Page Title: Misc - SDR What Is
Last Modified: 2026-07-01 07:12:08
Current Date: 2026-07-22 11:27:01 UTC
Software Defined Radio (SDR) is based on the concept of replacing traditional analog radio components with digital signal processing algorithms that are then implemented in software.
RTL-SDR is a tiny, low-cost USB dongle that turns your computer into a listening device for the radio signals in the air. Depending on the model, it can tune from 500 kHz to as high as 1.75 GHz. Its companion software is largely shaped by the community and offered freely. One key truth, though: RTL-SDR can receive, not transmit.
Its beginnings are written in repurposed hardware of the mass produced DVB-T TV tuner dongles built on the RTL2832U chipset. Through the combined work of Antti Palosaari, Eric Fry, and Osmocom (especially Steve Markgraf), a door was opened when they found the RTL2832U’s raw I/Q data could be reached directly. With that access, the DVB-T tuner could be transformed by Steve Markgraf’s custom software driver into a wideband software defined radio.
Since its discovery, RTL-SDR has grown into something remarkably widespread, breaking open the radio spectrum as if it were a locked gate. Now even budget minded hobbyists and anyone curious enough can step through and listen. A few years ago, this kind of SDR ability would likely have cost hundreds, even thousands of dollars. You may also hear it called RTL2832U, DVB-T SDR, DVB-T dongle, RTL dongle, or the 'cheap software defined radio.'
The SDR that I use is the RTL-SDR V3 that uses a RTL2832U chipset with the SDR# (SDR Sharp) software with is free to use.
For more information about SDR then take a look at...
Big list of RTL-SDR supported-software/
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