synchronization alpha and beta).

Current speed: 96 bauds

Current modulation: FSK

The polarity indicator is always 0000 (or FFFF if the shift is reversed).

POL-ARQ

Protocol: all characters are transmitted consecutively with the same polarity. Arepetition consists of the RQ character followed by 4 repeated characters.

Code: CCIR-476-4, 35 characters set, 7 bit words, 4 of which are always set to 1for the detection of errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK

Main use: diplomatic traffic

Some stations use a similar mode at 50 bauds. RadioRaft can decode itbut messages are always encrypted.

FEC MODES

These modes are used for broadcasting (e.g. transmission from a station tothe destination of one or several others, with protection against errors: FEC = ForwardError Correction).

AUTOSPEC

Protocol: characters are transmitted consecutively.

Code: Bauer code, 32 character set, 10 bit words (5 bits like ITA2 and 5 bitsfor the error detection and correction by a Hamming code).

Standard speeds: 62.3, 68.5, 102.6 and 137 Bauds.

Current modulation: FSK

CIS11

Protocol: characters are transmitted consecutively.

Code: 11 bit words, 32 characters set (5 bits of the Baudot code, 2synchronization bits and 4 bits for the error detection and correction by a Hamming code).

Current speeds: 75, 100 bauds.

Current modulation: FSK

Main use: aeronautical weather report from eastern Europe.

DGPS

Dgsp characteristics

Protocol: transmission of frames of codewords. The number of words in a framedepends on the message type and is variable in the same type, not exceeding 33.
The first codeword contains an 8 bits preamble, the message type (6 bits) and the stationId (10 bits).
The second codeword gives the 'Modified Z-count' (13 bits) which is the starttime of the next frame preamble, the sequence number (3 bits), the length of the frame (5bits) which is the number of codewords following this one and the station health (3 bits).

The 2 first codewords are common to all messages. The meaning of the next ones dependson the message type.

Code: 30 bit words:

• 24 data bits
• 6 bits for the CRC (cyclic redundant checksum), based on a polynomial code that allows error detection.

Current speeds: 100, 200 bauds. Other rates are also possible but not used.

Current modulation: MSK

Main use: worldwide transmissions of corrections to improve the accuracy of datareceived from GPS devices. The transmitters are located on the costs and intended to themaritime service. They transmit in the hectometric band around 300 Khz, with a rangearound 100-200 Kms.

RadioRaft particulars:

• A real MSK demodulation would require the receiver passes audio frequencies as low as 100 hz. The most of the receivers doesn't permit it. So RadioRaft demodulates DGPS by using the ordinary FSK demodulation routine.
  IMPORTANT: tune preferably your receiver to low audio frequencies around 300-800 Hz to get the best results. It is due to the very low shift used by MSK (50 hz at 100 bauds).
• RadioRaft decodes each field of the 2 first words which are common to all messages and give the identity of the station. The next words are displayed as 3 hex data bytes. Nevertheless RadioRaft decodes the whole messages 3 (reference station parameters), 5 (satellite constellation health), 7 (station almanach) and 16 (Ascii plain text). The occurence of these messages depend on the stations. Messages 16 are rare.
• MSK is very sensitive to noise and interferences. Use narrow filter with your receiver.

Dgsp messages display

Refer to recommendation ITU-R M.823 to interpret the different fields. Herethey are in brief:

• First line:

MSG xx Station463 Z-Time 37:4.2 Sequence:0 Length:12 Health:0

MSG: xx is the message type
Station: reference station number
Z-time: modified Z-count, time at which the corrections are computed in unitof 0.6 sec. See the options.
Sequence: sequence number (0-7), increments on each frame
Length: frame length, number of words following this one (0-31)
Health: station health (0-7)

• Other lines:

  • All messages but 3, 5, 7, 16, data are displayed as hex values:

Data: 012345 6789AB 1A2B3C..

