[Single Tone],
[Synchronous Data],
[Asynchronous Data],
[Multi-tone],
[Slow Scan TV],
[Facsimile],
[Synchronous Bitstream],
[Asynchronous Bitstream],
[Voice Frequency Telegraphy],
[Phase Shift Keying],
[Mystery]
CW Morse code still used by the Amateur community and
Marine operations. Speed varies depending on whether
hand generated or machine generated.
ARQ6-70 A simplex ARQ system with a 70 bit block length using
the ITA3 alphabet. A regular user is unknown but the
French Diplo service has in the past. No loggings have
been found for quite some time and no loggings have
been reported in the previous year via WUN.
ARQ6-90/98 6-character-block simplex ARQ used by French and
Italian Diplo services, typically 200 bd. ARQ-6/90
and ARQ-6/98 differ in their inter datablock timing.
G-TOR Golay Transmission over Radio. An amateur system
developed by the engineers at Kantronics, Inc. G-tor's
"claimed" main advantage is speed - up to 4x faster
than pactor. It also incorporates a data-interleaving
system that assists in minimizing the effects of
atmospheric noise and has the ability to fix garbled
data. G-tor tries to perform all transmissions at 300
bd but drops to 200 bd if difficulties are encountered
and finally to 100 bd. All acknowledgments (ACK's and
NAK's) are sent at 100 bd.
SWED-ARQ Swedish Adaptive simplex ARQ used by Swedish Diplo
services, typically 100 bd. Comes in the 3 packet
lengths: 3, 9 and 22. Universal literature refers to
this as short, medium and long. The system is able to
change packet length in mid transmission, depending on
conditions, giving SWED-ARQ its adaptive capability.
Also known as ARQ-SWE.
TWINPLEX 4 frequency diplex system used by organizations such
as Interpol and United Nations and the government Diplo
services of countries such as Australia, Denmark,
Holland, Norway, Pakistan and Spain. Typically runs at
100 and rarely at 200 or 300 bd. This 2 channel system
supports several different shift parameters and word,
bit, character or not-interleaved of the channel
characters but is easy to identify because of its 4 peak
signal. Reference Table 4-E for all the parameters. This
system was developed by Thrane and Thrane of Denmark.
Also known as F7B4.
SITOR-A The most common ARQ signal used by Amateur, Marine
and some Gov. Diplo services, typically 100 bd. Also
known as ARQ or TOR.
SI-ARQ Siemens Simplex ARQ used by Austrian and Indonesian
Diplo services, typically 96, 144, 192 or 200 bd.
Also known as ARQ-S or ARQ-1000S.
MERLIN/ALIS/ Rohde & Schwarz simplex ARQ used by German, Italian,
RS-ARQ and other Diplo services, typically 228.7bd and 240bd
but reports of 457.0 have been noted. There appears to
be no "real" name for the data system. Now referred
to in Klingenfuss documents as ALIS but strictly
speaking, ALIS is only the automatic link processor
and frequency management system. It is not responsible
for generatic the traffic. ALIS is therefore somewhat
of a misnomer. The actual modems generating the traffic
are the GM857 and GM2000. Our suggestion is to stick
with RS-ARQ as the system name.
Many of the diplo users actually control their networks
with MERLIN, the name for the R&S complete data-over-
radio and message handling system that can transparently
deal with many types of data. Consequently it has many
modes. See Klingenfuss Radio-teletype Code Manual 13th
Ed. under "ALIS" for more information. Formerly
referenced as RS-ARQ in the 12th Ed.
DUP-ARQ A semi-duplex ARQ system used by the Hungarian Diplo-
matic service and at least one Far Eastern Diplomatic
service but this system is not unique to the Hungarians.
Baud rate is typically 125 bd. If a DUP-ARQ system
detects interference it will change frequency in 400Hz
steps. If a 3kHz channel is full of interference the
system will select another frequency. Also known as
ARTRAC, or 125-ARTRAC.
DUP-ARQ-2 An ARQ system with the same block timing as DUP-ARQ
but runs at twice the baud rate - 250 bd. Also known
as ARTRAC II. First listed in Klingenfuss 14th Ed.
Utility Guide. This system has be monitored sending
foxes de stc.
IRA-ARQ Duplex ARQ with IRA (ITA-5), used by Czech/Slovak
Diplo stations, typically 171.42, 200.2, or 300.3 bd.
A tip for monitors is to remain on frequency with the
decoder set to ASCII/ITA-5 at the same speed that the
ARQ is sending. Once the transfer is complete, operator
chat often takes place in standard ASCII or BAUDOT.
PACTOR A system designed with a combination of packet and
sitor techniques used by amateurs, MARS stations and
many quasi-governmental organizations. Mutually incom-
patible variations are becoming common with changes
made to the packet structure to support privacy re-
quirements of the various quasi-governmental users.
