SSTV Facts and Figures
Some historyAmateur Radio SSTV has a surprisingly long history, going back to the first trials made in the late 1950's and with a notable first transatlantic SSTV contact being made in December 1959 between WA2BCW and G3AST. Commercial systems followed in the 1970's and 1980's, and ham software capable of both receiving and transmitting analog signals followed in the 1990's.
Arriving on the scene in the very early 2000's, digital SSTV was slow to start, but software developments have opened the door to many who are fascinated by the possibility offered by digital SSTV to transmit - on the HF bands! - perfect facsimiles of pictures.
By combining a radio transmitter, computer plus software - components of many radio hams' equipment - and a hardware interface between the two, it has become possible for many to enjoy the possibilities offered by this mode.
SSTV is growing...SSTV has enjoyed an increase in interest recently, due to several factors:
- personal computers are practically universal these days, especially among the ham radio fraternity
- computer-to-transceiver interfaces are readily available and enable the radio ham to send and receive many other digital modes such as PSK, RTTY, Domino, Olivia and Throb to name but a few
- software for analog and digital SSTV, as well as the other digital modes, are available at little or no cost to the user
- the adoption of the many narrow-band SSTV modes currently in use. These allow the transmission of images within a bandwidth of 500Hz, as compared to 2500Hz required by the more traditional wideband modes like Martin and Scottie. A narrower bandwidth means more transmissions can take place in any given sector of a radio band
- the introduction of new digital SSTV modes. These are based on the DRM and permit practically error-free transmission of images, albeit within a bandwidth of 2500Hz or so - comparable to the minimum bandwidth required by a human voice
Where to find SSTV signalsThere are plenty of places where you can find amateur radio SSTV signals. First you need a good receiver capable of tuning around the ham bands, a computer-to-radio interface and a computer with soundcard and software to decode (see below). Try some of these frequencies for starters:
|Band||Frequency||Transmission type||IARU Region|
|80 meters||3730 kHz||wideband analog SSTV||1|
|3733 kHz||digital SSTV||1|
|40 meters||7058 kHz||digital SSTV||1|
|7170 kHz||wideband analog|
|30 meters||10132 kHz||narrowband digital SSTV (MP73-N)||2|
|10144 kHz||narrowband digital SSTV (MP73-N)||1|
|20 meters||14227 - 14230 kHz||analog SSTV|
|14233 kHz||digital SSTV|
|15 meters||21340 kHz||SSTV calling freq.|
|10 meters||28680 kHz||SSTV calling freq.|
|6 meters||50.510 MHz||SSTV (AFSK)|
|2 meters||144.500 MHz||SSTV calling freq.|
Join the clubJoin the World SSTV Club!
How to receive and transmit SSTV signalsYou'll need a receiver and a computer with some kind of soundcard on board, and a radio/computer interface connected to both:
- Receiver - practically any communications receiver or amateur radio transceiver covering the appropriate band will do.
- Computer - any modern PC with Windows, MacOS or Linux would do, providing that the chosen SSTV software (see below) will run. Most often, the onboard computer sound-card will be used by the software to encode/decode the signals, but if the interface (see below) has its' own soundcard, that may be used instead.
- Interface - many commercial radio/computer interfaces are available: see the Links page for further reference. You can also build your own. Some interfaces come supplied with their own soundcard which has been optimized for the types of signals typical of digital radio transmissions - so signal quality will generally be better than if the computer soundcard were to be used.
- Software - a good choice exists, a selection of which may be found in the Links page.
Perhaps the best place to start is on the frequencies 14230 kHz or 14227 kHz, which are arguably the most popular for analog signals. The nearby frequency 14233 kHz is most often used for digital SSTV which is a little more tricky to set up and use.
Depending on the time of day, you may be lucky enough to hear the sound of a SSTV signal shortly after tuning in. Here are a couple of sample SSTV signals from the International Space Station: