DIGI-MODES Information & Data
CONTENTS
Page 1Cover
Page 2Contents
Page 3Introduction
Page 4AmTOR
Page 5Clover
Page 6Hellschreiber Modes
Page 7MFSK Modes
Page 9MT63
Page 10PacTOR
Page 11PSK31
Page 12RTTY
Page 13 Image Modes
Page 14Advanced Digital Modes
Page 15Modes & Frequencies
Page 21Glossary & Software
Introduction
Communication technologies that are specifically designed to improve "live" HF keyboard operation can now be achieved which previously only theory, too complex, or too costly to implement to be practical. Thanks to the generosity of radio amateurs with programming knowledge, and to the Internet, new and powerful communications tools are available to all hams.
The evolution and wide spread use of the Personal Computer that include a digital sound card for Digital Signal Processing and FFT software techniques, is allowing radio amateurs to use these tools to develop new modes of digital communication.
The distinguishing features of live HF digital operation today are the use of lower power, compact or indoor antennas and courteous operating techniques. Crowding on a single band like 20 metres is partly to blame for this issue. Fortunately, the new digital modes are designed to improve performance for a wide range of operating conditions.
The main advantages are:
- High sensitivity (low power required40 Watts into a dipole)
- Very robust communications (useful in poor conditions QRM)
- Narrow transmission bandwidths
- Error correction codes usingFFT techniques used
- Greater immunity to TVI and EMC
- Computers allow automatic operation and logging
- Digital modes help with amateurs with hearing and speech disabilities, and poor hand coordination.
Most of the modes mentioned here have a complete section devoted to them. When reading the mode summaries, please note the baud rates and bandwidths used. This short paper only presents information and data, with plenty of references for further reading and operating. Armed with this data, I hope to encourage radio amateurs to learn, try to outand enjoy these new digital modes!
AmTOR
SiTOR-B (Sea Teletype Over Radio) revamped to AmTOR (Amateur Teletype Over Radio), being the first amateur modeusing Error Correction Codes. In the early 1990’s this revolutionised Radio TeleTYpe (RTTY).
AmTOR Summary:
Symbol Rate100 baud
Typing speed6.6 CPS (66 WPM)
ITU-R description400HF 1B
Bandwidth400Hz
Modulation2-FSK (Frequency Shift Keying)
Average Power50% (ARQ) Amplitude Request Repeat
100% (FEC) Forward Error Correction
Protocol (Mode A)Synchronous Connected ARQ CCIR 476-4
Protocol (Mode B)Synchronous Unconnected ARQ CCIR 476-4
Character Set Moore 4:3
There are commercial selective-calling versions of Mode B, known as SelFEC and NavTEX marine broadcasts on MF are readily copied with AmTOR. More modern ARQ modes like Pactor are now replacing AmTOR.
Clover
Clover is a PSK mode which provides a full duplex simulation. It is well suited for HF operation (especially under good conditions). The original modem was named CLOVER-I, the latest DSP based modem is named CLOVER-II.
Clovers key characteristics are band-width efficiency with high error-corrected data rates. Clover adapts to conditions by constantly monitoring the received signal. Based on this monitoring, Clover is an advanced communications mode, or rather, a family of modes, designed in the early 1990’s.
Clover Summary:
Symbol Rate31.25 baud
Typing speedapprox 3-50 CPS (30-500 WPM)
ITU-R description500HJ2DEN or 500HJBEN
Bandwidth500Hz
Modulation8, 4, 2-FSK (Frequency Shift Keying) or
2-ASK (Amplitude Shift Keying)
Average Power50%
ProtocolSynchronous Connected ARQ with FEC coding
Protocol Synchronous Unconnected FEC coding
Character Set ITA-5 ASCII (any 8-bit code)
ModeDescriptionData-Rate (bps)Protocol
16P4A16-PSK, 4-ASK750ARQ, FEC
8P2A 8-PSK, 2-ASK500ARQ, FEC
8PSM 8-PSK375ARQ, FEC
QPSM 4-PSK250ARQ, FEC
BPSM 2-PSK125ARQ, FEC
2DPSM 2-PSK diversity62.5FEC
Hellschreiber Modes
This was developed in 1927, by Dr Robert Hell as Hellschrieber (‘Bright-Writer’). Reuters and other press agencies continued to use it throughout World War 11 until the 1960’s, when it was replaced by the Telex Service. China, Japan, Russia, Greeceand Arabic speaking peoples with ideographic languages used variants of Hellschreiber until the mid1990’s when they were finally replaced by FAX. It was first used for Amateur use in 1979.Today Feld-Hell is the most widely used mode.
