What is it?

Software-defined radio is a relatively new wireless technology.

Software-defined radio is also called SDR for short.

SDR uses computer power and software, to replace much of what used to be done by hardware.

What we mean by hardware, is components such as RF Filters, AF Amplifiers, Signal Demodulators etc.


SDR uses a dongle, which plugs into the computer USB port.

The dongle is a device that looks similar to a USB memory stick.

It has an antenna connection on one end.

This is connected to a receiving antenna.

The purpose of the dongle is to receive radio signals.

These signals are then fed into the computer for processing.

There are a number of dongles available, such as the popular RTL-SDR.


Software is used to process and display radio receiver information.

Examples of software for SDR include ‘SDR Console’ and ‘SDRSharp’.


SDR radio is ideal for teaching about radio.

Hardware that would have cost hundreds, can now be replicated in software.

A typical price for an SDR dongle is around £35 pounds.

This combined with free software and an antenna, allows radio reception.

Frequency coverage varies between manufacturers.

Typically 25MHz to over 1500 MHz are tunable.

Published by Craig Miles

Craig Miles

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