SSTV stands for Slow Scan Television – it’s not really “television” in the traditional sense, but it’s a way of sending pictures over the radio.
What’s the point of SSTV?
It’s another aspect of amateur radio – the ability to send a picture over our amateur frequencies. The pictures aren’t always great quality, and it can take anything from 30 seconds to a couple of minutes to send an image – but there’s something very rewarding in, say, downloading a picture sent from the International Space Station, or receiving an over-the-air postcard from an amateur round the corner, or round the world.
How do you send an SSTV image?
You’ll need special software on your computer. The software encodes the image, adds your callsign and other text, and turns it into a sound file. The computer then sends that audio file over the air, to be decoded by anyone receiving the signal.
Most amateurs use a rather outdated program called MMSSTV to send and receive images. There’s also software called EasyPal that does a similar job.
What else do I need to know?
There are several different formats used to encode images – Common modes include Martin, Scottie and Robot. Images from the International Space Station tend to be in PD90 format. Some software will automatically detect the format, others have to be set manually
There is a pretty effective app for smartphones and tablets – search for “SSTV” in the Google or Apple app stores.
There are a small number of SSTV repeaters out there – see UK SSTV Repeater Map
Where can I hear SSTV?
- Locally, try the SSTV centre of activity, which is 144.500MHz.
- On HF, try 14.230MHz, which is the 20m SSTV centre of activity (No access to HF? Use a WebSDR!)
- For images from the ISS (only sent occasionally), the usual frequency is 145.800MHz
Sample SSTV Images
The group Essex Ham has created a number of sample SSTV files – if you want to hear what SSTV sounds like, or test out your ability to decode images, try the following mp3 files of SSTV images:
|SSTV: Martin 2 Format||SSTV: Scottie 2 Format|
|Essex Ham 01 Martin2 MP3||Essex Ham 01 Scottie2 MP3|
|Essex Ham 02 Martin2 MP3||Essex Ham 02 Scottie2 MP3|
Links to SSTV beginners articles:
- WA Digital SSTV Group
- SSTV – The Basics (Essex Ham Article)
Got a question about SSTV? Want to share an SSTV tip? Use the comments section below: