Protocol DIGISSTV "Run"
(in PSK63F,PSK220F et PACKET)
DIGISSTV "Run" in
PSK63F and in PSK220F: it is
possible to send and to receive small pictures in digital SSTV ("Run"
protocol), during a QSO in this mode.
This mode is included into the software MULTIPSK by Patrick F6CTE, there is the description of this mode and its variants as well as the specifications coming from his software :
Created by : Patrick Lindecker F6CTE (2005)
It is a digital SSTV protocol
(DIGISSTV), allowing transmission pictures in colors, in grey scale or
in black and white, where the picture may be transmitted among PSK63F,
PSK220F or PACKET text.
The "Run" protocol has several peculiarities:
1) The goal is not, here, to transmit a binary picture of an already compressed file but:
- to load a picture (BMP or JPG) on an array of pixels,
- to compress it in the most appropriate way for radio transmissions,
- to manage its transmission and reception.
2) A SWL or a Ham listening
must be able to decode this digital picture either at the beginning of
the transmission or while the transmission is in progress, hence:
- the lines changes are identified and define the type of compressed picture transmitted (colors, grey scale or black and white),
- the line numbers are transmitted.
So the compression unit chosen here, is the line.
3) In colors and grey scale,
the compression affects very slightly the quality of the picture
(difference between the original and the copy non distinguished without
a precise examination). In black and white, the compression is lossless
4) The picture format is free
but must be comprised between 8x6 and 320x256 (the last one being the
one used in classical analogic SSTV).
5) The chosen compression
method is called RLE ("Run Length Encoding") so the name of this
protocol: "Run". The obtained compression rates are interesting but
modest: typically 3,5 for color pictures, 7 in grey scale, 25 in black
and white, weaker for photographic pictures and bigger for synthetic
pictures. Moreover, the smaller the picture, the weaker the compression
rate, and conversely.
6) To warn the correspondent
Ham or the ones listening, of a picture transmission, the picture is
preceded by a prefix, for example: "Run320x256C" for a color picture in
The general objectives of this
mode and the detailled specifications are given in the document
"RUN_PROTOCOL" situated in the "Specifications" heading on my WEB site
Recommanded frequencies for PSK220F +DIGISSTV "Run" (USB)
Patrick F6CTE proposes to focus calls at the following frequencies and times :
* 14075 Khz (AF around 1000 Hz), at 17h00 UTC if few traffic,
* 10148 kHz (AF around 1000 Hz), at 22h00 UTC if few traffic,
* 144620 kHz (AF around 1000 Hz), at 20h00 UTC if few traffic.
Recommanded frequencies for PACKET 300 bauds + DIGISSTV "Run" (USB)
For the pictures transmission in
DIGISSTV, Patrick F6CTE proposes to focus calls on 14090 Khz USB (AF
around 1000 Hz), at 17h00 UTC if few traffic.
Recommanded frequencies for PACKET 1200 bauds + DIGISSTV "Run" (FM)
For the pictures transmission in DIGISSTV, Patrick F6CTE proposes to focus calls on 144630 kHz at 20h00 UTC if few traffic.