Slow-scan television (SSTV)

Slow-scan television (SSTV) is a picture transmission method used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color. The idea behind recent experiments with narrow band analogue SSTV transmissions is simply an attempt to redefine some common practices among SSTV amateurs. The redefined practices attempt to "fit" SSTV QSOs into the normal operations of the digital radio enthusiasts. PSKers, MFSK operators, and Olivia users are used to navigating a specific section of the bands, and are used to digital rag-chews that exchange signal reports, station info and general operator info (e.g. "been a ham 100 years"). In North America the SSTV enthusiasts have tended to congregate on a couple of frequencies and participate in voice conversations between the sending of pictures. Typical PSKers enjoy QSOs without having to use a microphone. At times, QSOs can be had without disturbing others in the household late at night.

In order for the SSTV signals to be located in the typical PSK31/Olivia/MFSK portions of a band, the SSTV signal must be less than 500 Hz in width. Most common SSTV modes are much wider than this, but lo-and-behold, several hams have recently reminded us that narrow band SSTV has been added to MMSSTV. So now digital radio folks can have SSTV QSOs in the same frequency ranges as their other QSOs. This has a special appeal if you like to use the 30M band. This band, for USA hams, is assigned to CW and Data modes. 30 meter enthusiasts can use narrow SSTV and user "text overlays" to communicate reception reports, QTH, station information, etc.

How these QSOs should be conducted has yet to be firmly established. Some have suggested having the usual PSK/MFSK/DominoEX type QSOs and switching to MMSSTV when a picture needs to be sent. MMSSTV has some interesting abilities where one can actually "keyboard" within the picture. With the concept of "a picture is worth a thousand words" in mind, here is how MMSSTV might be used in narrow mode.

Using a receiver capable of demodulating single-sideband modulation, SSTV transmissions can be heard on the following frequencies:

80 meters 3845 kHz (3730 in Europe) LSB
43 meters 6925 kHz (Pirate Radio) USB
40 meters 7170 kHz (7165 in Europe) LSB
20 meters 14,230 kHz USB
15 meters 21,340 kHz USB
10 meters 28,680 kHz USB
11 meters 27,700 kHz (Pirate Radio) USB

To download the introduction and interface PC please clik: Introduction, Handbook and Interface Schematic
To download the software and user manual please click: MMSSTV & manual, DM780 & manual.

Source :


Pengunjung Online

Ada 7 guests online

Login Anggota