9 SPECIALIZED COMMUNICATIONS

SLOW SCAN TV/ FACSIMILE

Slow-scan Television (SSTV) is a popular application for transmitting still images over the air, from one station to another. Instead of trying to describe your station, simply showing it is much faster. Transmitting images over the air requires a scan converter, besides a transceiver. A scan converter transforms images taken with a video camera into audio signals that can be fed into your transceiver. The recipient’s scan converter transforms audio signals back into video images so that he or she can view them on a TV set.

Nowadays instead of a scan converter, many hams use a personal computer, a software application, and an interface attached to the transceiver. This is much cheaper, more flexible, and does not require a TV set. In recent years, many low cost digital cameras have become available. You can transfer images from these cameras into your computer.

For further information, consult reference books about Amateur Radio. The frequencies (measured in kHz) commonly used for SSTV operation are listed below:

U.S.A./ Canada

ARU Region 1

(Europe/ Africa)

 

3845, 3857

3730

~ 3740

 

 

 

7171

7035

~ 7045

 

 

 

14230, 14233

14225

~ 14235

 

 

 

21340

21335

~ 21345

 

 

 

28680

28675

~ 28685

 

 

 

145500

 

 

 

 

Fax (facsimile) is one of the original image transmission modes. Using this mode allows you to exchange more detailed graphics than SSTV. Amateur Radio fax functions much like old analog fax systems. It scans paper and converts acquired image data into a series of tones representing white and black portions of the image. Because fax requires longer transmission time, you should use it only when band conditions are stable with strong signals.

Popular fax frequencies include the following:

7245, 14245, 21345 (International Net), and 28945 kHz

Operating on SSTV or fax mainly involves learning the functionality of your computer application or accessory hardware that supports these modes. Consult the instruction manual that comes with your software or accessory equipment.

Note: When operating either SSTV or fax, use a fast AGC setting and switch OFF your Speech Processor, for best results.

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Kenwood TS-480HX, TS-480SAT instruction manual Slow Scan TV/ Facsimile