• Message 3 (reference station parameters, coordinates according to WGS84 format):

Station coordinates (mtrs): X=4296717.12 Y= -263398.80 Z= 4690668.64

• Message 5 (satellite constellation health):

Satellite 23 IOD:0 Datahealthy Sat S/N not tracked Sat healthy
No new IOD Loss of satellite warning in (mn): 35

For each satellite:

Satellite number
IOD: Issue Of Data
Data healthy (or unhealthy)
Sat S/N not tracked (otherwise the signal to noise ratio is given inDb(Hz))
Sat healthy (consider sat healthy even if data unhealthy)
No new IOD (or New IOD soon)
Loss of satellite.. if scheduled, time remaining before loss

• Message 7 (station almanach):

Position: 47°38'48.1' North 3°30'36.0'West
Range: 170 Km Frequency: 298.0 KhzR/beacon operation normal
Tx.Id: 332 100 Bauds MSK synchronous No added coding

For each beacon in the almanach:

Position: lattitude and longitude of the station
Range: beacon service range
Frequency: beacon frequency
R/beacon operation normal: health of the beacon as plain text
Tx.Id: transmit station number. Don't confuse with 'referencestation number'.
100 bauds: data rate of the beacon
MSK: the modulation the beacon is using (also FSK)
Synchronous: synchro type (also asynchronous)
No added coding: broadcast coding (also 'FEC coding')

Messages 16, ASCII text information follows this header.

Dgsp options

Stop on error

If an error is received in a word and this option is set, the next words are notdisplayed. RadioRaft is waiting for the next frame.

Display hex data

You may avoid to display hex data by disabling this option. Only the 2 first words in aframe are displayed.

Z-count in time format

Option by default: the time is displayed in the MM:SS.t format (t = tenths of second).If this option is not set, the time is displayed as received, i.e. in multiple of 0.6 sec.This is the time elapsed since the previous round hour, at which the corrections arecomputed.

FEC-A

Protocol: transmission of 2 channels, bits interleaved. The characters of a messageare transmitted in one of the 2 channels and the bits of an error correcting cyclic codein the second one.

Code: FEC-A, 7 bit words, 34 characters set. 32 characters are formed by: 1 bit(0), 5 bits of the Baudot code and 1 even parity bit for the detection of errors. 2supplementary characters are added (RQ and beta).

Current speeds: 96, 144, 192 bauds

Current modulation: FSK

Main use: military and diplomatic traffic, news.

RadioRaft particular: RadioRaft does not provide error correction.

HNG-FEC

Hng-fec characteristics

Protocol: each bit of a character is spread on 64 bits and is interleaved with thebits of other characters.

Code: 15 bit words for 5 effective data bits (redundancy for the errorcorrection), 32 characters set.

Current speed: 100.05 Bauds.

Current modulation: FSK

Main use: diplomatic traffic.

RadioRaft particular: if the shift is reversed, the decoding will be correctbecause a reversed code word is also a valid code word. On the other hand erroneouscharacters will be displayed. To alleviate this difficulty, RadioRaft attempts to find theright shift by understanding some transmitted characters. This needs time, and even failsif the transmitted message is encrypted or if it contains some particular sequences.

Hng-fec options

Auto-shift (enabled by default)

To enable/disable the automatic detection of the shift (enabled by default).

Reversed shift

Clicking on 'Reversed shift' inhibits the automatic shift detection, and thenswitches to the normal or reversed shift.

POCSAG

Pocsag characteristics

Protocol: transmission of lots of one synchronization word followed by 16 codewordscontaining addresses and numerical or alphanumerical data.

Code: 32 bit words:

• 1 bit for indicating the word is an address codeword (1) or a message codeword (0)
• 18 address bits and 2 function bits, or 20 data bits
• 10 bits for the CRC (cyclic redundant checksum), a polynomial code that allows error detection and/or correction.
• 1 even parity bit for the whole codeword

Bits for data can contain numerics or alphanumerics, depending on the pager service.

Current speeds: 512, 600, 1200 and 2400 Bauds.

Modulation: DFSK at +/- 4.5 Khz.
IMPORTANT:As in DFSK the data signal directly modulates the HF carrier, youwould need to connect directly the interface to the FM discriminator of your receiver,without capacitor. This permits to keep the continuous component of the data signal whenlong series of 0 or 1 are transmitted.
Another simpler way is to use the classical interface connected to the speacker output buthaving a hysteresis adjustment. It allows to maintain the right level when the data signalis constant. In the Diagram of the interface shown in theRadioRaft user's manual, the resistances R2/R3 permit to adjust the hysteresis.
You must adjust the signal level just above the threshold of hysteresis.
If you are using an ordinary interface, you will not be able to receive POCSAGexcept if your receiver passes audio frequencies below 50 Hz which is a bit out ofordinary.

