These are my comments on digital communications and are not necessarily all there is to know on the subject. As with everything computer related – there are at least six ways to do the same thing. Given this caveat, let me say this is opinion and not the complete story. I only relate to you my experience of 9 or more years using digital modes and as SATERN International Digital Net Manager to give you the benefit of my experience. I will leave the rest for you to research as you see fit.
MT63 is a text only digital radio modulation mode for use in high noise/high reliability situations. It was developed by Pawel Jalocha, SP9VRC. MT63 is perhaps the most elaborate user of error correction techniques of most ham radio public digital modes. It uses a very efficient error correction method that employes character redundant sequences over several data packets. It has 64 tones spaced 15.625Hz apart, in the 1kHz bandwidth. It is so efficient that even if 25% of the character block sent is obliterated, it will give perfect copy. This method of spreading characters from multiple words over several packets is known generally as Forward Error Correcting (FEC). The FEC error correction employed by MT63 uses a Walsh function that spreads the data bits of each character across all 64 of the tones of the signal spectrum and simultaneously repeats the information over a period of 64 symbols (at maximum interleave) within any one tone. This takes 6.4 seconds. The combination results in good impulse noise rejection. At the same time, in the frequency domain, significant portions of the signal can be masked by unwanted noise or other transmissions without noticeable effect on successful reception. In fact, during tests conducted by MARS, data and voice transmissions were successfully received at the same time within the same audio passband.
Transmission speed is good because there are so many individual tones to describe the information, while the individual symbol rate per tone can remain slow (which is good protection against QRN and most QRM).
When conditions are good and audio bandwidth is not an issue, MT63 (particularly the 2 kHz version) using the “long interleave” setting is the best sub–mode to use. The data rate is good and the compound use of error correction techniques results in a robust broadcast mode readily available to the amateur radio operator. Although it can be a little tricky to identify by ear or on the decoder waterfall, the mode has a fairly generous tolerance to tuning inaccuracies and its immunity to short period impulse noise is superior to most. General wide band noise is also well tolerated as is coherent noise (e.g. a single tone) in band.
Unlike most HF digital modes where a character can be lost or changed into something else, by a single noise burst, MT63 is inherently very robust, because each character (or symbol as it is sometimes referred to) is spread over many tones (to avoid interference such as other radio transmissions) and over several seconds (to avoid short bursts of noise, such as lightning).
MT63’s COFDM like properties
Despite the relatively low data rate, good text speed is maintained, because the text is sent on many tones at once. The system runs at several different speeds, which can be chosen to suit conditions, but 100 WPM is typical in the sub–modes of the widest spectral width (1 and 2k modes).
MT63 sounds unusual, (it sounds like a roaring or buzzing noise) but the performance in the widest spectrum mode is well above normal. It is an asynchronous mode, meaning there is no connection process, as in AMTOR, Packet, PACTOR, or WinMOR. Some users maintain that under poor propagation conditions (namely excessive fading) MT63 works exceedingly well. Under good conditions the performance advantages are less obvious. If the receiver audio passband is of high quality and linear across the entire demodulator audio passband, decoding in high noise situations is of much higher performance. As with other multi–tone modes where many sine waves are transmitted side by side, the transmission audio circuits should be of high quality and with linear gain across the entire audio passband (i.e. no mid–band peaking as with older rigs) to minimize IMD and other passband distortions. The included illustration shows the audio passband spectrum of MT63 in wide band mode. This passband pattern is typical of modern digitally capable ham rigs of medium to high quality.