Commonly referred to as UN-pactor or ICRC-pactor. The
developers of Pactor, Special Communication Systems
(SCS), have actively pursued commercial acceptance of
this protocal and as many as 5 different variants have
been noted. Code 30 defines the following variations:
Common User Label
-------------- --------
Pactor 1 Amateur PACTOR
Pactor 2 ICRC PACTOR-I
Pactor 3 UNHCR PACTOR-U
Pactor 4 IFRB
Pactor 5 is found on the Wavecom 41pc unit but the
user of the variant is unknown.
ICRC - International Committee of the Red Cross
UNHCR- UN High Commissioner for Refugees
IFRB - International Frequency Management Board
Pactor I is the origional implementation and is also
known as FSK Pactor. Pactor II is DSP based and is as
much as 8 times faster then Pactor I.
A Pactor Level II signal features 2 tones w/200Hz shift
using baud rates of 100 or 200 fitting into a 500Hz
channel. Pactor II is a half-duplex synchronous ARQ
system and designed to be backward compatible with the
older Pactor Level I protocol. The system can handle
raw 8 bit data and ASCII compression. Depending on band
conditions the data throughput can be increased by
changing the modulation form used. Maximum throughput
is 800 bps. Pactor Level II is operational in Europe
and is in the manufacturing stage in the US.
format baud rate
------- ---------
DBPSK Differential Binary PSK 200 bps
DQPSK Differential Quad PSK 400 bps
8-DPSK 8-phase Differential PSK 600 bps
16-DPSK 16-phase Differential PSK 800 bps
While packet signals are a non-continuous signal much like SITOR-A their sound is totally different from the regular chirp, chirp sound of SITOR-A. These signals do not have the regular cadence of SITOR-A but have more of a long duration burst sound.1-C. PACKET-like signals or ASYNCHRONOUS DATA BOCK signals.
HC-ARQ Haegelin-Cryptos simplex ARQ used by UN and Red Cross
services. This synchronous system uses a packet like
protocol with no defined timing and supports packet/
block sizes of 38, 68 and 188 ITA2 characters but
always runs at 240 bd.
PACKET A mode used by radio amateurs, and to a lesser degree,
UN forces, to allow data communications between PCs
and dumb terminals. On HF there are 2 main protocols
in use;
AX.25 Typically 300 bd on SW. Data is arranged in packets of
up to 256 bytes of 8 bit ASCII data. Each packet con-
tains a 1 byte start flag, 3 byte address field, 1 byte
control field, 0-256 bytes of data, 2 byte CRC and
finally a 1 byte end flag. Packets are transmitted with
no fixed timing. See the latest specification published
by the American Radio Relay League (ARRL) for complete
details on this system. There is also some 1200 baud
PSK work done in the 10 meter ham band.
Automatic Packet Reporting System or APRS, is an appli-
cation that runs "on top of" AX.25. It was invented by
Bob Bruninga WA4APR that utilizes GPS data to plot a
packet station's location on a map of a given region,
city, state, or even country. Due to the graphics
involved, units like the M8000 will not read this data;
however, units like the PK232 can read it with the use
of special software. Signals utilizing this mode are
found in the 40 and 30 meter bands (for example)
utilizing 'gateways' into 2 meters.
CLOVER A system originally developed by Ray Petit, W7GMH, and
now marketed by HAL Communications. The original modem
was named CLOVER-I, the latest DSP based modem is
named CLOVER-II. It sounds like a "canary" when trans-
mitting. A signal consists of a 1s burst + a long 20s
data transmission. Clovers key characteristics are band-
width efficiency with high error-corrected data rates.
Clover adapts to conditions by constantly monitoring
the received signal. Parameters which can affect quality
and reliability of the transmission such as block data
errors, phase dispersion, frequency offset, and signal
to noise ratio are monitored. Based on this monitoring,
Clover determines the best modulation scheme to use.
Clover supports the following formats:
format baud rate
------ ---------
BPSM 4 pulse binary phase 125 bps
QPSM 4 pulse quad phase 250 bps
8PSM 4 pulse 8 phase 375 bps
16PSM 4 pulse 16 phase 500 bps
8P2A 4 pulse 8 phase 2 amplitude 500 bps
16P4A 4 pulse 16 phase 4 amplitude 750 bps
Total band width for all modes is a narrow 500 Hz with
a symbol rate of 31.25. Also known as 500Hz-CLOVER.
400Hz-CLOVER This is regular DSP based CLOVER packed into a narrow
400 Hz bandwidth. This form of CLOVER is proprietary to
GLOBE WIRELESS and was developed in cooperation with
HAL Communications for use in Maritime communications.
Also known as CLOVER-II or KFS-CLOVER. This form of
CLOVER cannot be demodulated with standard CLOVER boards
as the DSP programming, power requirements and memory
capacity of the board was redone to support the new
narrow bandwidth.