RadioRaft particular: RadioRaft is able to correct 2 errors per word even in thesynchronization word.

Main use: POCSAG is used on VHF and UHF for message transmissions topagers.

Pocsag message display

RadioRaft displays the address of the pager in octal, followed by the service number(0: numerics, 3: alphanumerics), then the message. Examples:

6154773-0| 003312345678
7610321-3| Midnight! It's time you go home. Mummy.

Pocsag options

Checksum (enabled by default)

The display of messages is interrupted when a CRC error is encountered in a codewordand the error cannot be corrected.

Error correction (enabled by default)

RadioRaft corrects possible errors. RadioRaft can correct 2 erroneous bits by codewordeven for the synchronization word.

End of message on {nul} (enabled by default)

The reception is stopped if an ASCII character NUL is encountered.

All messages (enabled by default)

The options 'All messages', 'Alphanumerics', 'Text only'and 'Numerics' are mutually exclusive.
If 'All messages' is active, RadioRaft displays all messages (numerics oralphanumerics).

Alphanumerics

RadioRaft displays only alphanumerical messages.

Text only

RadioRaft displays only alphanumerical messages that contain at least one letter.
The option permits to cancel pure numerical messages that are transmitted toalphanumerical pagers.

Numerics

RadioRaft displays only numerical messages.

Disable empty messages

RadioRaft doesn't display messages without data.

RUM-FEC

Rum-fec characteristics

Protocol: each bit of a character is spread on 129 bits and is interleaved with thebits of other characters.

Code: 16 bit words for 5 effective data bits (redundancy for the errorcorrection), 34 characters set.

Current speeds: 164.5 and 218.3 Bauds.

Current modulation: FSK

Main use: diplomatic traffic.

RadioRaft particular: if the shift is reversed, the decoding will be correctbecause a reversed code word is also a valid code word. On the other hand erroneouscharacters will be displayed. To alleviate this difficulty, RadioRaft attempts to find theright shift by understanding some transmitted characters. This needs time, and even failsif the transmitted message is encrypted, or if it contains some particular sequences.

Due to the wide spread, the scanning needs at least 16 seconds of signal beforeRadioRaft synchronizes.

Rum-fec options

Auto-shift (enabled by default)

To enable/disable the automatic detection of the shift.

Reversed shift

Clicking on 'Reversed shift' inhibits the automatic shift detection, and thenswitches to the normal or reversed shift.

SITOR-B, NAVTEX

The SITOR mode B is also known by radioamateurs as AMTOR mode B or TOR/FEC.

Sitor-B characteristics

Protocol: CCIR Recommendation 476-4. Transmission of 2 channels, charactersinterleaved. One channel transmits the same message as the second one but with a delay of4 characters.
Error correction: if a character in the first channel is erroneous, it is taken from thesecond channel.

Code: CCIR 476-4, 7 bit words, 4 of which are always set to 1 for the detectionof errors if this criterion is not verified.

Current speed: 100 bauds

Current modulation: FSK

Main use: weather reports, warnings to navigators and call lists for ships,radioamateurs.

NAVTEX

NAVTEX is not a mode but a particular SITOR-B transmission of messages for the urgentwarnings to navigators, on 518 kHz.
The headers of such messages are formatted and the rest as plain text.
RadioRaft displays the headers as they are (no decoding of the numerical fields) and themessage body as plain text.

SPREAD

Protocol: each character is spread on 11, 21 or 51 bits, each bit of a character isinterleaved with the bits of other characters.

Code: Bauer code, 10 bit words (5 bits like ITA2 and 5 bits for the errorcorrection by a Hamming code), 32 characters set.

Standard speeds: 62.3, 68.5, 102.6, 137 and 218.3 Bauds.

Current modulation: FSK

Main use: formerly diplomatic trafic

RadioRaft particular: the modes are named SPREADx where x=11, 21 or 51 dependingon the spread.