Performance Comparison With Other Modes
There are disadvantages to MT63. First, the mode is broad and is quite aggressive, (i.e. it causes interference to other modes) but itself is little affected by other modes. MT63 is also far more immune to interference and deliberate “jamming” than any of the more conventional modes. Using the long–interleave option, the spreading is over 64 symbols (6.4 sec latency in 2k mode), with consequent improvement in resistance to impulse and periodic interference, but of course double the time taken for the data to “trickle through” the Walsh encoder and decoder pipeline. Changeover from transmit to receive and vice–versa is therefore considerably slower than most modes due to the data latency in the decoder as the buffers are flushed. It therefore, requires some skill and patience in a QSO as it is not a “break–in” mode as you would think of CW or PSK that have virtually no latency time. Correctly decoded text can take up to 15 seconds to appear on the screen. A clue to synchronized reception can sometimes be gleaned if the software has a digital squelch facility (software based vs. hardware squelch). If the squelch is set up to be closed when no MT63 signal is present, it can often be seen to open as soon as it finds MT63 and ideally the text will follow quite a number of seconds later! In order to make the decoder start printing valid text as soon as possible, software should be chosen that has an effective squelch, so as to minimize feeding the decoder garbage before valid text. Latency in this mode is considerably longer than other 2FSK or multi–AFSK modes like MFSK16 or even MFSK64L. For instance the shortest latency time for MT63 is 3.2 sec. in short interleave 2K transmission mode. The latency time for RTTY is 330 ms. Unlike OLIVIA and MFSK16 the narrower 500 Hz operational modes are much slower using MT63 than the wide (2K) mode. OLIVIA is several times faster and more noise tolerant in the narrow band mode yielding a lower latency, while conversely MT63 becomes much more robust and has a longer latency time in the wide band mode. Accurate text copy can be obtained from MT63–2K when the tones are near or below the noise level under optimal conditions similar to PACTOR III, although at a much lower text throughput.
MARS has adopted MT63 as one of the primary modes for ALE operations between other MARS stations. Alternately, PACTOR II, III and IV are used where available. The fact that MT63 is a common mode for MARS normal digital communication speaks to the reliability and accuracy of this protocol. Military frequencies are not as restrictive (as far as bandwidth goes) as are amateur bands. Nonetheless MT63 can be an important player in emergency communications where adverse conditions exist and where cost may be a factor. Data throughput is well above most keyboard chat modes and exceeds PACTOR I. Partnered with Automatic Link Establishment (or ALE signaling see: www.hflink.com), MT63 serves MARS and many branches of the military as the backbone of their digital network. Currently, it is not a significant player in WinLink 2000 system techniques for obvious reasons.
For the SATERN Digital Net, MT–63 is a definite plus in local nets where the use of low noise frequencies (10 meters and up) are used. Local and regional nets have a significant advantage in throughput when employing MT–63 for message broadcasts. The HF net on 20 meters suffers due to broad variations in band conditions and higher noise figures hampering effective use of MT–63 in the most robust configuration.
In an effort to make sense of the vast selection of software available to ham operators, this session will be devoted to supplying information to help you in deciding what software will best suit your practical situation. Selection of software is highly subjective in that it depends almost entirely on the operator and situation as to which software is appropriate or useful. What we attempt to do here is give the capabilities of software on a comparative basis and allow you to make those choices as needed.
We will group the available applications into three basic catagories:
1) digital text,
2) digital voice,
3) digital image and video.
All software applications mentioned can be used with the computer and soundcard as the modem. Some also allow the use of external computer sound interfaces like the Tigertronics SignaLink modem and West Mountain RigBlaster Advantage, and Timewave Navigator which have a soundcard built in and does not rely on the soundcard in the computer. Off–loading the soundcard duties in this manner increases the efficiency of the interface function several orders of magnitude given the modest cost. The WinLink protocol, WinMOR used the SignalLink interface in the initial testing. Other external hardware is also available from other suppliers.
Some applications also allow external TNC controllers to be used in KISS mode (e.g. the SCS Pactor TNCs). All applications allow cut and paste of messages from one application to the other.
Many of these applications may run under Windows 95, and 98. However, significant sacrifice in performance will be noticed. Some may not work at all if the CPU is too slow. It is recommended that you use a 3rd generation class machine (Intel Celeron, and later) with a CPU of at least 1.2 Ghz or more (preferably 4th generation 2.1 Ghz+ … i3, i5, i7 machines) and no less than 2 Mb memory. This is easily within the range of desktops and laptops available to hams nowadays at low to moderate cost. The soundcard hardware variations are fairly wide between motherboards, lending strength to the argument for the use of the computer interfaces which house internal soundcard hardware. All the applications capable of image transmission should use a 3rd generation class CPU at 2 Ghz or faster with 2 Mb ram; but i3, i5 or i7 6th generation+ CPUs are recommended for best performance.
This popular program contains features which include:
Modes supported by Multipsk:
It is easily noted that this is an impressive list of modes, almost all of which MultiPSK excels. The OLIVIA and CW decoders are among the best around. On the downside, the operator interface takes some getting used to; as can be seen from the image above.
