RADIORAFT 3.21
RADIO SIGNAL DECODER SOFTWARE
Copyright (c) 1996-2002 by Francois
Guillet
All rights reserved.
MODES AND OPTIONS USER'S GUIDE
| ACARS-VHF | ARQ-E | ARQ-E3 | ARQ-M2 (+si-fec) | ARQ-M4 |
| ARQ-N | ARQ-6/90 | ARQ-6/98 | ASCII | AUTOSPEC |
| BAUDOT | CIS11 | CW (Morse) | DGPS | DUP-ARQ (Artrac) |
| FEC-A (FEC-1000) | GMDSS-DSC | HNG-FEC | PACKET (Ax25) | PACTOR-I |
| POCSAG (1) | POL-ARQ | RUM-FEC | SI-ARQ (Arq-s) | SITOR-A (Amtor-A) |
| SITOR-B (Amtor-B) | SPREAD (11, 21, 51) | SWED-ARQ | UOSAT Oscar-11 | 1382 |
| BaudMeter | DIGIT |
(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. The
command "Options..." in this menu allows you to access options available for the
current mode.
The key F6 permits you to access directly to the menu "options".
These modes use a start bit (0) at the beginning of each character, and one or several stop bits (1) at the end. Each character can be transmitted at any time. The stop bit has duration of 1 or 1.5 times the duration of other bits. Transmissions of this type are numerous, especially those using the Baudot code.
Nevertheless many stations use a stop bit of normal duration and transmit characters consecutively, resulting in a quasi-synchronous transmission.
Modes of this type that RadioRaft decodes are:
The names of ASCII modes in RadioRaft are:
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). 8 bit characters are also sometimes used (256 characters set).
Current speeds: 110, 200, 300, 600, 1200 bauds
Current modulation: FSK
This option enables or disables the parity check.
If it is disabled, erroneous characters are displayed as they would have no parity error. 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 (ASCII 126, ~).
This option has no effect on ASCII modes without parity.
RadioRaft supposes that characters are transmitted consecutively with no delay between following characters, resulting in a quasi-synchronous transmission. This improves the decoding.
You must disable this option with pure asynchronous transmissions (for ex. manual transmission with delay between characters).
Inverts the order of low and high bits in the ASCII code. Generally you don't need to enable this option because ASCII transmissions send always the low bit the first, what RadioRaft is expecting.
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.
Same as ASCII. UOSAT data transmissions send ASCII text with or without a parity bit. By default RadioRaft doesn't check the parity.
The names of Baudot modes in RadioRaft are:
This mode is sometimes named RTTY.
Protocol: 1 start bit (0), 1 codeword, 1 or several stop bit (1). Generally the stop 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 the most 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 5
elements telegraph (1 element for each finger, a character was coded with the hand!)
These options are available only in manual mode (by clicking on "Manual" in the main menu or hitting key F4) and in the pure Baudot mode (not available in Baudot-1, Baudot-2, Baudot1-1).
RadioRaft finds automatically the right shift
Clicking on "Reversed shift" inhibits the automatic shift detection, and then switches to the normal or reversed shift, which can improve the decoding if the signal is disturbed.
These modes are only used in bilateral transmissions. A station transmits the text in blocks of several characters, then switches to reception and waits for an acknowledgment of 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 particular characters sequence. The 2 stations are generally on the same frequency, but it is not a rule (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 between the 2 stations, repetitions can indeed be very frequent, up to several minutes). However an option allows you to view the repetitions and the special characters (menu "Display/Display control codes").
Modes of this type are:
Protocol: transmission of blocks of 6 characters. Duration of a block 210 ms, time between 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 1 for the detection of errors if this criterion is not verified.
Current speed: 200 bauds
Current modulation: FSK
Main use: diplomatic traffic
Protocol: transmission of 32 bit blocks containing:
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
RadioRaft decodes only PACTOR version I.
