Articles

Software-Defined Radio (SDR) has revolutionized Amateur Radio, offering powerful capabilites for the fraction of the cost of traditional hardware. One of the easiest ways to explore SDR is with a low-cost dongle. Why Start with a Low-Cost SDR Dongle? Low-cost SDR dongles, often based on the RTL2832U or R820T chipsets, are USB devices that can receive a wide range of frequencies. They were originally designed for digital TV but quickly gained popularity in the amateur radio community due to their affordability and wide range of applications.

SSTV usually only takes up to a maximum of 3 kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame. Since SSTV systems operate on voice frequencies, amateurs use it on shortwave (also known as HF by amateur radio operators), VHF and UHF radio. SSTV uses analogue frequency modulation, in which every different value of brightness in the image gets a different audio frequency.