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SSTV ("Slow Scan Television") allows the user to send fixed pictures (in general in colors), with a bandwidth similar to the one of HF Fax ( shift of 800 Hz, white at 2300 Hz and black at 1500 Hz). Different SSTV modes are proposed,
The SSTV ("Slow Scan Television") allows the user to send fixed pictures, in colors or in grey scales, with a transmission band similar to the one of HF Fax ( shift of 800 Hz, the white at 2300 Hz and the black at 1500 Hz). Different SSTV modes exist.
SSTV is, as Fax mode, an analog mode, not a digital mode.
In SSTV "grey scales" (as in B/W24), frequencies are situated between 1500 and 2300 Hz from the black (1500 Hz) to the white (2300 Hz). In a color picture, the
grey nuance is defined as equal to the mean value between the three fundamental color levels (green, red and blue).
* the VIS code for B/W24: this binary code allows to define the used mode. It is available for classical modes as Martin 1 or Scottie 1. The bit "0" is defined by a frequency of 1100 Hz and the bit "1" by a frequency of 1300 Hz. Therefore starting from a state when the mode is unknown, the VIS code will allow to define it.
* a synchronization signal of 7 ms long at 1200 Hz,
* a transmission of 93 ms long to define the grey level.
* this process is repeated (synchronization then grey level) for each of the 240 lines. So the transmission of a picture is 24 seconds long.
In SSTV "color" (as in Martin1), the color of each pixel is defined from the fundamental colors, the proportion of each of these three components allows to define a big number of colors (256x256x256).
The modes proposed by the author are the following:
* Martin 1: color mode, transmission time: 114 sec,
* Martin 2: color mode, transmission time: 58 sec,
* Scottie 1: color mode, transmission time: 110 sec,
* Scottie 2: color mode, transmission time: 71 sec,
* Scottie DX: color mode, transmission time: 268 sec,
* Robot 36: color mode, transmission time: 36 sec,
* Robot 72: color mode, transmission time: 72 sec,
* B/W 24: grey scales mode, transmission time: 24 sec,
* PD 50: color mode, transmission time: 50 s,
* PD 90: color mode, transmission time: 90 s,
* PD 120 (RX only): color mode, transmission time: 126 s,
* PD 180 (RX only): color mode, transmission time: 187 s,
* PD 240 (RX only): color mode, transmission time: 248 s,
* SC2 180: color mode, transmission time: 182 s.









Mode Menu
SSTV
Mode Audio Sample
FFT Window Screenshot
sstv