RTL-SDR (Software Defined Radio for Cheap)

One of my favorite little toys has been this cheap $20 USB dongle that was originally designed for over-the-air digital TV reception:

user link on www.amazon.com

This thing doesn't have the best sensitivity and the antenna is primarily intended for UHF frequencies but it's still a very cool gadget.

So, what the heck can you do with this thing?

Using some free software out there (SDR# / SDR Sharp being what I use), this little thing gives you the ability to "see" radio signals in a waterfall display and tune them in for listening.

The concept of software-defined radio is interesting; a portion of radio spectrum is captured and transferred to the computer from the dongle where the software provides a graphical representation of signal strength (typically about 2 MHz of bandwidth at a time) and demodulates the portion of the spectrum that the user selects and tunes. The modulation schemes are all handled in the software (AM, FM, Sideband, etc.).

Again, so what the heck can you actually do with this?

You can listen to lots of different radio signals! While this cheap unit doesn't pick up shortwave or AM bands (the frequency range doesn't go that low), the FM broadcast bands (music) are easily heard as well as air traffic control, the 2 meter and 70 centimeter amateur radio bands, analog police, fire, and emergency radio, and quite a few other radio bands.

If you're a complete dork like I am, you might enjoy playing around with this kind of thing.

Anyone else interested in this stuff?

Damn straight! I have a clunky, older ICOM rig that I listen to radio on. It doesn't support software-defined tuning / demodulation. I'd imagine your computer needs to be kind of powerful to run that well.

One day I'm going to have to pick one of those bad boys up.

The thing about SDR is that it's a ton of fun when you first get it and it's fun to find and test the cool software that's available for it.

After you've tried everything and listened for a while, it gets boring pretty quickly, unfortunately. The sensitivity isn't fabulous but I think a better antenna could change the game considerably.

Listening to ham radio would be nice if more people in my area still talked on the two meter band as much as they did when I first got my ham license.

Those things are fun. I have two of them, one of them I use to listen to police and weather bands and the other one's doing ADSB tracking and logging.

I seen your video about ADSB, real cool!

Oh yeah; I actually hooked mine up again to see if I could track my sister's family's flight as they left for Washington D.C. My antenna's not great so I may have been too far away.

I can pick up quite a few aircraft on a good day.

Sometimes I'll listen to the 2 meter and 70 cm ham bands but I have a Yaesu handheld that does a much better job with that.