ISS SSTV Decoder

Decode Slow-Scan Television images from the International Space Station. ISS SSTV transmits on 145.800 MHz FM during special events.

Decoder Settings

Resources

ARISS.org (Event Schedule) AMSAT SSTV Guide

About SSTV

SSTV (Slow-Scan Television) is a method for transmitting images via radio. The ISS periodically transmits commemorative images during special events which can be received with an RTL-SDR and appropriate software.

Common modes: PD120, PD180, Martin1, Scottie1

Antenna Guide

2m band (145.800 MHz) — stock SDR antenna will NOT work

V-Dipole (Easiest — ~$5)
  • Element length: ~51 cm each (quarter-wave at 145.8 MHz)
  • Angle: 120° between elements for partial RHCP
  • Orientation: Lay flat, angled toward the ISS pass direction
  • Material: Wire, coat hanger, or copper rod

Same antenna as weather satellites (similar frequency). A QFH or turnstile for 137 MHz also works well here.

Tips for ISS Reception
  • ISS altitude: ~420 km, overhead passes last 5–10 minutes
  • Best passes: Elevation > 30° for clear signal
  • Outdoors: Clear sky view is essential. Roof or open field
  • LNA: Optional but helps — 2m filtered LNA at antenna feed
  • Doppler: ISS moves fast — signal shifts ±3.5 kHz during pass
Quick Reference
ISS SSTV frequency 145.800 MHz
Quarter-wave length 51 cm
Modulation FM (25 kHz)
Polarization RHCP (circular)
Typical pass duration 5–10 min