MixW Multimode Terminal
MixW is a multi mode, multi functional software application for every day logging and contests. It has many useful features that make your QSO logging process almost a 100% automatic procedure. MixW may be used with or without an external TNC. The only requirements are a computer running Windows® operating system of various versions (see web site for compatibility) with compatible soundcard and a USB interface. You may download fully functional 15 day trial version of MixW and try it for free. MixW supports different TNCs, antenna rotors, antenna switches, regular and contest logging formats, etc. It also allows using TCP/IP connection over AX.25 packet radio protocol. Some protocols are provided by separately download able plugins (e.g. OLIVIA).
MixW does not attempt to use the text formatting of other applications like FLDIGI or WinMOR for message passing. If FLMSG wrapped messages are received, they may be in the raw text format (compressed or not) and will not appear as sent nor will they be checked for errors (as in FLAMP) other than CRC run-length errors.
MixW is now able to support dual call signs (2). MARS members or another member living in the same household may now use the current version by having a “Dual” registration. MARS members holding a second call sign may now request a new registration file (FREE) by submitting the MARS or family member's call sign for registration. If you are a registered user of MixW software and either hold a MARS call sign or have a member of your family wishing to use MixW who resides in your household (Same Address required). You may request a NEW MixW reg1.dll registration file.
MixW gives you the ability to send and receive RTTY, CW, PSK31, Hellschreiber, MFSK16, FSK31, PSK63, Throb, MT63, SSTV, packet (HF and VHF) and AMTOR. You can also receive PACTOR I and fax with MixW but you cannot send PACTOR I with MixW. MixW will interface to your transceiver if it is CAT/CI-V compatible, which almost all are these days. This means you can manipulate your rig from within MixW with software; you can even do this remotely. MixW can also interface with your antenna rotator if it is designed for computer control.
MixW incorporates a proprietary logging program that includes a “contest mode” with configurations for a number of popular digital contests. When you click on a call sign in the receive window, MixW enters the call into the log and displays the country information according to the prefix.
It is a commercial product by UT2UZ Nick Fedoseev and UU9JDR Fred Nechitailov from Kiev, Ukraine and requires a subscription fee to continue fully functional after the trial period.
DigiPan PSK Terminal
DigiPan stands for “Digital Panoramic Tuning” and brings the ease and simplicity of PANORAMIC reception and transmission to PSK31 and PSK63 operation. DigiPan provides a panoramic display of the frequency spectrum in the form of an active dial scale extending the full width of the computer screen. Depending upon the transceiver IF bandwidth, it is possible to “see” as many as 40 to 50 PSK31 stations at one time. Low-cost transceiver kits for 10–80 meters, the PSK–10, PSK–20, PSK–30, PSK–40, and Warbler (PSK–80), are available from Small WonderLabs that make full use of DigiPan’s panoramic capabilities through the use of a 3000 Hz wideband IF. An article about DigiPan and the panoramic transceiver can be found starting on page 33 of the June, 2000, QST magazine. DigiPan does not decode anywhere close to the number of modes as MultiPSK but it does enjoy a considerably simpler interface; as can be seen in the image above.
MMTTY / MMVARI
Everyday more and more Amateur Radio operators are operating on the HF digital modes, in particular, RTTY (Radio TeleTYpe). RTTY is in common use on emergency nets and for point–to–point Emcomm type message transmission where absolute error–free content is not needed. No matter what your reason might be, it is the purpose of this information to assist getting you started on RTTY.
Even though I’ve been active on RTTY for over 10 years, I don’t claim to have all the answers. I do have a technical background and am familiar with many of the technical aspects of operating RTTY. RTTY is the most fun I’ve had in more than 20 years of Amateur radio. It can be both complicated and simple. So I’ll try to keep things simple.
Anyone can operate RTTY. You don’t have to know how to “touch type” to run RTTY or PSK31. The “hunt & peck” method works fine. Every program I know for RTTY includes special “macros” which hold pre–typed message segments and commands that can be sent by pressing a function key or clicking a button on your screen with a mouse. The late N5JR (SK) was a paraplegic and earned RTTY DXCC before he died (this call has since been re–issued to Joel Rubenstein who is an active RTTY operator too). He operated RTTY with a stick in his mouth. He should be an inspiration to all of us and shows that even those with disabilities can enjoy these very fun and exciting modes. There’s really no excuse not to try.