CLOVER-2000 A commercial form of CLOVER developed by HAL Communi-
cations, now in beta test. Supports 4x the speed of
standard CLOVER and uses a bandwidth of 2kHz. With the
doubling of tones HAL has effectively doubled the rate.
Symbol rate is now 62.50. The 8 tones that make up this
signal are spaced 250Hz. Maximum bit rate is 3000bps.
BPSM, QPSM, 8PSM, 8P2A, and 16P4A with "auto-throttling"
are supported. Data packets are long, about 4s in dur-
ation. Idle chirps are short, about .3s in duration with
about .8s between chirps. Also known as "8-tone CLOVER",
Q-CLOVER, or QUAD-CLOVER.
format rate
------ ---------
BPSM 4 pulse binary phase 500 bps
QPSM 4 pulse quad phase 1000 bps
8PSM 4 pulse 8 phase 1500 bps
8P2A 4 pulse 8 phase 2 amplitude 2000 bps
16P4A 4 pulse 16 phase 2 amplitude 3000 bps
HF=Datalink An ACARS-like system used between airplanes and ground
stations for passing tech info is now operational on HF.
Ground stations broadcast system management uplink
packets ('squitters') every 32s on 3 or more active
frequencies. This assists in finding error free channels.
Adaptive rates of 150, 300, 600, 1200 and 1800 bps are
supported. See Monitoring Times 6/95 Plane Talk or the
Digital Review column in WUN 10/95 (V1/10) and WUN 11/95
(V1/11) for more info. Also known as HFDL or ACARS on HF.
PICCOLO Originally developed in 1957 in Great Britain at the
Diplomatic Wireless Service or as it is known today the
Communication Engineering Department of the British
Foreign and Commonwealth Office (FCO). The original
system was a 32 tone system and the development team
was lead by J.D.Ralphs. This multi-tone synchronous
system is used mainly by the British Gov., Australian
Gov. stations and some South American Mil. (Peruvian?).
A 6 tone system (MK6) using ITA2 operates at 75 baud.
A 12 tone system (also MK6) using ASCII/ITA5 also exists
but the 6 tone system is the more common. Both systems
can still be found on the air and the modern MK6 unit
is manufactured by RACAL. Reference the Klingenfuss
RadioTeletype Code Manual 13th Edition for the tone
pairs and PICCOLO alphabet.
COQUELET COQUELET Mk I is an asynchronus 13 tone ITA2 system
used by French (possibly abandoned) and Belgian mil./
police. COQUELET Mk II is a synchronous 8 tone ITA2
system used by Algerian Diplo and Customs. COQUELET
Mk I is also referred to as COQ13. COQUELET Mk II is
also referred to as COQ8. Also note that users of COQ8
seem to be using a hybrid COQ8/COQ13 system (possible
COQUELET Mk III?) with fourth shift Arabic/Latin
alphabet.
COQ13 translates each 5 unit ITA-2 character into a
sequence of 2 tones out of total of 12. A 13th tone
represents the idle condition. The system takes each
character and breaks it into a 3 bit piece and a 4 bit
piece. The first 3 bits of the character are sent as 1
out of 8 possible tones (1-8) and the second 4 bits are
sent as 1 out of 4 possible tones (10-13). The idle
tone, tone 9, is usually 1052 Hz up from the suppressed
carrier point of the station's SSB transmitter and is
heard only during the idle or standby condition. Each
tone is 75 ms in length or one character is 150 ms long
giving the system a baud rate of 13.5.
COQ8 directly translates each character into a set of
2 tones from a total set of 8 tones. The idle condition
used by this system is made up of tones 1 and 8 sent
alternating. Each tone has a duration of 37.5 ms, with
1 tone taking 75 ms, giving an effective baud rate of
26.67.
Reference Klingenfuss RadioTeletype Code Manual 13th
Edition for this systems tone mapping and alphabet.
CROWD36 A Soviet MFSK system using 36 tones based on British
Piccolo MK1. CIS Diplo service is the main user.
Typically found at 40 baud. A spectrum analyzer will
show the tones arranged in 3 distinct group of 10+11+11
tones. Tones are spaced 40Hz apart and tones 1, 12, 24
and 36 are rarely used so you are likely to see an 80Hz
gap between groups. Each of the 32 tones represents
one ITA2 character code. Also known as CIS Piccolo,
CIS 10-11-11 MFSK or URS multitone.
MIL188 An 8 tone MFSK system running at 125 bps. Tones are
spaced 125Hz or 250Hz. Also known as NATO MIL188 or
MFSK188.
NOTE: the only known sample of this system is actually
believed to be tt2300b so how this signal really looks
and sounds is unknown.
