Software Defined Radio Software Defined Radios Normally hardware

Software Defined Radio

Software Defined Radios • Normally, hardware takes care of a lot of important radio concepts • • • Amplifying signal Filtering it Choosing a frequency Modulations Decoding • Why not do it in software? • It used to be impossible • Software (processing) abilities couldn’t do it • Enter on a keyboard instead of turning a knob!

What SDR Does • Requires capable hardware • Receive analog signals • Must convert to digital for PC to use! • Amplifying this can be an issue • Lots of places for anomalies • Does have limitations • Sky isn’t the limit • Frequency ranges • Amplitudes

What we have: • Terrible SDR’s • But they work! • And they’re cheap! • Big kid SDRs -> Hundreds to thousands • Receive only, unable to transmit • Meant for watching digital TV • Ironically: I’ve never done this • If we replace the driver, we can do whatever we want

Spectrum • Compatible range: 25 MHz – 1700 MHz • So no wifi sniffing • But other options are out there • Handles around 6 -8 MHz of bandwidth • Can do smaller bands too • Today we’ll aim for FM radio! • Try for NOAA, 162. 525 • Disclaimer: very narrow band, hard to hit • Possibly ADSB, depending on how things go • Disclaimer: Madison, SD isn’t exactly a bustling aviation hub