Protocol: transmission a phasing byte followed by 96 or 192 bits block containing:
Code: none. Any type of data can be placed in the data bytes. When text is transmitted, 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
If you disable this option (enabled by default), RadioRaft will not check the CRC and could display blocks with errors.
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.
RadioRaft displays in this field the CRC it detects. You can also enter yourself the CRC. This permits to reduce the time to synchronize or to prevent RadioRaft from decoding other Pactor mode (Auto CRC must be set).
Protocol: transmission of blocks of 4, 5, 6 or 7 characters with alternate polarities except in case of repetition. The time between 2 blocks is equal to the time of a block.
Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1 for 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, 6
or 7 depending on the block size.
The masking of repetitions, contrarily to SITOR-A, never entails a loss of text.
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 1 for 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 considers
it is a block repetition, and does not display the second block. This criterion of
decision that there is repetition can sometimes entail the loss of text (for ex. during
highlighting, several blocks "---" are transmitted, and RadioRaft wrongly
considers there are repetitions. Nevertheless this event is rare.
RadioRaft identifies the transmission of a selective call and display the callsign
following by the text: {Selcall}.
RadioRaft doesn't not translate the 4 letters callsign in digits for the maritime station
identification.
RadioRaft doesn't support the new CCIR Recommendation 625-2 for the 9 digits ship station
identification.
The ear can easily identify this mode: it sounds like the chirping of the cricket.
Protocol: transmission of blocks of 3, 9 or 22 characters.
Code: CCIR 476-4, 35 characters set, 7 bit words, 4 of which are always set to 1 for 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 automatic
according to the link conditions. RadioRaft detects automatically the change of block
sizes.
When block is 3 characters length, this mode is strictly identical with SITOR-A. RadioRaft
decodes the 3 characters block of the SWED-ARQ mode as the SITOR-A mode, the only
difference being that a selcall is not identified.
Repetitions are canceled as in SITOR-A.
These modes are generally used for bilateral connections and need these stations have simultaneous transmission and reception on separate frequencies.
They are used for the military and diplomatic traffic and were used on international telex circuits. In case of bad links between the two stations, there are repetitions by cycles of 4, 5 or 8 characters.
As with ARQ semi-duplex modes, RadioRaft inhibits repetitions, except if the opposite option is set (menu "View/Display control codes").
Protocol: 3 or 7 erect characters follow 1 reversed character, and so on. In case of repetition, a special character RQ is transmitted. It is followed par 3 or 7 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. 3 supplementary 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 7777 if the shift is reversed.
Main use: military and diplomatic traffic
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 7 repeated characters.
Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1 for 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 1111 or respectively 7F7F or 7777 if the shift is reversed.
Protocol: CCIR 342 and 242. It allows the division of the link in 2 transmission channels, 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 1 for 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 indicates
the polarity of the 16 latest received characters (for more details see "The first
screen 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.
This menu allows you to select the channel. You can select 1 of 2 channels, named A and B.
The choice "All" allows to simultaneously view the 2 channels: it is
interesting to see if there is traffic without having to switch from one channel to
another. In this case 2 channels being character by character interleaved, you have not a
clear text, except if the traffic is transmitted on only one channel, while idle
characters are transmitted on the other one.
This mode is unusual. It is not implemented in RadioRaft as a full mode, but the ARQ-M2
RadioRaft 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.
Protocol: it is defined by CCIR 342 and 242 and allows the division of the link in 4 transmission channels, characters and bits interleaved.
Code: CCIR 342-3, 35 characters set, 7 bit words, 4 of which are always set to 1 for the detection of errors if this criterion is not verified.
Current speeds: 96, 192 bauds
Main use: military and diplomatic traffic, formerly international telex circuits.
RadioRaft particulars: characters have a normal or reversed polarity. The
polarity indicator in hexadecimal indicates the polarity of the 16 latest received
characters (for more details see "The first screen line" in the main
documentation).
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.