TT2300b/TPLEX An 8 tone, 100bd adaptive, synchronous system manu-
factured by Thrane & Thrane of Denmark. Primarily
designed to be connected directly to the serial port of
a computer, the system features auto-dial, subscriber
addressing, electronic mail and can also be connected
to a Fax machine. The full-duplex, error-correcting
(24 unit CRC) link protocol is completely transparent
to any type of data coding. Believed to be used by
French Diplo and the UK Civil Aviation Authority. This
may be logged in some commercial frequency lists as
TT2300-ARQ. The manufacturer's name for the protocol/
coding is TPLEX.
Probably frequencies: 5028.7, 5109.7, 7716.7, 7719.7kHz
8 tones, 200Hz spacing, ACF=8
MERLIN/ALIS-2/ This is the 240 bd 7 tone burst ARQ mode used in the
RS-ARQ Rohde & Schwarz MERLIN modem. The label ALIS-2 first
appeared in the Klingenfuss 14th Ed. Utility Guide.
Reference the MERLIN/ALIS note above on naming.
LINK 11 A US Military/NATO 40 DPSK synchronous system using 15
tones (1 doppler tone + 14 data + 1 sync tone), the
14 data tones are 4-PSK modulated and spaced every 110
hz. The sync tone is 2-PSK modulated. Typical rates of
1364 b/s or 2250 b/s. This is a ground wave only system.
Klingenfuss indicates a baud rate 2400. See also
MIL-STD-188-203-1A. Also known as TADIL-A or "alli-
gator". Largest manufacturer of LINK 11 equipment
is Rockwell-Collins.
MS-5 This is the Russian 12 tone vocoder system. MS-5 has
a maximum capacity of 4800 bits/s and occupies a band-
with of 300 to 3400 Hz. The system operates in 2 modes:
1) FT mode, an FSK mode with a shift of +/- 60Hz.
2) 2AT mode, a 2 tone keying mode with a freq. shift
of 1440Hz or 480Hz.
FT mode has 6 sub-channels with mark/space freqs of:
ch 1: 540/660 ch 2: 1020/1140 ch 3: 1500/1620
ch 4: 1980/2100 ch 5: 2460/2580 ch 6: 2940/3060
each with a freq shift of 120Hz. Data is transmitted
over the 6 sub-channels at a rate of 200bd or over 1
channel at a rate of 1200bd.
2 different 2AT modes (2AT is double amplitude tele-
graphy) are supported. The first 2AT mode has 3 sub-
channels with mark/space freqs of:
ch 1: 600/2040 ch 2: 1080/2520 ch 3: 1560/3000
each with a freq shift of 1440Hz. The second 2AT mode
also has 3 sub-channels with mark/space freqs of:
ch 1: 600/1080 ch 2: 1560/2040 ch 3: 2520/3000
each with a freq shift of 480Hz. Using 2AT mode data
is transmitted over the 3 sub-channels at a rate of
200bd or one channel at 600bd.
This system has a distinctive pilot tone at 3300Hz
above a kHz point. Reference ITU Reports of the CCIR,
1990, Annex to Volume III, Fixed Service at Frequencies
below about 30MHz - Report 703-2 "Use of Channels with
Bandwidth 300-3400Hz in SSB and ISB Systems".
ANNEX 10 An ARINC HF SELCAL system.
HELLSCHREIBER FAX-like mode used by Chinese Internal Press (still?)
now used infrequently by European amateurs on 80m and
40m.
FAX A picture transmission mode used by weather (meteo),
some Press and less often, amateurs. Pictures are sent
line by line and to correctly receive a picture you
must, at most, have the drum speeds (RPM) in sync. Usual
RPM values are 60, 90, 120, 240. Less important is the
IOC (Incidence of Cooperation). Usual values for IOC
are 288, 352, 576. For the picture to be received as
it was sent both RPM and IOC should match the senders
RPM and IOC. It is true that FAX use is in decline and
will continue to do so in the near future.
A recent wrinkle now appearing in the declining FAX
signal arena is the introduction of 'encrypted' FAX
transmissions. The start, stop, and phasing signals
appear normal but the picture data seems to use some
sort of modified code. Current speculation indicates
Huffman encoding or a Modified Read Code with lines
only including the pixels changed from the previous
line.
Reference Klingenfuss Guide to Facsimile Stations for
a discussion of FAX theory and examples.
A picture transmission mode developed and used by the Amateur community.
While these signals are FAX-like in function they do not possess the
scratching quality of the FAX signal. The sound of an SSTV signal is more
tonal in its composition. I do not believe that each mode can be
distinguished by ear.
Currently the most popular mode found on the airwaves in North America is
Scottie S1, followed less frequently by Scottie S2, Robot 36 and 72 and
finally some Martin M1. Europe seems to be mostly Martin M1.
SSTV modes
------------
SC-1 and SC-2 were developed by Volker Wraase in Kiel, Germany.
