MMSSTV HELP · CHAPTER 04

SSTV Modes

The image formats, resolutions and transmission times supported by MMSSTV.

Classic MMSSTV modes

MMSSTV supports a large collection of analogue SSTV modes. The following table reproduces the mode list from the original Basic Operations documentation.

ModeDurationImage sizeMethod
Robot B/W 88 sec160 × 120Mono tone
Robot B/W 1212 sec160 × 120Mono tone
Robot 2424 sec160 × 120Colour differentiation
Robot 3636 sec320 × 240Colour differentiation
Robot 7272 sec320 × 240Colour differentiation
AVT 9090 sec320 × 240RGB, no sync pulse in image
Scottie 1110 sec320 × 256RGB
Scottie 271 sec320 × 256RGB
Scottie DX269 sec320 × 256RGB
Martin 1114 sec320 × 256RGB
Martin 258 sec320 × 256RGB
SC2-180182 sec320 × 256RGB
SC2-120122 sec320 × 256RGB
SC2-6062 sec320 × 256RGB
PD5050 sec320 × 256Colour differentiation
PD9090 sec320 × 256Colour differentiation
PD120126 sec640 × 496Colour differentiation
PD160161 sec512 × 400Colour differentiation
PD180187 sec640 × 496Colour differentiation
PD240248 sec640 × 496Colour differentiation
PD290289 sec800 × 616Colour differentiation
P3203 sec640 × 496RGB
P5305 sec640 × 496RGB
P7406 sec640 × 496RGB

Historical regional use

Makoto Mori noted that Scottie 1 was widely used in Japan, Scottie 1 and Scottie 2 were common in the United States, while Martin 1 and Martin 2 were commonly used in Europe.

This is a historical observation from the MMSSTV documentation rather than a statement about present-day band activity.

MP modes

MP modes are based on the colour-difference scheme used by PD modes. They were designed to reduce multipath distortion and jitter by using a longer scan time per pixel while compressing colour information along the vertical axis.

ModeSizeVIS
MP73320 × 2562523h
MP115320 × 2562923h
MP140320 × 2562A23h
MP175320 × 2562C23h

MR and ML modes

MR and ML are based on the colour-difference system used in Robot 24 and Robot 72. They were intended to provide good resolution under good conditions, with colour information compressed along the horizontal axis.

ModeSizeVIS
MR73320 × 2564523h
MR90320 × 2564623h
MR115320 × 2564923h
MR140320 × 2564A23h
MR175320 × 2564C23h
ML180640 × 4968523h
ML240640 × 4968623h
ML280640 × 4968923h
ML320640 × 4968A23h

Narrow-band modes

Later MMSSTV versions also included narrow-band MP-N and MC-N modes. Their scan signals occupy approximately 2044 to 2300 Hz and use an extended N-VIS identification scheme.

High-resolution images

Modes such as PD120 through PD290 and P3 through P7 use images larger than the classic 320 × 256 MMSSTV display area. MMSSTV therefore shows a reduced preview while retaining the larger actual image.

The original documentation recommends using templates with dimensions matching the actual image size whenever possible.

Mode data is preserved from the original MMSSTV Basic Operations and MODE.TXT documentation by Makoto Mori, JE3HHT.
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