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Wraase mode

Wraase SC2 180

Wraase 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, 184.349 s.

SC2-180 SSTV BBC-style colour test card
SC2-180 test card, 320 x 256

Mode spec

Short nameSC2-180
Support statusSupported in app
Spec statusSupported in app; public VIS and timing summary are separated from the app raw timing fields.
Duration182.038 s
Frame320 x 256
Data lines256
Public VISVIS 55 (0x37)
Standard VIS code0x37 (55)
Extended/N-VISNo
Color modelRGB
Component sequenceR-G-B
Line rate84.378 lpm
Public timing profilePublic Wraase SC2-180 timing: VIS 55; 256 lines; 5.5225 ms sync, 0.500 ms porch, then Red, Green, and Blue scans.
App duration182.038 s
App frame320 x 256
App raw VIS0xB7 (183)
App timing profileApp RX line fields: sync 5 ms; front porch 1 ms; back porch 1 ms; separator/blank 1 ms; video tones 1500-2300 Hz around 1900 Hz.
App RX sync5 ms
App RX front porch1 ms
App RX back porch1 ms
App RX separator/blank1 ms
App subcarrier1900 Hz
App deviation400 Hz
App tone range1500-2300 Hz

Strengths

  • SC2-180 is a long-form standard colour Wraase mode: 182.038 s, 320 x 256, RGB.
  • SC2-180 uses R-G-B RGB component order and VIS 55 (0x37), giving receivers enough mode identity to separate it from neighbouring Wraase rows.
  • SC2-180 has explicit app timing fields: 5 ms sync, 1 ms front porch, 1 ms back porch, 1 ms separator/blank, and 1500-2300 Hz around 1900 Hz video tones.
  • SC2-180 has a checked public timing summary plus app timing fields, so the public spec and implementation timing can be compared line by line.

Tradeoffs

  • SC2-180's 182.038 s transfer can carry more picture detail, but it occupies the channel longer and is less forgiving of fades across the 320 x 256 frame.
  • SC2-180 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 0xB7 and app timing fields are generated from sstv/sstv/sstv/sstvparam.swift during the website build.