This menu allows you to select the channel. You can select 1 of 4 channels, named A to
D.
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 is interesting to see if there is traffic without having to switch from one channel to another. In this case the channels being character by character interleaved, it is difficult to have a clear text, except if the traffic is transmitted in only one channel, while filling characters are transmitted in the others.
Protocol: all characters are transmitted consecutively with the same polarity. A repetition 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. 3 supplementary 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).
Protocol: all characters are transmitted consecutively with the same polarity. A repetition 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 1 for 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 it but messages are always encrypted.
These modes are used for broadcasting (e.g. transmission from a station to the destination of one or several others, with protection against errors: FEC = Forward Error Correction).
Protocol: characters are transmitted consecutively.
Code: Bauer code, 32 character set, 10 bit words (5 bits like ITA2 and 5 bits for the error detection and correction by a Hamming code).
Standard speeds: 62.3, 68.5, 102.6 and 137 Bauds.
Current modulation: FSK
Protocol: characters are transmitted consecutively.
Code: 11 bit words, 32 characters set (5 bits of the Baudot code, 2 synchronization 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.
Protocol: transmission of frames of codewords. The number of words in a frame
depends 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 station
Id (10 bits).
The second codeword gives the "Modified Z-count" (13 bits) which is the start
time of the next frame preamble, the sequence number (3 bits), the length of the frame (5
bits) 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 depends on the message type.
Code: 30 bit words:
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 data received from GPS devices. The transmitters are located on the costs and intended to the maritime service. They transmit in the hectometric band around 300 Khz, with a range around 100-200 Kms.
RadioRaft particulars:
Refer to recommendation ITU-R M.823 to interpret the different fields. Here they are in brief:
MSG xx Station 463 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 unit
of 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)
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 Data
healthy 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 in
Db(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 Khz
R/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 "reference
station 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")
If an error is received in a word and this option is set, the next words are not displayed. RadioRaft is waiting for the next frame.
You may avoid to display hex data by disabling this option. Only the 2 first words in a frame are displayed.
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 are computed.
Protocol: transmission of 2 channels, bits interleaved. The characters of a message are transmitted in one of the 2 channels and the bits of an error correcting cyclic code in 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. 2 supplementary 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.
Protocol: each bit of a character is spread on 64 bits and is interleaved with the bits of other characters.
Code: 15 bit words for 5 effective data bits (redundancy for the error correction), 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 correct
because a reversed code word is also a valid code word. On the other hand erroneous
characters will be displayed. To alleviate this difficulty, RadioRaft attempts to find the
right shift by understanding some transmitted characters. This needs time, and even fails
if the transmitted message is encrypted or if it contains some particular sequences.
To enable/disable the automatic detection of the shift (enabled by default).
Clicking on "Reversed shift" inhibits the automatic shift detection, and then switches to the normal or reversed shift.
Protocol: transmission of lots of one synchronization word followed by 16 codewords containing addresses and numerical or alphanumerical data.
Code: 32 bit words:
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, you
would 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 when
long series of 0 or 1 are transmitted.
Another simpler way is to use the classical interface connected to the speacker output but
having a hysteresis adjustment. It allows to maintain the right level when the data signal
is constant. In the Diagram of the interface shown in the
RadioRaft 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 POCSAG
except if your receiver passes audio frequencies below 50 Hz which is a bit out of
ordinary.
RadioRaft particular: RadioRaft is able to correct 2 errors per word even in the synchronization word.
Main use: POCSAG is used on VHF and UHF for message transmissions to
pagers.
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.
The display of messages is interrupted when a CRC error is encountered in a codeword and the error cannot be corrected.
RadioRaft corrects possible errors. RadioRaft can correct 2 erroneous bits by codeword even for the synchronization word.
The reception is stopped if an ASCII character NUL is encountered.
The options "All messages", "Alphanumerics", "Text only"
and "Numerics" are mutually exclusive.