Feld-Hell Summary:
Symbol Rate122.5 baud
Typing speed2.5 CPS (25 WPM) using original font
ITU-R description350HA1C or 350HJ2C
Bandwidth350Hz
Modulation2-ASK (ON-OFF Keying, CW)
Average Power22%
Protocol Quasi-Synchronous unconnected scanned image
Character Set User selectable fonts
Multi-Tone-Hell Summary:
Symbol Rate0 - 20 baud
Typing speed2 - 3 CPS (20 - 30 WPM) font dependent
ITU-R description200HF1C
Bandwidth100 - 200Hz
ModulationMFSK (7, 9, 10, 12-FSK)
Average Power80% (concurrent) 50% (sequential
Protocol Non-Synchronous unconnected scanned image
Character Set User selectable fonts
PSK-Hell or FM-Hell Summary:
Symbol Rate105 or 245 baud
Typing speed2.5 CPS (25 WPM) font dependent
ITU-R description210H/490HJ2C or 210H/490HF2C
Bandwidth210 or 490Hz
Modulation2-PSK (DPSK)
Average Power80%
Protocol Non-Synchronous unconnected scanned image
Character Set User selectable fonts
MFSK Modes
The first MFSK modes were used by governments and diplomatic services. Namely Piccolo 1957 developed by the British Foreign Office. Coquelet used by French, Belgian and Algerian military and diplomatic services. They were generally equipped with encryption units. The modern MFSK16 mode was developed in 1999, for MS Windows and sound card, using FFT techniques by Nino Porcino IZ8BLY, along with MFSK8, Throb and FSK441. These modes do not require special synchronous modulation, due to the built-in software FFT detectors.
MFSK16 Summary:
Symbol Rate15.625 baud
Typing speed4 CPS (40 WPM)
ITU-R description316HF1B
Bandwidth316Hz
Modulation16-FSK (coherent phase)
Average Power100%
Protocol Synchronous unconnected bit stream with FEC
Character Set Extended 8-bit X-ASCII translated to Varicode
MFSK8 Summary:
Symbol Rate7.8125 baud
Typing speed2 CPS (19 WPM)
ITU-R description316HF1B
Bandwidth316 Hz
Modulation32-MFSK (coherent phase)
Average Power100%
Protocol Synchronous unconnected bit stream with FEC
Character Set Extended 8-bit X-ASCII translated to Varicode
Throb Summary:
Symbol Rate1, 2 or 4 baud
Typing speed1, 2 or 4 CPS (10 - 40 WPM)
ITU-R description100HF1B or 200HF1B
Bandwidth100 or 200Hz
Modulation9-FSK (sequential and 2-tone concurrent)
Average Power80%
Protocol Synchronous unconnected characters
Character Set Restricted, similar to ITA-2
MFSK Modes cont.
Software for FSK441 is called WSJT available from Joe K1JT. Because of the speed at which it operates, it is not practical to decode the received signal in real time. A digital recording is made (wave-file), which is then decoded and displayed.
This wide MFSK mode was designed for signal paths that may be only brief i.e. meteorite-scatter ‘pings’. FSK441 has been met with considerable success on 6m, and has been tried for moon-bounce as well.
FSK441 Summary:
Symbol Rate441 baud
Typing speed147 CPS (1470 WPM)
ITU-R descriptionK21F1B
Bandwidth2205 Hz
Modulation4-FSK (sequential, three symbols/characters)
Average Power100%
Protocol Synchronous unconnected characters
Character Set Restricted, PUA-43 (similar to ITA-2)
MT63
MT63 is a remarkable mode because of its wide bandwidth and usefulness in working in difficult conditions. It was ported from Linux to Windows with a graphical interface, by Nino Porcino IZ8BLY in 1999. Software tuning display for MT63 provides a script page and a waterfall diagram. The favourite frequency is with 14.110MHz using USB, 100 Watt transceivers are best to operate using 25 Watts because of the linearity requirements. Tuning on receive is done by monitoring the waterfall diagram. Decoding of the phase information is provided by a 64-bin FFT across the signal. The Walsh function provides a very clever error correction coding, FEC. Because of the large amount of processing required, operators leave good-sized gaps between overs.
