Martin mode

Martin 3

Martin 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, 59.456 s.

M3 SSTV BBC-style colour test card — M3 source card, 320 x 128

M3 SSTV round-trip decoded test card — Receiver decoded M3 from the FLAC-restored WAV, 128 lines.

Round-trip decode evidence

Encoded, compressed losslessly, restored, then decoded.

The published FLAC is restored to WAV and passed through the SSTV Signal Desk receiver sample harness. The receiver decoded M3 from the FLAC-restored WAV and wrote 128 image lines for this M3 test card.

Open the generated decode report

Mode spec

Short name	M3
Support status	Supported in app
Spec status	Supported in app; public line-level timing was not found in checked sources, so app timing fields are labeled separately.
Duration	57.145 s
Frame	320 x 128
Data lines	128
Public VIS	VIS 36 (0x24)
Standard VIS code	0x24 (36)
Extended/N-VIS	No
Color model	RGB
Component sequence	G-B-R
Line rate	134.395 lpm
Public timing profile	No implementation-grade public line timing was found in checked sources; app implementation fields are listed separately.
App duration	57.145 s
App frame	320 x 128
App raw VIS	0x24 (36)
App timing profile	App RX line fields: sync 4.862 ms; front porch 0.572 ms; back porch 0.572 ms; separator/blank 0.572 ms; video tones 1500-2300 Hz around 1900 Hz.
App RX sync	4.862 ms
App RX front porch	0.5720000000000001 ms
App RX back porch	0.5720000000000001 ms
App RX separator/blank	0.5720000000000001 ms
App subcarrier	1900 Hz
App deviation	400 Hz
App tone range	1500-2300 Hz

Strengths

M3 is a medium-length compact Martin mode: 57.145 s, 320 x 128, RGB.
M3 keeps the classic Martin G-B-R RGB order, which makes colour order predictable for receivers expecting VIS 36 (0x24).
M3 has explicit app timing fields: 4.862 ms sync, 0.572 ms front porch, 0.572 ms back porch, 0.572 ms separator/blank, and 1500-2300 Hz around 1900 Hz video tones.
M3 is documented from the app timing row; the line fields are explicit even where checked public sources do not publish every porch value.

Tradeoffs

M3's 57.145 s airtime is practical for casual contacts, while the 320 x 128 frame still gives less margin than the longer high-detail modes.
M3 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 0x24 and app timing fields are generated from sstv/sstv/sstv/sstvparam.swift during the website build.

SSTV Signal Desk SSTVTableSSTV Signal Desk - accessed 2026-08-24Authority for app-supported mode names and app timing parameters.
SSTV Handbook Chapter 5: List of SSTV modesSSTV Handbook - accessed 2026-08-24Reference for analog SSTV mode names, VIS codes, durations, line counts, column counts, and line rates.