SSTV.org.uk

Robot mode

Robot 72

Robot family analog SSTV operation and compatibility reference.

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, 74.315 s.

R72 SSTV BBC-style colour test card
R72 test card, 320 x 240

Mode spec

Short nameR72
Support statusSupported in app
Spec statusSupported in app; public VIS and timing summary are separated from the app raw timing fields.
Duration72.005 s
Frame320 x 240
Data lines240
Public VISVIS 12 (0x0C)
Standard VIS code0x0C (12)
Extended/N-VISNo
Color modelYCrCb
Component sequenceY-RY-BY
Line rate199.986 lpm
Public timing profilePublic Robot 72 timing: VIS 12; 240 lines; 9.0 ms sync, 3.0 ms sync porch, 138.0 ms Y scan, 4.5 ms separators, 1.5 ms porches, and 69.0 ms R-Y and B-Y scans.
App duration72.005 s
App frame320 x 240
App raw VIS0x0C (12)
App timing profileApp RX line fields: sync 9 ms; front porch 0.4 ms; back porch 3.5 ms; separator/blank 6 ms; video tones 1500-2300 Hz around 1900 Hz.
App RX sync9 ms
App RX front porch0.4 ms
App RX back porch3.5 ms
App RX separator/blank6 ms
App subcarrier1900 Hz
App deviation400 Hz
App tone range1500-2300 Hz

Strengths

  • R72 is a medium-length standard colour Robot mode: 72.005 s, 320 x 240, YCrCb.
  • R72 uses Y-RY-BY colour-difference scanning; the VIS 12 (0x0C) row keeps luminance separate from alternating chroma information for Robot-family compatibility.
  • R72 has explicit app timing fields: 9 ms sync, 0.4 ms front porch, 3.5 ms back porch, 6 ms separator/blank, and 1500-2300 Hz around 1900 Hz video tones.
  • R72 has a checked public timing summary plus app timing fields, so the public spec and implementation timing can be compared line by line.

Tradeoffs

  • R72's 72.005 s airtime is practical for casual contacts, while the 320 x 240 frame still gives less margin than the longer high-detail modes.
  • R72 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 0x0C and app timing fields are generated from sstv/sstv/sstv/sstvparam.swift during the website build.