The most widely used and hailed programs for RTTY and some other digital modes are MMTTY for RTTY and MMVARI for PSK and MFSK digital modes. These are very capable programs from the legendary JE3HHT Makoto Mori. Mori San has provided one of the simplest and most capable applications available today for RTTY, MFSK, and PSK. Both MMTTY and MMVARI have Windows® only programming interfaces that allow these applications to be integrated into programs like logging applications. One such application is Logger32 by Bob Furzer, K4CY. With Logger32, logging automation and soundcard decoding of RTTY, PSK and MFSK is available in an easy to use single interface. The illustrations show MMTTY standalone and MMVARI inside Logger32:
Ham Radio Deluxe / Digital Master 780 (DM780)
Ham Radio Deluxe (HRD) is a suite of free Windows® programs providing computer control for commonly used transceivers and receivers. HRD also includes mapping, satellite tracking and the digital mode program Digital Master 780 (DM780). It is quite attractive, having been written in Microsoft Visual C++ for Windows®. Original versions of this application have been available for many years and were designed and maintained by Simon Brown, HB9DRV. The software has since become a commercial product of HRDSoftware, LLC.
Current version of HRD at this writing is 126.96.36.1990
Minimum Recommended Requirements
Windows Vista® or later – 8GB RAM, 350GB hard drive
storage, Core 2 Duo Processor, 1024x768 256 color display
Windows 7, 10 – 8GB RAM,350 GB hard drive storage, Dual Core Processor, 1920x1080 Hi-Color display
Not available on other Operating Systems.
The heart of Ham Radio Deluxe, Rig Control provides a customize–able interface to control your amateur transceiver using its built–in computer aided control interface. Rig Control allows you to organize buttons, sliders, and drop–downs to toggle radio options, select modes and filter settings, and control various level inputs via your computer screen. HRD Rig Control brings out features buried in a modern rig’s menus, making it easy for you to optimize your rig with a few clicks of the mouse.
Rig Control takes advantage of computer control features built in by your radio’s manufacturer. Using your interface cable, Rig Control takes control of your radio to make the most of its features. It also provides the interface for the other modules of Ham Radio Deluxe to communicate with your radio: bring mode and frequency information straight into your logbook, key your radio while using exciting digital modes, and automatically adjust for Doppler shift while “working the birds.”
Logbook is a complete DX operations center. Beginning with a robust database engine, Ham Radio Deluxe Logbook screams operating convenience. Packed with features, Logbook is the ideal shack accessory for everyone from the novice rag–chewer to the most accomplished paper–hanger. Keep track of all important contact information with the click of a mouse. Look up name, QTH, and other important information about your contacts using a variety of online and offline sources. Interface with the popular QRZ.com call sign database (subscription required), a free look up service, or HRD’s SAM Callsign CD (sold separately.)
Logbook also interfaces with DX Spider cluster servers for spotting the rare ones. The Bandmap feature graphically displays spots within a band with up to 10 bands visible at once. With just a click of a mouse, swing your beam to the DX station’s heading. Once you have the rare DX in the log, integration with Trusted QSL makes uploading to Logbook of the World a snap! Downloading from LoTW is just as simple. In fact, Logbook interfaces with many popular electronic logbook services, including eQSL, HRDLog.net, and ClubLog. Logbook keeps track of many popular awards too. Logbook is packed with features!
Digital Master (formerly DM-780)
Digital Master, formerly “DM-780,” is the all-purpose digital communications package integrated with the Ham Radio Deluxe suite. Digital Master uses your computer’s soundcard interface and radio connection to offer a wide range of communications options to the amateur radio operator. Digital Master is capable of a wide range of digital modes, including CW, RTTY, SSTV, PSK31, MT–63, and more. For the CW enthusiast, Digital Master interfaces with the popular K1EL WinKeyer. True frequency shift keying (FSK) and audio frequency shift keying (AFSK) keying are available for RTTY operation.
You can stay on top of the action with Digital Master’s SuperSweeper, allowing you to copy up to 40 QSO’s at once in CW, RTTY or PSK. Once the QSO is complete, Digital Master interfaces directly with Logbook to record the contact. Digital Master works with a variety of audio and multimode interfaces including the Timewave Navigator, SignaLink USB, and West Mountain Radio RigBlaster.
