I was wondering if it was possible to use SDR as a "ghost box". I personally don't put much stock in them being a connection to the spirit world or whatnot, but I think it would make for a fun project or program. Basically what they do is scan about 15 FM station radio bands per second or something. Is this possible, been thought of or done before? I have seen devices that do this selling for 100 dollars or more on the internet (really!). Any thoughts welcome.