SSTV.org.uk

Martin mode

Martin 1

Classic HF color SSTV and compatibility testing.

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, 116.607 s.

M1 SSTV BBC-style colour test card
M1 test card, 320 x 256

Mode spec

Short nameM1
Support statusSupported in app
Spec statusSupported in app; public VIS and timing summary are separated from the app raw timing fields.
Duration114.297 s
Frame320 x 256
Data lines256
Public VISVIS 44 (0x2C)
Standard VIS code0x2C (44)
Extended/N-VISNo
Color modelRGB
Component sequenceG-B-R
Line rate134.387 lpm
Public timing profilePublic Martin M1 timing: VIS 44; 256 lines; 4.862 ms sync at 1200 Hz, 0.572 ms sync porch, Green scan 146.432 ms, 0.572 ms separator, Blue scan, 0.572 ms separator, Red scan, 0.572 ms separator.
App duration114.297 s
App frame320 x 256
App raw VIS0xAC (172)
App timing profileApp RX line fields: sync 5 ms; front porch 0.8 ms; back porch 0.5 ms; separator/blank 0.5 ms; video tones 1500-2300 Hz around 1900 Hz.
App RX sync5 ms
App RX front porch0.8 ms
App RX back porch0.5 ms
App RX separator/blank0.5 ms
App subcarrier1900 Hz
App deviation400 Hz
App tone range1500-2300 Hz

Strengths

  • M1 is a standard-length standard colour Martin mode: 114.297 s, 320 x 256, RGB.
  • M1 keeps the classic Martin G-B-R RGB order, which makes colour order predictable for receivers expecting VIS 44 (0x2C).
  • M1 has explicit app timing fields: 5 ms sync, 0.8 ms front porch, 0.5 ms back porch, 0.5 ms separator/blank, and 1500-2300 Hz around 1900 Hz video tones.
  • M1 has a checked public timing summary plus app timing fields, so the public spec and implementation timing can be compared line by line.

Tradeoffs

  • M1's 114.297 s frame is a balanced choice, but it still needs a stable path for the full 320 x 256 scan.
  • M1 sends colour sequentially in RGB; sync drift can appear as colour fringing before the whole frame becomes unreadable.

Source notes

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