Martin was developed by Martin H. Emmerson, G3OQD/England.
Scottie was developed by E.T.J. Murpy, GM3SBC/Scotland.
Robot was developed by Robot Research.
+------------------------------------------- Mode
| +------------------------------- Scan Lines
| | +------------------------ Color/RBG seq. or B/W
| | | +----------------- Time (sec)
v v v v Comments
+----------------+-----+-------+-----+-------------------------------------
|AVT 24 | 120 | Color | 24 | There is a 5s digital header and
|AVT 90 | 240 | Color | 90 | there is no horizontal sync
|AVT 94 | 200 | Color | 94 |
|AVT 188 | 400 | Color | 188 |
|AVT 125 | 400 | B/W | 125 |
+----------------+-----+-------+-----+-------------------------------------
|Wraase SC-1 24 | 120 | Color | 24 | -top 8 lines are grey scale
|Wraase SC-1 48 | 240 | Color | 48 | -top 16 lines are grey scale
|Wraase SC-1 96 | 240 | Color | 96 | -top 16 lines are grey scale
|Wraase SC-2 30 | 128 | R-B-G | 30 |
|Wraase SC-2 60 | 256 | R-B-G | 60 |
|Wraase SC-2 120 | 256 | R-B-G | 120 |
|Wraase SC-2 180 | 256 | R-B-G | 180 |
+----------------+-----+-------+-----+-------------------------------------
|Scottie S1 | 240 | G-B-R | 110 | -top 16 lines are grey scale
|Scottie S2 | 240 | G-B-R | 71 | -top 16 lines are grey scale
|Scottie S3 | 120 | G-B-R | 55 | -top 8 lines are grey scale
|Scottie S4 | 120 | G-B-R | 36 | -top 8 lines are grey scale
|Scottie DX | 240 | G-B-R | 269 | -top 16 lines are grey scale
+----------------+-----+-------+-----+-------------------------------------
|ScanMate1 | 320 | Color | 391 |
|ScanMate2 | 320 | Color | 261 |
+----------------+-----+-------+-----+-------------------------------------
|Martin M1 | 240 | G-B-R | 114 | -top 16 lines are grey scale
|Martin M2 | 240 | G-B-R | 58 | -top 16 lines are grey scale
|Martin M3 | 120 | G-B-R | 57 | -top 8 lines are grey scale
|Martin M4 | 120 | G-B-R | 29 | -top 8 lines are grey scale
+----------------+-----+-------+-----+-------------------------------------
|Robot 12 | 120 | Y-C | 12 | Color is sent as Luminance and
|Robot 24 | 120 | Y-C | 24 | Chrominance
|Robot 36 | 240 | Y-C | 36 |
|Robot 72 | 240 | Y-C | 72 |
|Robot 8 | 120 | B/W | 8 | Not a true B/W mode. Green element
|Robot 12 | 120 | B/W | 12 | sent as B/W image
|Robot 24 | 240 | B/W | 24 |
|Robot 36 | 240 | B/W | 36 |
+----------------+-----+-------+-----+------------------------------------
SSTV VIS code
-------------
With the introduction of Robot 1200C, Robot Research introduced the VIS
code, which is used to indicate the speed and mode at the beginning of the
transmission. The VIS code, when decoded by the receiving station, will
let the receiver automatically set the necessary parameters for proper
reception. The VIS code is sent as part of the vertical sync pulse and
is 10 bits long lasting 10*30ms. The start and stop bits are represented as
a 1200Hz tone with the remaining 8 bits (including 1 even parity bit) left
for encoding information. This breaks down as 1 30ms start bit at 1200Hz,
7 data bits, each 30ms, sent Lowest Significant Byte (LSB) first (logical
'1' is transmitted as 1100Hz, logical '0' is transmitted as 1300Hz). 1 30ms
even parity bit and 1 30ms stop bit as 1200Hz. The table is fairly extensive
so for now reference the following www page(s):
SSTV Info (valid as of 1/19/96)
SSTV Modes (valid as of 1/19/96)
36-50 A Russian Navy synchronous bit stream system whose
real name is unknown at this time. Known system para-
meters are as follows: the system is commonly found in
Europe but can be heard in the US, traffic runs at 50
bd with no apparent ACF (ACF=0) and then idles with 36
bd (ACF=2). As the traffic switches from 36bd to 50bd a
preamble can be detected running with ACF=70. The
system appears to be synchronous with 1 stop bit and a
shift of 250Hz and sometimes 500Hz. In between, or at
the end of messages, FSK CW has been heard using the
callsign RDL.
81-81 Russian/URS Military System mainly 81 bd, pseudo random,
one or two characters, 12 bits, usually encrypted -
operator chatter can sometimes be found in the clear
using Baudot w/Cyrillic M2 alphabet. It is mainly a 2
ch system but there is a 40.5 bd signal that is a 1 ch
variant. Most commonly found baud rates are 36.5, 40.5
for the 1 ch version and 73 and 81 for the 2 ch version.