1382

1382 characteristics

Protocol: transmission of a bit pattern for the bit phasing, then a 32 bitsynchronisation word followed by the codewords

Code: 64 bit words containing 48 data bits and 12 bits for the error detectionby a cyclic code.
The 48 data bits may also include a convolutional code for the error correction (notimplemented in RadioRaft and not used by the pagers).

Standard speed: 1200 Bauds.

Current modulation: MSK 1200/1800 Hz. Warning: this modulation is verysensitive to noise or interferences.

Main use: used in France to transmit messages to pagers in emergency services(similar to Pocsag). 1382 is also used to pass signalling in private radiotelephonenetworks.

RadioRaft particular: 1382 is the reference of the protocol. RadioRaft decodesonly the version of 1382 used in emergency services, particularly by firemen.

1382 Options

Start on {Stx}

Option by default : no text is displayed until ASCII code 02 (STX) is received.

Stop on {Etx}

Option by default : text is not displayed after receiving ASCII code 03 (ETX).

Stop on error

RadioRaft stops the display after an error is encountered. This option is disabled bydefault.

PACKET MODES

These modes don't need that transmitting and receiving stations aresynchronized. A packet can be sent at any time.

ACARS-VHF

Acars-vhf characteristics

Protocol: Refer to ARINC characteristic 597-4. Packets contain:

• 'Pre-key' 16 characters of data at 1
• Bit sync: 2 ASCII characters '+' and '*' to enable bit ambiguity resolution to be accomplished
• Character sync: ASCII control code SYN to establish character synchronization
• Start of heading: ASCII character SOH
• Mode: 1 character. Refer to ARINC Characteristic 597-4.
• Address: 7 characters. Aircraft identification or aircraft or filght number registration mark
• Acknowledgement: ASCII character ACK or NAK
• Label: 2 characters to identify message routine and type.
• Block: Uplink block identifier (1 character)
• Text: ASCII character STX followed by the text of the message. Text is not always present in a message.
• Suffix: ASCII character ETX.
• BCS: block check sequence. Polynomanial code for the detection of errors (2 bytes).
• BCS suffix: ASCII character ETB

Code: ASCII 7 bits + 1 even parity bit.

Current speed: 2400 bauds

Modulation on VHF: FFSK 1200/2400 Hz. The presence of 1200 Hz indicates abit change from the previous value, the presence of 2400 Hz indicates that there is no bitchange.

Particular: you need a receiver with a good audio quality to decode ACARSmessages, specially flat frequency and phase response.
On HF the modulation is very different. RadioRaft doesn't demodulate ACARS HFmodulation. It doesn't decode ACARS-HF.

Use: earth/planes aeronautical information exchange.

Acars-vhf messages display

RadioRaft doesn't decode data fields of the Acars protocol. It displays the field namesfollowed by their contents as they are.

For example:

----Mode:J---Address:.F-ABCD---ACK:{NAK}---Label:Q3---Mode:A---Block:3
Text: Please book 2 seats tonight at Moulin Rouge. Landing Paris soon.

See above the ACARS protocol for the meaning of the fields. Text is displayed as plaintext but it can appear unclear when it is formatted for technical information exchange.

Acars-vhf option

Checksum (enabled by default): the checksum control of the whole frame is active.When disabled, frame including errors are nevertheless displayed as well as characterswith parity error.
In normal functioning, 'Cheksum' must be enabled.

GMDSS-DSC

Gmdss-dsc characteristics

Protocol: ITU-R M.493. Characters are transmitted by packets with an error-checkcharacter for the entire sequence. Each character is transmitted twice in a time-spreadmode. The repetition of a character occurs 4 character after its first transmission, as inSITOR-B.

Code: 10 bits words allowing error detection, 128 characters set. Symbols 0 to 99 are used to transmit numerical values. The meaning of characters 100 to127 depend on their position in the message and on the message format.

Current speeds: 100 bauds (hectometric and shortwaves), 1200 bauds (VHF).

Current modulation: FSK. HF: shift is 170 Hz. VHF: shift is 800 Hz(Mark/space: 1300/2100 Hz).

Main use: DSC is the selective calling mode of the Global Maritime Distress and Safety System.