MT63-1K Summary:
Symbol Rate10 baud
Typing speed10 CPS (100 WPM)
ITU-R description1K00J2DEN
Bandwidth1000 Hz
Modulation64-PSK
Average Power80%
Protocol Synchronous unconnected FECWalsh coding
Character Set ASCII (7-bit)
PacTOR
PacTOR became extremely popular in the early 1990’s, both for QSO’s and bulletin-boards use. It was developed to replace AmTOR. There is a new version called PacTOR II, which offers even better performance.
PacTOR uses two modes ARQ and FEC.
PacTOR Summary:
Symbol Rate100 or 200 baud
Typing speed6.6 CPS (66 WPM)
ITU-R description400HF1B, 600HF1B
Bandwidth400 or 600 Hz
Modulation2-PSK
Average Power80% (ARQ), 100% (FEC)
Protocol Synchronous connected ARQ
Synchronous unconnected FEC
Character Set ITA-5 ASCII (8-bit)
PacTOR II Summary:
Symbol Rate100 or 200 baud
Typing speedup to 30 CPS (300 WPM)
ITU-R description500HG1B(D), 500HJ2B(D)
Bandwidth500 Hz
Modulation2-DQPSK
Average Power80% (ARQ), 100% (FEC)
Protocol Synchronous connected ARQ
Synchronous unconnected FEC
Character Set ITA-5 ASCII (8-bit)
PSK31
PSK31 was developed in the mid 1990’s, as a replacement for RTTY by Peter Martinez G3PLX to bring it into the 21st century. Later he added a QPSK mode with better error correction code techniques. As a result, PSK31 as we have it today is available with lower power and narrower bandwidth than RTTY. The use of PSK31 now far outstrips use of all other digital modes.
Other versions of PSK31 modes: PSK63F, PSK127F, PSK250F and FSK31 are now in use. Many programs provide a clock phase meter display for tuning purposes, including a waterfall diagram.
PSK31 Summary:
Symbol Rate31.25baud
Typing speed3.5 CPS (35 WPM)
ITU-R description63HF1B
Bandwidth62.5 Hz
ModulationDifferential 2-PSK (BPSK)
Average Power80%
Protocol Asynchronous unconnected chat mode
Character Set Varicode, ASCII
RTTY
RTTY is one of the oldest digital modes, predating all but Morse and Hellschreiber, and has been used by Radio Amateurs just after World War II. In the 1950’s was in conjunction with a Creed Model 7 mechanical teleprinter. In the 1980’s special software was developed for the BBC micro-computer.
A modern RTTYis now available. The much used MMTTY is used world-wide. The pictorial displays makes for very easy tuning.
RTTY Summary:
Symbol Rate45.45or 50 baud
Typing speed6.0 or 6.6 CPS (60 or 66 WPM)
ITU-R description270HF1B
Bandwidth270 Hz
Modulation2-PSK
Average Power100%
Protocol Asynchronous chat mode
Character Set ITU-R ITA2
Image Modes
Slow Scan Television (SSTV) has been developed by Radio Hams in the 1950’s using Cathode-Ray-Tubes with very long persistence phosphors. It used line scanning being generated in a similar manner to that of fast TV. Around 1995 simple SSTV for the mass Amateur market arrived with DOS and Hamcomm interface software EZSSTV in 1990 modified to MSCAN.
A modern MMSSTV appeared in 2000 with three sequential scans red-green-blue.
STTV Summary:
Symbol Ratemode dependent, 200 – 500 baud (pixels/sec)
ITU-R description1K80F1C or 1K80J3C
Bandwidth1800 Hz
ModulationAnalogue FSK
Average Power100%
Facsimile (FAX) is used mainly by commercial companies for such applications: FAX weather maps and Satellite Images.
HF FAXSummary:
Symbol RateTypically 1000 pixels/sec
ITU-R description2K080F1C or 2K00J3C
Bandwidth2000 Hz
ModulationAnalogue FSK
Average Power100%
Speed60, 90, 120, 180 LPM (120 most common)
IOC288, 576
Advanced Digital Modes
These particular modes are subject for ongoing research and development. They require special and sophisticated hardware and used mainly for military purposes:
PC-ALE
STANAG 4285, 4529
Q15X25
G4GUO has developed a PC version of PC-ALE software. It is most effective for mobile communication networks.
PC-ALESummary:
Symbol Rate125baud
ITU-R description2K25HF1B
Bandwidth2250 Hz
Modulation8-FSK
Average Power100%
ProtocolSynchronous connected ARQ
Synchronous unconnected FEC
Character SetITA2
STANNAG 4285, 4529
These are military standard modem specifications, intended for very high performance on HF. STANAG 4529 is a cut down version of 4285.
