SSTV.org.uk

Robot mode

Robot 36

Fast color SSTV, commonly associated with public ISS SSTV reception.

Supported in app

Mode sample

BBC-style colour test card and app-generated audio

The image is generated locally for this mode's raster. For supported modes, the audio sample is encoded from that image with the SSTV Signal Desk transmitter code, then published as lossless FLAC for static playback.

FLAC, 48 kHz, 16-bit mono, 38.315 s.

R36 SSTV BBC-style colour test card
R36 test card, 320 x 240

Mode spec

Short nameR36
Support statusSupported in app
Spec statusSupported in app; public VIS and timing summary are separated from the app raw timing fields.
Duration36.002 s
Frame320 x 240
Data lines240
Public VISVIS 8 (0x08)
Standard VIS code0x08 (8)
Extended/N-VISNo
Color modelYCrCb
Component sequenceY-RY-BY
Line rate399.978 lpm
Public timing profilePublic Robot 36 timing: VIS 8; 240 lines; 9.0 ms sync, 3.0 ms sync porch, 88.0 ms Y scan, alternating 1500 Hz and 2300 Hz separators, 1.5 ms porch, and 44.0 ms R-Y or B-Y chroma scans.
App duration36.002 s
App frame320 x 240
App raw VIS0x88 (136)
App timing profileApp RX line fields: sync 9 ms; front porch 0.4 ms; back porch 2.5 ms; separator/blank 7 ms; video tones 1500-2300 Hz around 1900 Hz.
App RX sync9 ms
App RX front porch0.4 ms
App RX back porch2.5 ms
App RX separator/blank7 ms
App subcarrier1900 Hz
App deviation400 Hz
App tone range1500-2300 Hz

Strengths

  • R36 is a fast standard colour Robot mode: 36.002 s, 320 x 240, YCrCb.
  • R36 uses Y-RY-BY colour-difference scanning; the VIS 8 (0x08) row keeps luminance separate from alternating chroma information for Robot-family compatibility.
  • R36 has explicit app timing fields: 9 ms sync, 0.4 ms front porch, 2.5 ms back porch, 7 ms separator/blank, and 1500-2300 Hz around 1900 Hz video tones.
  • R36 has a checked public timing summary plus app timing fields, so the public spec and implementation timing can be compared line by line.

Tradeoffs

  • R36's 36.002 s airtime is practical for casual contacts, while the 320 x 240 frame still gives less margin than the longer high-detail modes.
  • R36 colour-difference coding can preserve useful luminance detail, but chroma edges may look softer than full-rate RGB modes after weak-path reception.

Source notes

Public VIS/timing labels are normalized from checked SSTV references where available. App raw VIS 0x88 and app timing fields are generated from sstv/sstv/sstv/sstvparam.swift during the website build.