IMPORTANT RadioRaft particular: RadioRaft decode all DSC messages except: distressrelay, distress relay acknowledgement and selective call to a group of ships ina particular geographic area. It decodes distress calls.

Gmdss-dsc messages display

Examples:

SelCall>Address: 123-456789 Category:Safety
Self-Id: 987-654321
Message: F3E/G3E simplex telephone {RQ}

SelCall>Address: 123-456789 Category:Routine
Self-Id: 987-654321
Message: None
Rx frequency: 16419.5 Tx frequency:16419.1 {BQ}

<<>>
Self-Id: 123-456789
Nature: Collision
Coordinates (lat/long): NE 04°29' 033°15' Time: 12:47
Message: J3E telephone

Refer to recommendation ITU-R M.493 to interpret the different fields.

In brief:
The message begins with the format specifier of the message as plain text(SelCall, Distress call..)
Address: 9 digits address of the ship or 10 digits address of a group of ships
Category: category of the message (distress, urgency, safety, ship's business,routine)
Self-Id: self-identification of the calling station. It is the maritime mobile serviceidentity (MMSI)
Message: message as plain text (coordinates, frequencies or channels, type of communication..)
{BQ} or {RQ}: RQ if the call requires acknoledgement, BQ if it is an answerto a call with RQ, nothing in other cases.

Nature: nature of the distress, in distress messages only.
Coordinates: position at the time of the distress call.
Time: time of the distress call.

RadioRaft adds {Checksum error} if the message contains at least an erroneouscharacter.

PACKET (Packet radio)

Packet characteristics

Protocol: AX25 (X25 variant protocol). Packet frames contain:

• 1 or several 'flag' byte
• 7 bytes for the destination address including 1 SSID byte (Secondary Station IDentifier)
• 7 bytes for the source address including 1 SSID byte
• 0 up to 8 repeater addresses of 7 bytes each including 1 SSID byte
• 1 control byte
• 1 PID byte (protocol identifier)
• none or several data bytes
• 2 bytes for the CRC, based on a polynomial code.
• 1 'flag' byte

Code: none. Any data types can be placed in the data bytes. When text istransmitted, ASCII is used with the 8th bit at 0.

Current speeds: 300 (shortwaves only), 1200, 2400, 9600 bauds

Current modulation: FSK (except above 2400 bauds)

Packet messages display

For each PACKET frame, RadioRaft displays the call signs with the SSID of the stationof destination, of source and of possible repeaters, then the control byte and the PID inhexadecimal format. Finally the possible information text of the frame is displayed. Apacket appears as follows:

A3XYZ -0

(for ex. a message from F6FLT to A3XYZ via EA8XYZ, with the control byte = 03, and thePID = 15). Any information type can be transmitted in PACKET (pictures, computer programs,text or sound files..).

The ASCII code is generally used for text transmissions. RadioRaft displays theinformation content of a PACKET frame with the 8-bit ASCII code. If you view frames ofinformation containing a program or a picture, codes of the file will be interpreted asASCII characters and displayed as cabalistic signs!

Packet options

Cheksum (enabled by default)

The checksum control is active. If disabled, frames including errors are neverthelessdisplayed. In normal functioning, 'Cheksum' must be enabled.

Whole packet (enabled by default)

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Options 'Whole packet', 'Data only', 'Address only' aremutually exclusive.
In normal functioning, 'Whole packet' is enabled, and therefore all frame dataare displayed, with addresses.

Data only

Only call signs of destination, source and possible repeater stations with their SSIDwill be displayed. Information data of the frames are not displayed.

Address only

Only information data of the frames will be displayed. In association with the filter,this option allows to follow the traffic from or to a particular station.

Destination filter, Source filter

When you select 'Destination filter' and/or 'Source filter',displayed messages are only those of a particular source station to a particulardestination station, of which you specify the call signs (during this selection, RadioRaftpositions automatically the cursor at the beginning of the field for the text input).

If the 2 filters are active at the same time, only messages having both destination andsource call signs as addresses will be displayed.

Note - you must enter the call signs in upper case. If you indicate no call sign, nomore packets will be displayed because RadioRaft will be expecting call signs with 6spaces!

In normal functioning 'Destination filter' and 'Source filter' aredisabled. At any time you can enable or disable the filtering while the call signs remain.

