SSTV
Slow-Scan Television (SSTV) refers to any method of sending pictures over amateur radio. Although the vast majority of SSTV activity today uses computers for modulation and demodulation (similar to many digital modes), most SSTV modes are technically analog.
A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6 MHz wide channels, because it transmits 25 or 30 picture frames per second, but SSTV usually only takes up to a maximum of 3 kHz of bandwidth. It is a much slower method of transmission than broadcast television, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame. Because of this, it is used for still images, not video.
Since SSTV systems operate on voice frequencies, amateurs use it on HF, VHF and UHF radio.
A modern system, having gained ground since the early 1990s, uses a personal computer and special software in place of much of the custom equipment. The sound card of a PC, with special processing software, acts as a modem. The computer screen provides the output. A digital camera or saved digital photos provide the input. Even more recently, it is possible to use a smartphone or tablet for SSTV. This can be very convenient, because the camera is integrated into the device and can be easily moved and pointed.
Samples
Robot
Robot 36
36 seconds per picture
Robot 72
72 seconds (1 minute 12 seconds) per picture
Scottie
Scottie 1
Scottie 2
Scottie DX
Martin
Martin 1
Martin 2
PD
PD 50
50 seconds per picture
PD 90
90 seconds (1 minute 30 seconds) per picture
PD 120
120 seconds (2 minutes) per picture
PD 160
160 seconds (2 minutes 40 seconds) per picture
PD 180
180 seconds (3 minutes) per picture
PD 240
240 seconds (4 minutes) per picture
PD 290
290 seconds (4 minutes 50 seconds) per picture Template:WikipediaCopyright
