These are a great wide band receiver for your PC.
R820T dongle
R820T dongle inside
You can look at up to 2.8MHz of spectrum in real time and decode signals from it, not like most SDR receivers with only a hundred KHz or less bandwidth.
They are very cheap too, available from various places including ebay and cosycave where i got mine.
They have limitations with dynamic range (poor weak signal performance when close to strong signals) but add a little filtering and you will manage just fine.
I have used mine for EME on 1296MHz with great results as long as i have enough gain to lift the noise floor a fair amount then it is just as sensitive as my main radio.
There are a few variants of tuners:
E4000 coverage is 52MHz to 2GHz roughly
R820 coverage is 24MHz to 1.5GHz roughly
Myself i prefer the E4000 tuner variant for most uses as i find there are less spurs and less local pickup from the pc it is running on.
Here are some links to useful rtlsdr resources:
http://osmocom.rtlsdr.org/index.html
http://www.rtlsdr.org/
http://www.reddit.com/r/RTLSDR/