If "All messages" is active, RadioRaft displays all messages (numerics or
alphanumerics).
RadioRaft displays only alphanumerical messages.
RadioRaft displays only alphanumerical messages that contain at least one letter.
The option permits to cancel pure numerical messages that are transmitted to
alphanumerical pagers.
RadioRaft displays only numerical messages.
RadioRaft doesn't display messages without data.
Protocol: each bit of a character is spread on 129 bits and is interleaved with the bits of other characters.
Code: 16 bit words for 5 effective data bits (redundancy for the error correction), 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 correct because a reversed code word is also a valid code word. On the other hand erroneous characters will be displayed. To alleviate this difficulty, RadioRaft attempts to find the right shift by understanding some transmitted characters. This needs time, and even fails if 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 before
RadioRaft synchronizes.
To enable/disable the automatic detection of the shift.
Clicking on "Reversed shift" inhibits the automatic shift detection, and then switches to the normal or reversed shift.
The SITOR mode B is also known by radioamateurs as AMTOR mode B or TOR/FEC.
Protocol: CCIR Recommendation 476-4. Transmission of 2 channels, characters
interleaved. One channel transmits the same message as the second one but with a delay of
4 characters.
Error correction: if a character in the first channel is erroneous, it is taken from the
second channel.
Code: CCIR 476-4, 7 bit words, 4 of which are always set to 1 for the detection of 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 is not a mode but a particular SITOR-B transmission of messages for the urgent
warnings 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 the
message body as plain text.
Protocol: each character is spread on 11, 21 or 51 bits, each bit of a character is interleaved with the bits of other characters.
Code: Bauer code, 10 bit words (5 bits like ITA2 and 5 bits for the error correction 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 depending on the spread.
Protocol: transmission of a bit pattern for the bit phasing, then a 32 bit synchronisation word followed by the codewords
Code: 64 bit words containing 48 data bits and 12 bits for the error detection
by a cyclic code.
The 48 data bits may also include a convolutional code for the error correction (not
implemented in RadioRaft and not used by the pagers).
Standard speed: 1200 Bauds.
Current modulation: MSK 1200/1800 Hz. Warning: this modulation is very sensitive 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 radiotelephone networks.
RadioRaft particular: 1382 is the reference of the protocol. RadioRaft decodes
only the version of 1382 used in emergency services, particularly by firemen.
Start on {Stx}
Option by default : no text is displayed until ASCII code 02 (STX) is received.
Option by default : text is not displayed after receiving ASCII code 03 (ETX).
RadioRaft stops the display after an error is encountered. This option is disabled by default.
These modes don't need that transmitting and receiving stations are
synchronized. A packet can be sent at any time.
Protocol: Refer to ARINC characteristic 597-4. Packets contain:
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 a bit change from the previous value, the presence of 2400 Hz indicates that there is no bit change.
Particular: you need a receiver with a good audio quality to decode ACARS
messages, specially flat frequency and phase response.
On HF the modulation is very different. RadioRaft doesn't demodulate ACARS HF
modulation. It doesn't decode ACARS-HF.
Use: earth/planes aeronautical information exchange.
RadioRaft doesn't decode data fields of the Acars protocol. It displays the field names followed 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 plain text but it can appear unclear when it is formatted for technical information exchange.
Checksum (enabled by default): the checksum control of the whole frame is active.
When disabled, frame including errors are nevertheless displayed as well as characters
with parity error.
In normal functioning, "Cheksum" must be enabled.
Protocol: ITU-R M.493. Characters are transmitted by packets with an error-check character for the entire sequence. Each character is transmitted twice in a time-spread mode. The repetition of a character occurs 4 character after its first transmission, as in SITOR-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 to 127 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: distress
relay, distress relay acknowledgement and selective call to a group of ships in
a particular geographic area. It decodes distress calls.
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}
<<<DISTRESS CALL>>>
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 service
identity (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 answer
to 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 erroneous character.
