Packages Qsstv

qsstv

Slow-scan television and radiofax — receive and transmit pictures

• Version recorded: 9.5.8
• Categories: sstv-atv
• Upstream: https://www.qsl.net/on4qz/qsstv/

What it does

Decodes and transmits the analogue SSTV modes -- Martin, Scottie, Robot, PD and the rest -- and the digital DRM-based ones, plus HF radiofax. It finds the mode from the header tone automatically, corrects slant, and keeps a gallery of everything received.

Why you would want it

SSTV is the mode where the result is a picture, which makes it the one people show other people. It is also genuinely useful: the ISS transmits SSTV on 145.800 during scheduled events and a handheld with an antenna is enough to receive it. The radiofax side still carries live weather charts from several stations.

Before it will work

Receiver audio into a sound card, and for transmit, audio out plus PTT through hamlib, flrig or a serial line. The sound card sample rate matters: an uncalibrated card slants the picture, which is what the slant correction exists for.

How it installs

• apt: qsstv

Known problems

Slanted or torn images almost always mean sample-rate error rather than propagation, and the correction has to be done once per machine -- new users blame the band. The Qt5 interface is dense and the mode selector is easy to leave on the wrong setting after a manual decode. Digital SSTV needs both ends to agree and is far less common on the air than the analogue modes.

Keeping it current

• probe: apt policy
• strategy: apt_upgrade

Where to get help with the software itself

Johan Maes, ON4QZ. The project page carries documentation and the source.

Source: catalog/packages/qsstv.yaml