ARS-GUARD A Saudi National Guard synchronous FEC system, running
at 125 bd and 170Hz shift (ACF=48 or 96). Check out the
following frequencies:7672.5, 7869.5, 12257.5, 12357.5,
12362.6, or 12457.5.
ARQ-E A very common single channel duplex ARQ system, made by
Siemens, used by French Military Forces and the German
Gov., typically 48, 64, 72, 86, 96, 144 or 192 bd. Also
known as ARQ-1000D.
ARQ-E3 Another very common single channel duplex ARQ system
used by French Military Forces, typically 48, 64, 72,
86, 96, 144 or 192 bd.
ARQ-M2 A commonly found full duplex, synchronous, time division
multiplex ARQ system w/2 data channels, typically using
87, 96 or 200 bd. French Military Forces are the most
commonly found user and this system can idle for long
periods of time with no traffic. This system comes in
2 flavors: one is defined by the old CCIR 242 Recom-
mendation and the other is defined by the newer CCIR
342 Recommendation. Both forms can still be found. Also
known as TDM, ARQ-28, TDM-2, TDM-242, TDM-342 or 96-TDM.
See Section 4 for Recommendation differences.
ARQ-M4 A rarely found full duplex, synchronous, time division
multiplex ARQ w/4 data channels, typically using 87,
96, 192 or 200 bd. This system had been used by Chinese,
Vietnamese and Spanish embassies. Loggings within the
past year indicate use by some French Military Forces
stations. This system can also idle for long periods of
time with no traffic. This system also comes in 2
flavors as defined by the same recommendations as
ARQ-M2. Also known as ARQ-56, TDM-4, TDM-242, TDM-342
or 192-TDM. See Section 4 for Recommendation differences
ARQ-N A single channel duplex ARQ system used by Italian
Diplo services, typically using 72, 96, 144 or 192 bd.
This system is related to ARQ-E but does not inverse
any bits.
AUTOSPEC A FEC system used by British coastal stations to
communicate with North Sea oil rigs, typically 62.3,
68.5 or 102.7 bd. Also known as Autospec-bauer or
Bauer. No loggings have been recorded in the previous
year.
SPREAD A FEC system, used by Romanian diplo stations, using
the Bauer code used by Autospec, with characters spread
over a large time span, designed to reduce burst and
fading errors. Typically 68.5, 102.7 or 137 bd. Also
known as SPREAD-11, SPREAD-21 or SPREAD-51 depending
on data spread in effect.
CIS A single channel duplex system using 11, 14 or 27 bits.
CIS-11 is used by Russian meteorological stations,
CIS-14 is reported to be used by Russian PTT stations
on links to the former republics. CIS-14 also comes in
a 28bit frame variant that consists of 2 14bit frames
running at 200 bd. Typical baud rates are:
CIS-11 - 50, 100, 150, 200 and 300 bd
CIS-14 - 42.1, 47.5, 48, 50, 70.5, 72, 83.3, 84.21,
94.11, 96, 100, 144, 200 and 288 bd
CIS-27 - 50 and 100 bd.
CIS-11 is also known as TORG-11. CIS-14 is also known
as PARITY14.
FEC-A/FEC-100 A system used by Turkish and German Press and German,
French and Serbian Diplo services, typically 96, 144,
192 or 288 bd. Siemens is the manufacturer and refers
to this system as FEC-100. There have also been reports
of a FEC-101 variant.
GMDSS/DSC Digital Selective Calling is a variation of Sitor-B,
100 baud 170 shift, but uses a special set of 127
symbols with a 10 bit error correcting code. The
system is defined in the ITU recommendation ITU-R
M493-6. A DSC signal is short, about 6-7 seconds on
MF/HF and contains the following: station ID, priority,
station being called, frequency to use. This system is
used to establish the initial contact between ships and
shore stations using GMDSS.
DSC signals can be found the following frequencies:
2187.5, 4207.5, 6312.0, 8414.5, 12577.0, 16804.5 (also
on VHF on Ch. 70 - 156.525 @ 1200bd). See Digital
Review column in WUN newsletter Vol. 1, No.12 December,
1995 for a good writeup on GMDSS/DSC.
HNG-FEC A FEC system used by Hungarian Diplo services, typically
100.05 bd. See Klingenfuss RadioTeletype Code Manual
13th Edition for teleprinter alphabet used by this
system.
IRA-ARQ An ARQ system used by the Bulgarian Diplo services,
typically 75, 100, 110, 150, 180, 200, 240, 300 or
600 bd. A tip for monitors is to remain on frequency
with the decoder set to ASCII/ITA-5 at the same speed
that the ARQ is sending. Once the transfer is complete,
operator chat often takes place in standard ASCII or
BAUDOT.
