More Than Just Software
MMSSTV is a Windows program for receiving and transmitting analogue Slow Scan Television through a computer sound card. It removed the need for expensive dedicated SSTV hardware and gave radio amateurs an accessible way to exchange pictures over the air.
The program became popular because it combined dependable decoding, automatic mode recognition, image preparation, templates, logging, station information and radio control in one practical application.
Although the interface reflects an earlier generation of Windows software, its underlying design remains highly capable. MMSSTV is still used for HF and VHF contacts, demonstrations, special-event stations, contests, image archives and reception of SSTV transmissions from the International Space Station.
Makoto Mori, JE3HHT
MMSSTV was created by Japanese amateur radio operator Makoto Mori, JE3HHT, also known as Mako.
The project began while he was developing a sound-card clock adjustment utility for PSK31 software. That experiment gradually became a complete SSTV application.
His work combined amateur radio experience with digital signal processing, careful timing analysis and an understanding of the practical problems caused by noise, weak signals, multipath and imperfect sound-card clocks.
Much of the English documentation was translated by Nobuyuki Oba, JA7UDE. Other radio amateurs contributed help-file improvements, testing and support, making MMSSTV a true community achievement.
Freeware — Forever
“This program is freeware in version 1.0 and later, forever.”
MMSSTV was released for the benefit of the amateur radio community. The program may be freely copied and redistributed without charging for the software or its documentation, while copyright remains with Makoto Mori.
That decision allowed operators around the world to learn, experiment and participate in SSTV without a software licence fee.
A Program Ahead of Its Time
Automatic Reception
Detects VIS mode signals and can begin receiving automatically.
Signal Processing
Includes AFC, filters, spectrum display, sync analysis and noise-reduction tools.
Slant Correction
Corrects timing errors caused by differences in sound-card sample clocks.
Image History
Stores received pictures and can automatically copy important images to another folder.
Templates and Macros
Adds callsigns, reports, contest numbers, text and graphics to transmitted images.
Logging
Provides callsign search, QSO records, ADIF import and export, and image references.
Radio Control
Supports PTT and radio command functions through serial and compatible interfaces.
Repeater Mode
Can receive, store and retransmit SSTV pictures and send beacon images.
Supported SSTV Modes
MMSSTV supports a broad collection of analogue SSTV modes, from short monochrome transmissions to high-resolution colour pictures.
| Mode family | Examples | Typical use |
|---|---|---|
| Robot | B/W 8, B/W 12, Robot 24, 36 and 72 | Historic and widely recognised colour modes |
| Scottie | Scottie 1, Scottie 2 and Scottie DX | Common in Japan and North America |
| Martin | Martin 1 and Martin 2 | Very widely used in Europe |
| PD | PD50, PD90, PD120, PD160, PD180, PD240 and PD290 | High-quality colour and larger image formats |
| SC2 | SC2-60, SC2-120 and SC2-180 | RGB picture transmission |
| P modes | P3, P5 and P7 | High-resolution RGB images |
| Experimental MM modes | MP, MR, ML, MP-N and MC-N | Improved multipath resistance, resolution or narrowband use |
Receiving SSTV with MMSSTV
Analogue SSTV normally uses audio tones between 1500 and 2300 Hz for image information, with a 1200 Hz synchronization pulse.
Automatic start
With Auto enabled, MMSSTV listens for the VIS signal that identifies the transmitted SSTV mode. It can also analyse the spacing of sync pulses to recognise a picture.
Manual start
When the VIS signal is weak or missed, the operator can manually select the expected mode. Martin 1 and Scottie 1 are useful starting points on many amateur bands.
Slant and phase correction
A picture may lean sideways when the transmitting and receiving sound-card clocks differ. MMSSTV provides automatic, high-accuracy and manual slant correction. Phase adjustment can reposition a picture when synchronization begins at the wrong horizontal point.
Transmitting SSTV
The TX window follows a simple principle: what you see is what you transmit.
Images can be loaded through drag and drop, the Windows clipboard, the built-in stock area, thumbnails or another image-editing program. A template can then add callsigns, reports and other station information.
Select the required SSTV mode, adjust the transmitter audio level carefully and use the TX button to begin. MMSSTV returns to receive after the picture has been sent.
Templates, Macros and the Stock Area
MMSSTV templates can place text, lines, rectangles, colour bars, photographs and other objects over a TX image.
Macros automatically insert information such as a callsign, signal report, contest number or station details. This allows an operator to prepare reusable QSO and CQ templates.
The stock area can hold hundreds of prepared images. Each stock item can preserve both the image and its associated template information, making it quick to select a picture during a contact.
The MMSSTV Logging Utility
MMSSTV includes its own logging system. The active log is stored in an MDT file and can record the callsign, start and end time, reports, QTH, comments and links to received images.
- Callsign search and previous-contact lookup
- QSO start and finish timing
- Editable station and contact information
- Log list, sorting and searching
- ADIF and text import or export
- Contest serial-number support
- Automatic references to received SSTV pictures
- Optional backup copies of the log file
FSKID and Station Identification
MMSSTV can transmit an FSK identification containing the station callsign. The system uses 45.45-baud FSK and may also include a contest number.
Makoto Mori explicitly allowed programmers to implement MMSSTV-compatible FSKID in their own software without requesting permission. This helped make the identification format useful beyond MMSSTV itself.
MMSSTV Repeater Mode
MMSSTV includes an advanced repeater function started with the
-r command-line option.
- The repeater listens for an access tone.
- It answers with a CW identification.
- It waits for an incoming SSTV image.
- The received picture is stored and retransmitted.
- Optional beacon images can be transmitted at intervals.
Templates can add the repeater callsign and timestamp to replayed or beacon pictures. Squelch checking helps prevent transmission while the channel is occupied.
Version 1.13A
MMSSTV 1.13A was released on 29 September 2010. The update corrected sound-card selection problems and included several minor fixes and improvements.
Earlier updates added narrowband SSTV modes, improved AFC, additional radio commands, COM-port selections, logging backups, template tools, DSP improvements, notch filters, LMS modes and many other refinements.
The Original Documentation Collection
The complete MMSSTV package contains far more than a program file. It includes detailed technical and operating documents written by Makoto Mori and translated or expanded by members of the amateur radio community.
Preserving the MMSSTV Legacy
Old software and documentation can easily disappear. Websites close, download links stop working and historic Windows Help formats become inaccessible on modern computers.
The SlowscanTV Information Centre is preserving the knowledge behind MMSSTV by transforming the original documentation into a modern, readable and mobile-friendly online archive.
Future sections will provide detailed guides for installation, receiving, transmitting, templates, logging, radio control, advanced filters, repeater operation and every supported SSTV mode.
“Great software never truly disappears. It lives on through the community that continues to use it.”
— SlowscanTV Information Centre
Thank You, Makoto
SlowscanTV expresses its sincere appreciation to Makoto Mori, JE3HHT, for creating MMSSTV and making it freely available to the worldwide amateur radio community.
We also recognise the translators, testers, help-file editors and radio amateurs whose voluntary work helped MMSSTV reach operators around the world.
Your work continues to bring images, knowledge and friendship across the amateur radio bands.