This is an excellent application; specifically it does exactly what it claims to do whereas the commercial program, Touchstone Pro, is seriously broken. I did have installation problems and it took a lot of effort to get around that, but the author was helpful. I got into this low-cost spectrum analyzer thing because a client of mine wants to reduce the EMI (electro-magnetic interference) from a product I designed. He did not fund an EMI study in the first place and is reluctant to spend money now on equipment, but I hate just guessing so I'm trying to put together a simple EMI evaluation setup on my own nickel. I started with RF Viewer and Touchstone Pro from NutsAboutNets. To cut a long story short, Touchstone Pro is making some bad mistakes in the signal processing and the output spectrum is polluted by artifacts that are not actual input signals. I discovered this when I found RTLSDR Scanner, which produces a spectrum that I can explain in every detail. It is well known that the Realtek RTL2832U hardware dongle produces signals at 28.8 MHz and its harmonics and I can see these clearly. I can also see the radio stations in the FM broadcast band and there's nothing I can do about that without a radio-proof room. Otherwise, what I'm seeing makes sense in terms of the experiments I'm carrying out, which wasn't the case with Touchstone Pro. RTLSDR Scanner is under active development and it has a few rough edges that I won't go into because they'll probably be fixed by the time anyone reads this. Its basic feature set is pretty much what I need, plus stuff that I don't need but you might. If you decide to buy a dongle and try this out, note that scanning and producing a spectrum is slow. This is a limitation of the dongle and not the software, so don't be critical of RTLSDR Scanner because it's slow. Same thing with the lower and upper frequency limits. If you want anything much better than this you're going to have to spend about 1,000 bucks, so keep that in mind. I'll be sending the author 50 bucks, about what I wasted on Touchstone Pro, and I suggest you do the same. The world needs software like this.
I like this app, I just wish it had the ability to set the range to sub-Mhz. For example I'd like to be able to scan 55.230 - 55.270 Mhz and not waste time scanning from 55-56 Mhz. An chance of this being possible?