Protocol: AX25 (X25 variant protocol). Packet frames contain:
Code: none. Any data types can be placed in the data bytes. When text is transmitted, 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)
For each PACKET frame, RadioRaft displays the call signs with the SSID of the station of destination, of source and of possible repeaters, then the control byte and the PID in hexadecimal format. Finally the possible information text of the frame is displayed. A packet appears as follows:
A3XYZ -0<F6FLT -0\EA8XYZ-1\03/15/ HI ELMER! WHAT'S UP DOC?
(for ex. a message from F6FLT to A3XYZ via EA8XYZ, with the control byte = 03, and the PID = 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 the information content of a PACKET frame with the 8-bit ASCII code. If you view frames of information containing a program or a picture, codes of the file will be interpreted as ASCII characters and displayed as cabalistic signs!
The checksum control is active. If disabled, frames including errors are nevertheless displayed. In normal functioning, "Cheksum" must be enabled.
Options "Whole packet", "Data only", "Address only" are
mutually exclusive.
In normal functioning, "Whole packet" is enabled, and therefore all frame data
are displayed, with addresses.
Only call signs of destination, source and possible repeater stations with their SSID will be displayed. Information data of the frames are not displayed.
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.
When you select "Destination filter" and/or "Source filter", displayed messages are only those of a particular source station to a particular destination station, of which you specify the call signs (during this selection, RadioRaft positions 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 and source call signs as addresses will be displayed.
Note - you must enter the call signs in upper case. If you indicate no call sign, no more packets will be displayed because RadioRaft will be expecting call signs with 6 spaces!
In normal functioning "Destination filter" and "Source filter" are disabled. At any time you can enable or disable the filtering while the call signs remain.
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, 5 data 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 and displays the last measurement when it is available.
You can also use the "DIGIT" mode to measure the modulation rate (see this mode).
BaudMeter option:
Synchronous mode (enabled by default): you must disable this
option to measure speed of asynchronous transmission as Baudot. Only speed of asynchronous
modes 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 the
DIGIT mode.
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 signal is 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. The speed is displayed in Bauds.
You can fix the speed by disabling the "scan-baud" or by entering a value in the baud input field (menu "Bauds").
Usually, the CW speed is in Wpm, words per minute, but this is imprecise. The Morse reference element is the duration of a dot. The "CW Baud" is therefore the opposite 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 what it can" for manual transmissions by operator: most operators have indeed a very consistent send rate, with the main default to paste letters together. In these conditions only a trained human brain can distinguish the meaning of --.--.... between:
QTH (--.- - ....) or QNS (--.- -. ...) or GT6 (--. - -....) or ...
This mode is unique to RadioRaft. It allows you to view a transmission bit-by-bit, in a binary or hexadecimal format, and to measure its speed. The bits are grouped in words to facilitate viewing. When you start the program, the display is initialized for 7 bits words, and 8 words rows (see the options about this subject).
There is no correlation between these words and any character codes that would be received: for example in the case of the reception of a CCIR-476 code, the 7 bits of a character can be in between 2 words. "DIGIT" ignores the nature of the transmission. 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 the transmission speed. DIGIT automatically seeks the valid speed.
Digit does not display anything as long as it has not found the speed. If the scanning of the speed fails, you have to select it manually in the "Bauds" menu. That forces the display of the received bits.
For the asynchronous modes, see below the option "Synchronous mode".
This option sets the number of bits by word (1 to 252). The display in hexadecimal format does not allow for exceeding 16-bit words. Above 16-bit words, only the last 16 bits are processed. Click on the digits in the word size field: a left click increases the value, a right click decreases it. You can also press + or -.
This option sets the number of words in a row (1 to 32).
This command opens a menu for choosing the translation code you can use to display the character corresponding to the last x bits (x is the number of bits by character of the code. If x is minus than the size of words, only the last x bits of words are taken for the 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 0 is the start bit of the character. The next 5 bits (01010 or 10101) are the baudot code of the character, used for the translation.