POL-ARQ A single channel duplex ARQ system used by Polish and
Italian Diplo services, typically at 100 bd. Can be
easily confused with Sitor-B.
ROU-FEC A FEC system used by Rumanian Diplo services, typically
164.48 or 218.3 bd. Signals can be encrypted, in the
clear or bit-masked (have been known to use 10, 15, 24
or 31). Had been referred to as SAU-FEC in the past and
renamed to RUM-FEC by Klingenfuss Publications.
SITOR-B A FEC system used by Marine Information services and
the Amateur Radio community, typically 100 bd but an
odd baud rate of 109.4 has also been monitored. Also
known as FEC or AMTOR.
SI-FEC A Siemens FEC system used by Austrian and Indonesian
Diplo services, typically 96, 192 or 200 bd. Also
known as FEC-S or FEC1000 Simplex.
TORG-10/11 A Soviet 2 frequency duplex FEC system used to transmit
Meteo data, 10/11 bit blocks of ITA2 coded data plus
error correction. Typically 100 bd, 500Hz shift.
NATO-75 Various NATO members have equipment which generates
NATO-100 75bd or (more rarely) 100bd RTTY with a variety of
shifts from 85Hz to 850Hz. Within the service, these
systems are usually known as RATT or CRATT (Crypto RAdio
TeleType). We also have indications of the system being
known as "Beaver" (US) or Link 4, although this is
unconfirmed at present.
Traffic can often be recognised by twice repeated header
block of 256 bits which shows an ACF of 64, and by a
period of sustained reversals between "messages". The
remainder of traffic is pseudo-random.
Such a system can be found permanently on 4711, 6702,
and 11264kHz. We believe that this system is closely
related to the Royal Navy's common "Fleet Broadcast"
75bd or 100bd system which has a message preamble of 16
RYs and VMGTCNJBH in Baudot before switching to
encryption.
BAUDOT A common signal used by the Amateur community, many
military and government services, typically 50, 75 or
100 bd. Inversion is possible but not frequently
encountered on the data bits, giving 2^5 (32) possible
arrangements. Also known as RTTY or ITA2.
ASCII A rarely found signal used by the amateur community
typically 110, or 300 bd but has been tested in recent
times by VOA. Amateur station W1AW still transmits
ASCII bulletins. Also known as ITA5 or IRA.
VFT A general term used to define many kinds of multi-
channel signals used by British Military, Canadian
Military and US Military. Many configurations are
possible. Also known as FDM or WTK.
Some common VFT configurations have been noted;
* 2 channel interleaved VFT using 50/340 baudot and
96/340 2ch ARQ-M2
* 1 75/340 baudot or 1 50/340 baudot and up to
12 170Hz channels with diversity
The following VFT signals are commonly found in use
by the named users so the authors have assigned names
for use as a starting point in future discussions.
* RUS-144: 3 channels of 144bd/200Hz FEC system, with
channels spaced at 950Hz. A synchronous system with
no apparent ACF. Noted on 8077kHz (nightime) and
14814kHz (daytime) and used by Russian PTTs. Has also
been noted in the past on 8063/14327.
* 3 ch FEC-100: 3 channels of FEC-100 (possibly FEC-101
too) are known to be in use by Israeli Mil, German
Diplo and Serbian Diplo. Usual channel speeds are 3
channels of 144, 96 or 192bd with shifts between 80
and 170Hz. The 3ch 192bd/170 with channel spacing of
680Hz is probably German Mil/MOI.
* MOI-VFT: The German MOI and police use a 3 channel VFT
comprising 96bd, 80Hz shift ARQ-E on their inter-city
links. Commonly heard below 5MHz in Europe.
* 3 ch 150 FSK: The German Navy, primarily Wilhelmshaven
(DHJ59) has been noted using a VFT configuration of
3 channels running 150bd/170 FSK with each channel
spaced at about 700Hz. The 150bd FSK system is UNID.
* 3 ch Piccolo: 2 and 3 channel VFT piccolo have been
noted. Channel 1 and 2 are usually found sending
bitstream encrypted traffic and the Engineers Channel
idles or sends plain-text operator chatter. There is
also the possibility of a 4 channel configuration.
The following 3 channel offsets (measured from the
carrier point) are usually found as:
Engineers Channel: +0.51kHz offset
Traffic 1: +0.91kHz offset
Traffic 2: +1.31kHz offset
BR6028 6028 Series Diversity is a commonly found VFT system
using 7 channels of 50 bd or 75 bd baudot each with
170 Hz shift used by US and Canadian Military. Channels
are shifted in time and channels with heavy inter-
ference can be locked out causing the transmitter side
to stop using the interfered with channel. This
accounts for those less then 7 channel VFT's sometimes
found. Also known as "BARRIE" or 6028.