Q15X25
While not a communications mode in the conventional sense, exploration of the ionosphere using sounding is an interesting pursuit for Amateurs. The pioneer of this technique for Amateurs is Peter Martinez G3PLX. Developed by Pawel Jalocha SP9VR, Q15X25 (sometimes known as NEWQPSK), is derived from MT63, using a Motorola DSP 56002EVM chip set, may also be used for GPS.
Hardware and Software
My recommendations for PC Interface, in order of preference:
1MyDELCG AntennaSB-2000 Radio Interface
2TigertronicsSignalLink TM USB
3West Mountain RadioRIGblaster Plus
Items 1 and 2 are used mainly in the UK and available from ML&S around £100, you will need interface cables and connectors for your particular rig, at extra cost. (£5 - £45)
Item 3 is also used the UK but mainlyprevalent in the US and available from Waters & Stanton for £135, plus cables etc.
All software to drive your receiver, transmitter or transceiver is provided with the equipment. Care must be taken to choose the correct COM port for the PC. All the interface units have opto-isolation giving high order of interference rejection.
Particular software I use and will describe in the next section.
Designed and developed by Simon Brown HB9DRV
HamRadioDeluxe:
Interface Software to interface TX/RX and PC.
Digital Master DM780:
Includes all the Digital Mode Software used in this document.
Please note. They are both free,also includes Satellite Data.
Modes & Frequencies
Pre programmed Favourites:
Modes, Bands & Frequencies within the DM780 software.
MODES Bands Frequencies (MHz)
Contestia/80 m 3.537000
80 m 3.582 500
40 m 7.038 500
40 m 7.072 500
30 m10.133 000
20 m14.075 000
20 m14.077 000
20 m14.106 000
20 m14.108 000
17 m18.102 000
15 m21.086 000
10 m 28.070 000
CW/ 160 m 1.828 000
CW(KeyCmd)/80 m 3.500 000
CW(WinKey)/40 m 7.000 000
MCW/30 m10.000 000
20 m14.000 000
17 m18.075 000
15 m21.025 000
10 m28.000 000
6 m50.100 000
DominoEx-4/80 m 3.564 000
DominoEx-8/40 m 7.038 000
DominoEx-16/40 m 7.042 000
40 m 7.072 000
30 m10.148 000
20 m14.076 000
20 m14.078 000
Hell/ 160 m 1.804 000
Feld Hell/80 m 3.574 000
Slow Hell/40 m 7.039 000
Feld X5/40 m 7.084 000
Feld X9/30 m10.134 000
Feld 105/20 m14.063 000
Feld 245/17 m18.104 000
Feld 80/15 m21.074 000
(All the MODES are available within these Bands & Frequencies)
Modes & Frequencies Cont.
Pre programmed Favourites:
Modes, Bands & Frequencies within the DM780 software.
MODES Bands Frequencies (MHz)
MFSK-4/ 160 m 1.838 000
MFSK-8/80 m 3.580 000
MFSK-16/40 m 7.037 000
MFSK-32/30 m10.147 000
MFSK-64/20 m14.072 000
20 m14.076 000
20 m14.078 000
17 m18.105 000
15 m21.080 000
15 m21.082 000
15 m21.084 000
12 m24.929 000
10 m28.080 000
10 m28.082 000
10 m28.084 000
6 m50.500 000
Olivia 4/12580 m 3.577 000
Olivia 4/25080 m 3.582 500
Olivia 4/50040 m 7.038 500
Olivia 8/250040 m 7.072 500
Olivia 8/12530 m10.133 000
Olivia 8/50020 m14.075 000
Olivia 8/100020 m14.077 000
Olivia 8/200020 m14.106 000
Olivia 16/200020 m14.108 000
Olivia 32/200017 m18.102 000
Olivia 64/200015 m21.086 500
10 m28.026 000
PSK/ 160 m 1.807 000
BPSK-31/ 160 m 1.838 000
BPSK-63/ 80 m 3.580 000
BPSK-125/40 m 7.040 000
QPSK-31 USB/40 m 7.070 000
QPSK-31 LSB/30 m10.140 000
QPSK-63 USB/20 m14.070 000
QPSK-63 LSB/20 m14.080 000
(All the MODES are available within these Bands & Frequencies)
Modes & Frequencies Cont.
Pre programmed Favourites:
Modes, Bands & Frequencies within the DM780 software.