As is true with MixW, this is a very attractive product with tons of capabilities. However, there is no attempt to process formatted messages as with FLMSG and WinMOR forms.
During our discussion of digital modes we covered the mode MT63 and its’ importance in ham radio. Stream and MT63 terminal are software modems and TNC applications by IZ8BLY, Nino Porchino. Nino has made a very attractive and functional interface that decodes the MFSK8 and MFSK16 modes in the Stream application. He has the MT63 version that decodes MT63 mode as well. They are very similar in appearance and functionality.
The information provided by the interface controls is relevant and helpful. Interface to the rig PTT is via the serial port or computer interface of your choice (e.g. hamlib). While these applications will run on Windows 95 and 98, it is recommended that you use a 4th generation CPU class computer (Intel I–series) with a speed of at least 1.33 Ghz and Windows Vista® or later to avoid speed and lockup problems. Stream and MT63 can run under Linux Wine if the CPU is 3rd generation class or higher running at least 2 Ghz.
For the past 10 years or more, a group of Amateur Radio operators has joined together for communications using Automatick Link Establishmnet (ALE) and Selective Calling. This software and functionality works independently of other software and hardware.
The number of hams has grown from just a handful active in 2001, to the thousands of enthusiasts in it today. Some are following the traditional ham curiosity to explore interesting aspects of communications; others are developing dependable HF nets, or just using it to keep in touch with a circle of ham friends. The need to call up emergency nets or interoperability and liaison with government HF systems has led many hams to adopt the government ALE standard, called FED–STD–1045 or MIL–STD–188–141(a) (b)(c)(plus later notices). This standard caught on slowly in the ham community, initiated by a few operators with limited government surplus gear and some with expensive commercial equipment having embedded ALE or hardware controllers.
Recently, the cost of embedded ALE transceivers has been reduced, and they are now available at similar to the cost of a medium priced ham radio. Also, with ALE software, a ham HF transceiver, a PC computer as the controller, and an appropriate antenna system, hams can harness the power of ALE. The illustration shows a typical EMCOMM message being sent to a specific station using ALE alerting. The annotations explain the many controls and functions of the ALE controller application.
FDMDV is a digital mode voice application on HF – it caters to high quality digital voice under poor band conditions, in only 1100Hz bandwidth!. FDMDV is a digital voice mode intended for transmission and reception over high frequency (HF) radio. It uses a frequency division multiplex (FDM) modem with 15 carriers and no forward error correction (FEC). An open source, low–bit–rate encoder – decoder (CODEC) provides voice quality audio without the listener fatigue caused by noise and interference normally associated with analog single sideband (SSB) voice. Setup and operation of the Windows® only program was developed to make operation straightforward. An HF transceiver, personal computer and soundcard are required. Path simulation and on–the–air HF testing have shown that decoding voice is possible at a signal–to–noise ratio of 3 dB or better. FDMDV is based on ideas by Peter Martinez, G3PLX, and written in C for Windows® by Francesca Lanza, HB9TLK.
It is possible to send and receive FM quality audio on SSB with moderate noise being undetected. This is a semi–secure way to provide high quality voice on HF and VHF SSB. Transmissions on any band from 20 meters to 70cm SSB in 2.5 to 1.1 kc are possible with very high quality. Since the normally analog voice transmissions are digitized, the signal is only intelligible by operators running similar software.
Recent software has been submitted to the Open Source community with an application known as OpenDV or Open Digital Voice. The source code and installable execution modules are available in a variety of platform specific packages online.
D–STAR (Digital Smart Technologies for Amateur Radio) is a digital voice and data protocol specification developed as the result of research by the Japan Amateur Radio League to investigate digital technologies for amateur radio. While there are other digital on–air technologies being used by amateurs that have come from other services, D–Star is one of the first on-air standards to be widely deployed and sold by a major radio manufacturer that is designed specifically for amateur service use. D–Star compatible radios are available on VHF, UHF and microwave amateur radio bands. In addition to the over–the–air protocol, D–Star also provides specifications for network connectivity, enabling D–Star radios to be connected to the Internet or other networks and provisions for routing data streams of voice or packet data via amateur radio callsigns.
