Hi all. Been hacking a bit on rtl_fm again. My repository is at https://github.com/keenerd/rtl-sdr

Pretty much everything has been overhauled. The first year of rtl_fm's life saw a lot of features jammed into dumb places in the code. There was no organization and a lot of problems stemmed from that. Now the code is cleaner, faster and should be much simpler for future features such as multiple dongle/demodulator support.

Major fixes: The most common complaint that people have had is poor selectivity. Rtl_fm was great for strong signals but could not pick up weak signals. This was from shoddy (but very fast) filters. Now there are better filters available. Access them with '-F 0' and '-F 9'. These will use more cpu but still run fine on low end ARMs. There is some more headroom for optimization, but nothing to be premature about. Rtl_power has these same filters if you'd like a visual comparison of how they work.

Due to some stupid misunderstandings on my part, data modes were completely broken. These work again.

New features: You can choose devices by the text in the serial eeprom. This is overloaded onto the existing -d (device index number) option. If it looks like a simple int, do the traditional -d behavior. If it looks like a string, check the eeproms of all devices for exact matches, prefix matches and suffix matches. If your rtl dongles don't have eeproms, my apologies.

Minor improvements: All of the rtl_* utilities have these features, including metric/standard units as well as nearest-gain values and the serial matching.

Going Further: There are also a lot of patches to add various features to rtl_fm. With the new overhaul it should be much easier to add features, but the patches will have to be re-written first. If there are patch sets you you'd to see merged sooner rather than later, please mention them so I can gauge interest.

-Kyle http://kmkeen.com