Re: who uses an RTL dongle for SDR?
I have used the RTL dongle quite extensively for ham radio listening and as a spectrum analyser for work.
There is lots of reading on the net, these things are great. There are some Russian DLL files about that allow it to work lower, I have had mine working reasonably successfully on 40m. If you bypass the tuner chip, I believe it will work lower, with obvious lack of selectivity, which is of course, it's Achilles heel anyway.
Many basic SDRs out there have these at their core, with additional circuitry, especially front end.
I recommend everyone to have a go with one, as they are beer money items, you will be pleasantly surprised.
If in any doubt go onto the hack green SDR, it's bult with RTL dongles.
http://hackgreensdr.org:8902/