MODES Bands Frequencies (MHz)
QPSK-125 USB/17 m18.100 000
QPSK-125 LSB/15 m21.070 000
QPSK/ 15 m21.080 000
10 m28.120150
6 m50.250 000
6 m50.285 000
6 m50.385 000
RTTY-45/ 160 m 1.820 000
RTTY-50/80 m 3.580000
RTTY-75/80 m 3.582 000
80 m 3.584 000
40 m 7.040 000
40 m 7.042 000
40 m 7.044 000
40 m 7.080 000
40 m 7.082 000
40 m 7.084 000
30 m10.110 000
30 m10.112 000
30 m10.114 000
20 m14.080 000
20 m14.082 000
20 m14.084 000
20 m14.102 000
20 m14.104 000
15 m21.080 000
15 m21.082 000
15 m21.084 000
12 m24.920 000
12 m24.922 000
12 m24.924 000
10 m28.080 000
10 m28.082 000
10 m28.084 000
6 m50.500 000
(All the MODES are available within these Bands & Frequencies)
Modes & Frequencies Cont.
Pre programmed Favourites:
Modes, Bands & Frequencies within the DM780 software.
MODES Bands Frequencies (MHz)
RTTYM 4/125 80 m 3.577 000
RTTYM 4/25080 m 3.582000
RTTYM 4/50040 m 7.038 000
RTTYM 8/25040 m 7.077 500
RTTYM 8/50030 m10.135 000
RTTYM 8/100020 m14.075 000
RTTYM 8/200020 m14.077 000
RTTYM 16/50020 m14.106 000
RTTYM 16/100020 m14.108 000
RTTYM 32/100017 m18.102 000
RTTYM 32/200015 m21.086 500
RTTYM 64/200010 m28.076 000
SSTV/ 160 m 1.890 000
Martin 1/ 160 m 1.916 000
Martin 2/80 m 3.730 000
Scottie 1/80 m 3.783 000
Scottie 2/80 m 3.845 000
Scottie DX/80 m 3.857 000
P3/ 40 m 7.030 000
P5/ 40 m 7.033 000
P7/40 m 7.045 000
40 m 7.170 000
40 m 7.172 000
20 m14.227 000
20 m14.230 000
20 m14.233 000
20 m14.236 000
17 m18.160 000
15 m21.334 000
15 m21.337 000
15 m21.340 000
15 m21.343 000
15 m21.346 000
15 m21.349 000
(All the MODES are available within these Bands & Frequencies)
Modes & Frequencies Cont.
Pre programmed Favourites:
Modes, Bands & Frequencies within the DM780 software.
MODES Bands Frequencies (MHz)
SSTV/ 12 m24.875 000
10 m28.673 000
10 m28.677 000
10 m28.680 000
10 m28.683 000
10 m28.690 000
6 m50.680 000
THOR 4/ 160 m 1.838 000
THOR 880 m 3.580 000
THOR 16/40 m 7.037 000
Throb -1/30 m10.147 000
Throb -2/20 m14.105 000
Throb -4/17 m18.105 000
Throb X-1/15 m21.080 000
Throb X-2/12 m24.929 000
Throb X-4/10 m28.080 000
(All the MODES are available within these Bands & Frequencies)
Glossory & Software
Glossory
ASKAmplitude shift Keying
AsynchronousGroups of data bits transmitted for Rx-clockto be resynchronised at the start of each group
ARQAutomatic Request Repeat
CRCCyclic Redundancy Check
DPSKDifferential Phase Shift Keying
FECForward Error Correction
FSKFrequency Shift Keying
MCUMulti-mode Control Unit
MFSKMultiple Frequency Shift Keying
PSKPhase Shift Keying
QPSKQuadrature Phase Shift Keying
SynchronousData bits transmitted & recovered using a clock derived from the data stream
TCP/IPTerminal Control Protocol / Internet Protocol
TNCTerminal Mode Controller
VaricodeAlphabet represented by numbers with varying number of bits
Multi-Mode Digital Software
HamRadioDeluxe / Digital Master DM780
MIXW 2TrueTTY HamScopeIZ8BLY Suite
Most of this software is free or shareware for a small fee.Worth a visit for loads of information & free software:
Anyone seriously venturing on trying out ‘Digi-Modes’ I recommend the most complete book yet written on the subject.
DIGITAL MODES For all occasions by Murray Greenman, ZL1BPU
Published by RSGB. (208 pages)
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