The menu "Code..." permits also to:
Invert H/L bits in words
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 first translation fails with an erroneous character (e.g. ratio 4/7 unchecked in CCIR-342 or 476, or word not found in the code set). This allows you to display modes that use characters reversals (ARQ-M, ARQ-E).
With FSK or FFSK modulation, a bit at 0 corresponds to the lower frequency, a bit at 1 to the higher.
If you activate this option, the low frequency indicates a bit change from the previous bit, the high frequency indicates that there is no change.
You must disable this option (enabled by default) to view bit-by-bit an asynchronous transmission or to measure its speed.
In this case the knowledge of the number of bits by character is necessary: you must set it in the option "Words size". If you want to view a Baudot transmission for example, set "Words size" to 7 (=1 start bit + 5 bits of the Baudot code + 1 stop bit). The speed of the transmission cannot be found if the word size is not properly set.
The bits display will be stopped if no data signal transition is encountered within the time fixed in the menu "Options/Strategy/Time" (4 sec by default).
"Delta" allows you to display the transitions from the input signal instead of the state of bits (an absence of transition corresponds to 0, a transition to 1). For example enable this option to view a frame of an AX25 packet.
"Parity" allows you to display the parity of the last n received bits, n being the number of bits by word.
Reverses the display 0/1 in 1/0.
To enable "odd or even bit" forces the display of only one by two bit of odd or even rank, which allows you to view one channel of a transmission with interleaved bits, like the ARQ-M4 or FEC-A modes.
The display is in binary or hexadecimal format. The hexadecimal is limited to 16-bit words.
List of frequencies in Khz. These on shortwaves were monitored in France, during 1997-2002. Modes are listed in alphabetical order and followed by the baud rate. Types of modulation are indicated when not FSK. The frequency is the mark except for modes with subcarrier where it is the carrier frequency (Acars, Pocsag...).
ACARS-VHF ACARS 2400 FFSK
Europe 131,725 131,825 131,525
USA 131,550 130,025 129,125
Asie/Pacific 131,550
Japon 131,450
Air Canada 131,475
ARQ-E
ARQ-E 72 5242.8 5420.0 5458.9 6981.9 13417.9 16226.0
ARQ-E 96 12150.0 13387.0 13848.5 13944.0 15861.6
ARQ-E 184.6 4768.9 6928.8 7613.9 9259.0 10625.8 13572.5
ARQ-E 192 5062.8 6928.8 6975.8 14626.7 14926.7 14959.7 16143.7
ARQ-E 288 (all encrypted) 10749.5 13073.4 13419.0 16312.4 16457.0
ARQ-E3
ARQ-E3 48 7831.6 7983.7 10917.7 14481.6
ARQ-E3 96 14438.2
ARQ-E3 100 10873.7 13444.2 16087.6 20633.6
ARQ-E3 192 6936.7 7606.5 9076.5 10103.5 10177.5 11110.5 12089.0 13543.5 14626.5 14959.5 14927.5 15926.5 15962.6 16077.5 16261.5 16324.5 17550.8 18042.6 18320.6 18503.7 19048.6 19646.6 20716.6 20813.6
ARQ-E3 200 11098.1 13465.1 14585.6 15636.6 16310.1 18435.6 18447.6 19063.6 19225.1
ARQ-M2
ARQ-M2 96 7596.0
ARQ-M2 200 3628.6 3832.5 4765.1 5397.6 7642.6 8050.1 8108.1 9907.6 10991.6 11518.1 13397.5 16125.1 16165.1 16193.2 19385.1 20805.1 20845.1 20865.1
ARQ6
ARQ6/90 200 16212.9 18526.9
ASCII
ASCII8-1 292 10164.0
ASCII8-1 300 1851.0 1897.4 1975.0 2021.0 3224.5
ASCI8-1-0 200 129.0 138.8 (DCF49)
ASCI8-2 600 (encrypted, ARQ protocols) 12203.0 12204.7 12207.2 14888.2
BAUDOT
Very numerous frequencies. Only some are listed below. In this sample, there are stations with 1, 1.5 and 2 stop bits.
