Slow-Scan Television (SSTV) has been around in ham radio for 50+ years. Initially, SSTV required expensive and complicated equipment, but thanks to computers and today’s digital modes, it’s easier than ever to start experimenting with one of ham radio’s oldest specialty modes!
How do you get started with SSTV? Read on!
What Is SSTV?
SSTV takes a static (non-moving) image and “scans” it from right to left and top to bottom, and transmits the image in three primary colors using audio frequencies (in the same bandwidth as a voice transmission). Because it uses just audio frequencies, any radio that can transmit and receive voice can also transmit and receive SSTV. That means you can use your HF radio, or your VHF mobile, or your VHF HT to send and receive SSTV! There are several popular “modes”, which vary in scan time and image resolution. Needless to say, there is a tradeoff between image speed and resolution – one of the popular modes is “Robot36” which transmits a single image in 36 seconds.
How Do I Get Started?
If you have an interface between your computer and radio for digital modes (FT-8, BPSK, etc.), that interface should work for SSTV. Download and install SSTV software (see right) and configure to see the audio source for your interface. Most software supports “templates” where you can add overlays to images for CQ and your callsign or freeform text.
Even if you don’t have a wired interface, you can still have fun with SSTV. You can use smartphone apps to send and receive SSTV images, just by holding the phone up to your radio microphone or speakers (audio coupling) – it works best in a quiet room.
RWK SSTV Events
SSTV on HF
SSTV is used on all HF bands, but use is concentrated primarily on 20M (14.230MHz), where you can hear activity at all times of the day or night.
SSTV on VHF
SSTV is also possible on VHF/UHF FM (either through a repeater or simplex). You must be aware of the transmit time for images so that you don’t stress or time out your radio (or a repeater). Because it’s FM, SSTV images are fairly clear.
SSTV on the ISS
The International Space Station has SSTV generation capability and periodically will conduct SSTV events. You can obtain a nice certificate from the ARISS project for uploading a received image from the ISS.
Popular SSTV Software
CQ SSTV (iPhone)