OTHER MODES

BaudMeter

The BaudMeter measures the speed of synchronous modes up to 300 bauds within 0.5 baud.Speeds of asynchronous modes are generally not found, except those having 1 start bit, 5data bits and 1 or more stop bits as Baudot. For other asynchronous modes, use the'DIGIT' mode.

The speed is in fact the 'modulation rate'. A small window appears anddisplays the last measurement when it is available.

You can also use the 'DIGIT' mode to measure the modulation rate (see thismode).

BaudMeter option:

Synchronous mode (enabled by default): you must disable thisoption to measure speed of asynchronous transmission as Baudot. Only speed of asynchronousmodes with 1 start bit, 5 data bits and 1 or more stop bits can be measured.
To measure any other asynchronous modes, see the option 'Synchronous' of theDIGIT mode.

CW

This is the well-known Morse code.

WARNING: If you are using a MODEM, check that the 'shift' specified in the'Options' menu is right. The polarity indicator must indicate 1 when the signalis present, 0 when there is no signal.

With the interface, the shift must be normal (not marked).

Protocol: none.

Code: Morse (invented by Samuel Morse)

Speed: any. RadioRaft adapts itself automatically to the transmission speed. Thespeed is displayed in Bauds.

You can fix the speed by disabling the 'scan-baud' or by entering a value inthe baud input field (menu 'Bauds').

Usually, the CW speed is in Wpm, words per minute, but this is imprecise. The Morsereference element is the duration of a dot. The 'CW Baud' is therefore theopposite of this duration. For ex: 20 Bauds correspond to a dot duration of 1/20=50 ms(approximately 22 Wpm).

Modulation: AM, sometimes FSK.

RadioRaft perfectly decodes automatic transmissions in this mode, and 'does whatit can' for manual transmissions by operator: most operators have indeed a veryconsistent send rate, with the main default to paste letters together. In these conditionsonly a trained human brain can distinguish the meaning of --.--.. between:

QTH (--.- - ..) or QNS (--.- -. ..) or GT6 (--. - -..) or ..

DIGIT

Digit characteristics

This mode is unique to RadioRaft. It allows you to view a transmission bit-by-bit, in abinary or hexadecimal format, and to measure its speed. The bits are grouped in words tofacilitate viewing. When you start the program, the display is initialized for 7 bitswords, and 8 words rows (see the options about this subject).

There is no correlation between these words and any character codes that would bereceived: for example in the case of the reception of a CCIR-476 code, the 7 bits of acharacter can be in between 2 words. 'DIGIT' ignores the nature of thetransmission. Keys F9/F10 allow to shift left or right the bits display.

'DIGIT' is essentially a tool for analysis, to show exactly what is received.This tool can also be used to decode unknown modes. It requires the knowledge of thetransmission speed. DIGIT automatically seeks the valid speed.

Digit does not display anything as long as it has not found the speed. If the scanningof the speed fails, you have to select it manually in the 'Bauds' menu. Thatforces the display of the received bits.

For the asynchronous modes, see below the option 'Synchronous mode'.

Pocsag Paging Transmitter

Digit options

Words size

This option sets the number of bits by word (1 to 252). The display in hexadecimalformat does not allow for exceeding 16-bit words. Above 16-bit words, only the last 16bits are processed. Click on the digits in the word size field: a left click increases thevalue, a right click decreases it. You can also press + or -.

Words by rows

This option sets the number of words in a row (1 to 32).

Code..

This command opens a menu for choosing the translation code you can use to display thecharacter corresponding to the last x bits (x is the number of bits by character of thecode. If x is minus than the size of words, only the last x bits of words are taken forthe translation.

For ex. RY transmitted in Baudot:

1001010 R|1010101 Y|1001010 R|1010101 Y..

For each word, the first bit 1 is a stop bit of the previous character. The following 0is the start bit of the character. The next 5 bits (01010 or 10101) are the baudot code ofthe character, used for the translation.

The menu 'Code..' permits also to:

Invert H/L bits in words

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It inverts the bits of high and low order before the translation.

Reverse 0/1 on error

It allows you to reverse all the bits and resume the translation, after a firsttranslation fails with an erroneous character (e.g. ratio 4/7 unchecked in CCIR-342 or476, or word not found in the code set). This allows you to display modes that usecharacters reversals (ARQ-M, ARQ-E).