BAUDOT 50 0147.0 4583.0 7646.0 10213.0 11080.0 11462.0 12186.0
BAUDOT 75 4489.0 6483.0 9130.0
BAUDOT 100 4569.8 9040.8
BAUDOT 150 6348.0 8099.0 10484.0 12134.0 12140.0 13933.0 14384.0 14779.0 14855.0 19365.0
BAUDOT 200 11459.9
BAUDOT-1-0 75 8568.1 (FUV)
DGPS
285 - 325 Khz band, channel spacing: 0.5 Khz.
DUP-ARQ
DUP-ARQ 125 12262.3 13875.2 15675.8
FEC-A
FEC-A 96 3826.3 6974.3 7916.0 7919.0 9361.9 13438.6 13570.8 15933.1 18704.2
FEC-A 144 9060.0 16204.0
FEC-A 192 7634.0 9074.0 9259.0 9379.8 11035.0 11056.2 11085.0 11173.3 13541.0 13952.9 14485.9 13533.8 14545.0 15873.0 15898.0 16245.0 16260.0
GMDSS
International DSC frequencies
GMDSS-DSC 100 2187.5 4207.5 6312.0 8414.5 12577.0 16804.5
GMDSS-DSC 1200 156,525 (Ch.70)
POCSAG (VHF)
POCSAG 1200 DFSK France and Germany: many channels from 465,970 to 466,250, spacing: 12.5 khz. UK: around 140 and 155 Mhz.
POL-ARQ
POL-ARQ 100 4016.8 4961.8 6769.0 6937.0 7484.0 7621.8 10313.8 10389.0 11470.8 13466.8 13851.9 13916.8 14903.1 15651.8 15791.9 18063.8
RUM-FEC
RUM-FEC 164.5 3851.0 5246.3 5234.0 5252.0 5767.0 6853.0 6857.0 8024.9 8027.0 8028.0 10493.0 10486.6 10493.0 12204.8 13338.8 13445.9 13502.0 13497.8 13549.0 13878.0 14681.0 16053.0 16059.0 16.345.1 16347.8 17451.8 17456.0 17469.0 17483.3 18551.5
RUM-FEC 218.3 5248.1 6850.0 8012.5 8024.2 8029.0 10432.0 10483.0 11416.5 11426.5 11457.0 11463.0 14520.7 16054.0 16318.0 16321.0 16325.0 16327.0 16344.3 16352.2
SI-ARQ
SI-ARQ5 96 7892.5 18411.4
SITOR-A and B
SITOR-A and B 100 Very numerous frequencies in marine bands, channel spacing: 0.5 Khz: 4210.5 - 4219.0 6314.5 - 6330.5 8416.5 - 8435.0 12579.5 - 12656.5 16807.0 - 16902.5 19681.0 - 19703.0 22376.5 - 22443.5 26101.0 - 26120.5
SITOR-B 100 (NAVTEX) 0518.0 (International, English) 0490.0 (National, vernacular)
SWED-ARQ
SWED-ARQ 100 14970.0 15821.7 15822.5 15861.7 16106.9 18186.8
1382
1382 1200 In France, output frequencies in the band 86.100-86.200. Channel spacing: 12.5 Khz. Input frequencies 3 Mhz below (83.100-83.200).
For more informations about utility radio stations (list of frequencies, transmission
modes...), please refer to the following guides and publishers
| - Guide to utility radio stations - Shortwave frequency guide by Joerg Klingenfuss Klingenfuss
Publications |
- Ferrell's Confidential Frequency list by Geoff Halligey PW Publishing Ltd |
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