Belgian Diplo (MFA Brussels and Embassy Beirut) have
been noted using what seems to be a modified BR6028
system. Configuration shows:
pilot tone, ch 1, NO ch 2, Ch 3 - 7
Channel 2 never seems to be present. All channels carry
100bd/170 Baudot delayed in time by 0.5 secs. This VFT
form has been noted on the following frequencies:
11107, 14476 and 14904 most mornings (06-08UTC).
MULCAST A system used by the US Military composed of 16
channels each with an 85 Hz shift.
2-4MHz region: Navigational aids sending Differential Global
Positioning System (DGPS) information using 250bps 4-phase
(or Quarternary) PSK (QPSK). Try 2834.0, 2805.0, 3226.0kHz
3-13MHz region: Soviet Mil/PTT system sending 1280bps data using
a 4-phase, Offset QPSK scheme. These stations are recognizable in
that they are all placed on .081 offsets from a kilohertz or half
kilohertz point. At least 20 channels are known to be in almost
constant use. Try 9058.081, 7663.581, 5752.081, and 13369.081kHz
amongst others.
Note: Recently many of these frequencies have been sprouting lower
sideband twins. For example 11422.081 is paired with 11417.93,
9209.081 is paired with 9204.93. Presumeably this means the system
is operational and adding more capacity.
5-20MHz region: Unknown user and system sending 600bps data using
2-phase, or Binary PSK. Try 10662.8kHz. 1200bps and 2400bps signals
of a similiar nature have been found in this region also.
2400-PSK Believed to be a NATO system, now occupying many
channels and particularly active since the deployment
of IFOR in former Yugoslavia. Sample of frequencies:
2535, 3370, 4578, 6410, 8158, 10480, 16164kHz
1800-PSK A number of signals have been noted sending 1800bps
QPSK data. User is unknown but suspect NATO and is
much rarer than the 2400-PSK.
1600-PSK Believed UK/US Mil system. Sample of frequencies:
4757, 5237, 10386kHz.
DUP-FEC/ A new system appearing with the introduction of the
DUP-FEC-2 Wavecom 41pc (DUP-FEC-2) and the new Klingenfuss Radio
Data Code book (DUP-FEC). No new signals found on the
air as of yet. Suspicion is the system runs at 125 or
250bd.
SUI-FEC A new UNID FEC system running at 68.5bd, 85Hz shift
used by the Swiss Army. Traffic has an ACF=0 but an
ACF=10 at start of messages.
1200-FSK A 1200bps FSK system known to be used by the Italian
Military or Diplo service. Always has a distinctive
.7kHz offset. Has been heard on 6811.7, 9126.7, 10485.7
and 13904.7kHz amongst other channels. Italian operator
chatter in USB on the carrier point can often be heard
prior to messages being sent.
4+4 This is an 8 tone MFSK signal with a unique tone
arrangement. It is a Chinese Diplo system with most
traffic origionating from Peking. Its real name and
base modulation mode (FSK/PSK) are unknown although
analysis suggests that each of the 8 channels is 150bd
BPSK. No estimation of baud rate. The tones are grouped
in sets of 4 spaced 300Hz apart with a 450Hz intergroup
gap, 4 tones w/300Hz spacing, 450Hz gap, 4 tones
w/300Hz spacing.
RAC-ARQ Heres a slick little system documented heavily in
the Radioteletype Code Manual 13th Edition from
Klingenfuss with signal samples available on the
Klingenfuss Modulation cassettes on track 38. Also
if you read the Wavecom W4100 glossy from the company
they list RAC-ARQ as an option. The system is supposed
to be used by British Military stations but multiple
reports from various sources indicate that this system
is probably fabricated by Klingenfuss. Wow.
AIRCALL Another system with very little factual information.
This 7 tone MFSK system appears on the Klingenfuss
recordings cassette on track 32. Sources indicate that
this system is also generally unknown so I will list it
here pending confirmation.
ARTOR Adaptive Robust Transmission Over Radio - an adaptive,
error-free mode for HF using QPSK. First mention of
this system found in the 13th Edition of the Code
Manual. Typical baud rates are documented to be 50,
100 or 200; automatically selected, ARQ and FEC modes
are supported. This system has never been logged and
probably has not been commercially released by the
developer, Ascom Radiocom Ltd, Switzerland. Ascom
did advertise the system (as "ARTOR, our new HF-modem")
in the June 1992 issue of Signal and probably exhibited
at CommunicAsia '92 in Singapore and AFCEA '92 in
Washington D.C.
QAM A system reportedly used by the Chinese, unknown usual
bd rates. A sample of this signal is available on the
Klingenfuss CD (CD#2/Trk9) or Cassette (Trk37). This is
also the name for the modulation technique Quad Phase
Shift Keying with Amplitude Modulation (QAM). No known
loggings to date. Real?