Acars type

With FSK or FFSK modulation, a bit at 0 corresponds to the lower frequency, a bit at 1to the higher.

If you activate this option, the low frequency indicates a bit change from the previousbit, the high frequency indicates that there is no change.

Synchronous mode

You must disable this option (enabled by default) to view bit-by-bit an asynchronoustransmission or to measure its speed.

In this case the knowledge of the number of bits by character is necessary: you mustset it in the option 'Words size'. If you want to view a Baudot transmission forexample, set 'Words size' to 7 (=1 start bit + 5 bits of the Baudot code + 1stop bit). The speed of the transmission cannot be found if the word size is not properlyset.

Stop on missing signal

The bits display will be stopped if no data signal transition is encountered within thetime fixed in the menu 'Options/Strategy/Time' (4 sec by default).

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Delta

'Delta' allows you to display the transitions from the input signal insteadof the state of bits (an absence of transition corresponds to 0, a transition to 1). Forexample enable this option to view a frame of an AX25 packet.

Parity

'Parity' allows you to display the parity of the last n received bits, nbeing the number of bits by word.

Reverse 0/1

Reverses the display 0/1 in 1/0.

Even / Odd bits

To enable 'odd or even bit' forces the display of only one by two bit of oddor even rank, which allows you to view one channel of a transmission with interleavedbits, like the ARQ-M4 or FEC-A modes.

Binary / Hexadecimal

The display is in binary or hexadecimal format. The hexadecimal is limited to 16-bitwords.

LIST OF SOME FREQUENCIES

For more informations about utility radio stations (list of frequencies, transmissionmodes..), please refer to the following guides and publishers

Back to the summary

GLOSSARY

• ACARS: Aircraft Communications Addressing and Reporting System
• AM: amplitude modulation
• ARINC: Aeronautical Radio, INC, 2551 Riva Road, Annapolis, MAryland 21401, USA
• ARQ: Automatic Repetition reQuest
• BPS: Bit Per Second, e.g. real traffic flow (data rate).
• BAUD: unit for the modulation rate, e.g. the opposite of the duration of the smallest transmitted element (for example, 50bauds corresponds to 20 ms elements). Not equal to 'BPS', because some types of modulation (for example MFSK) allows transmission of several bits simultaneously.
  The unit 'baud' comes from the name of the French engineer Baudot who created the first 5 elements telegraph in the 19th century.
• CW: Continuous Wave
• DFSK: Direct Frequency Shift Keying (no subcarrier)
• DGPS: Differential GPS
• DSC: Digital Selective-Calling. In GMDSS, mode specified by recommendation ITU-R M.493-6.
• FEC: Forward Error Correction
• FFSK: Fast FSK
• FSK: Frequency Shift Keying
• GMDSS: Global Maritime Distress and Safety System
• GPS: Global Positioning System (or Satellite)
• INTERFACE: circuit transforming the audio signal from the speaker into the same but square signal compatible with the electric levels RS232 of serial COM ports.
• LSB: Low Side Band
• MARK: data level 1 of a signal corresponding to the lower frequency
• MMSI: Maritime Mobile Service Identity
• MODEM: modulator/demodulator (only the demodulator function of a modem is needed for RadioRaft).
• MODULATION: transformation of a data signal into a signal compatible with a transmission circuit. The process makes the data signal varies one or several parameters (amplitude, phase, frequency) of one or several 'carriers' that form the transmitted signal.
• MSK: Minimum Shift Keying
• POCSAG: Post Office Code Standardization Advisory Group
• RQ: repetition request
• SHIFT: frequency displacement of FSK signal within the lower and the higher frequencies
• SPACE: data level 0 of a signal corresponding to the highter frequency
• SYNCHRONIZATION: indication of a RadioRaft state in which a right bits pattern, characteristic of a mode, has been detected. RadioRaft is phasing with it.
• TOR: Telex Over Radio.
• USB: Up Side Band.
• 1382: ST/PAA/TPA/1382, specification of a data and signalling transmission system from the 'Centre National d'Etudes de Telecommunications' of France Telecom.

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