The first manufacturer to offer D–Star compatible radios is Icom. As of December 30, 2008, no other amateur radio equipment manufacturer has chosen to include D–Star technology in their radios. In 2011 Kenwood offered re–branded Icom D–Star radios in Japan. Currently this is a hardware–only application, available only from Icom; but is worth mentioning here.
Since leaving “HamPal” (his earlier legacy image file transfer application) Eric, VK4AES has developed a line of programs with the “EasyPal” name. First there was “EasyPal” and “EasyPal Lite”. EasyPal was developed to become “EasyPal Full”. Development of the original “EasyPal” stopped and “EasyPal Full” was called just “EasyPal”. Confused Yet?
EasyPal is still based on hamdrm.dll so is mostly compatible with WinDrm, and HamPal. To remain compatible with the earlier programs the Reed–Solomon encode feature must be switched off. This is done by un–checking the “Encode” box in the preferences. This affects only transmission from EasyPal to the other programs. (if left on, the other station will receive a blank picture file 10KB in size.). “Progressive receive” has been a feature of the EasyPal programs. This enables the receiving station to see the picture gradually appear during reception. Nothing special has to be done at the transmitter for this to happen when all program prerequisites have been met.
Reed–Solomon encoding is an additional form of redundancy to help with unreliable transmission paths (e.g. as on the lower HF bands). The operational price is additional transmission time. A spectrum display is included as well as the waterfall display. This enables an easier check on audio frequency response (the flatter the better, however I have had very good success with my well used TS–440SAT). The RX & TX screens are tabbed for easy switch. A third Tab (View) displays the TX & RX history with options to delete, display full size or send to TX. EasyPal is still experimental but works quite well. High Quality digital images may be sent and received with moderate noise and Doppler shift conditions. Program control allows different transmission modes to increase the noise tolerance under changing conditions. For instance, 40 meters requires the slower configurations while 20 meters and above are quite enough to allow 16 QAM and short interleave operation at a fairly fast transmission rate.
Digital pictures of 640 by 480 may be sent in under 2 minutes. Resolutions of up to 1024 by 780 are allowed (known affectionately as HDSSTV) although with much longer transmission times. Images of strictly black and white (grayscale), rival fax transmission speed with quality rivaling digital copiers. This is a fast and efficient way of sending documents that are otherwise not reproducible using conventional ARRL message handling methods or where short point to point transmissions (e.g. on 10 meters or VHF), of documents do not fit WinLink 2000 use. The only hardware requirements are a computer and soundcard with optional scanning printer and rig interface.
Files types are limited and generally accepted to be of the JPEG
variety. The newer Open JPeg 2000 file type has been added as well.
The non–maintainability of EZPAL and EZPal Lite put into question the longevity of that software. While it is certainly still available and used extensively, there is no way to actively add to, change, or maintain the applicaion. The limited system platform made at least one ham take to creating a compatible Open Source product known as QSSTV.
QSSTV is a program for receiving and transmitting SSTV and HAMDRM
(sometimes called HDSSTV) and authored by Jon Maes, ON4QZ. It is
compatible with most of MMSSTV and EasyPal. This is a truly Open
software application with all source code available for download from
the author’s web site (
It is written in C++ using the Qt Framework...hence the
“Q” in the name.
This author has successfully compiled and ran QSSTV on both Windows® and Linux systems. Binary packages are available for various platforms as well. The images shown are on the Linux Mint 18 platform with a OS X style theme. The QSSTV application runs in native mode for each platform using the resources of the native system without need for emulators or virtual machine environments.
QSSTV attempts to combine MMSSTV and EZPAL modes and features into one application. It does a very nice job of doing so. As can be seen from the images provided here, popular frequencies can yield any image sent by MMSSTV or EZPAL. Operational parameters of each application are recreated in an inovative way by QSSTV. All of the analog SSTV modes and all of the DRM sub-modes are supported by QSSTV.
The distinct advantage of QSSTV is being an all–in–one package. No need to switch back and forth or have two programs running. This one does it all.
X Built In Feature
! May need downloaded module
* With external ALE decode only
** Receive only
+ Using serial port directly
# Using HamLib or RigCAT for radio contol
## Using HRD interface for radio contol
## Using HamLib and CAT/CI-V