Over on YouTube channel TheSmokinApe has uploaded a video about using RF filters with an RTL-SDR. In the video he first explains why FM bandstop and AM high pass filters might be required when using a software defined radio in order to avoid overloading the SDR with very strong signals. He goes on to test and review our RTL-SDR Blog FM Bandstop and AM Highpass filters, by testing them on a spectrum analyzer.
Back in June of 2014 we posted about the released of a new program called RTLSDR-Airband. RTLSDR-Airband is a Windows and Linux compatible command line tool that allows you to simultaneously monitor multiple AM channels per dongle within the same chunk of bandwidth. It is great for monitoring aircraft voice communications and can be used to feed websites like liveatc.net.
Since our post the development of the software has been taken over by a new developer szpajder, who wrote in to us to let us know that he has now updated RTLSDR-Airband to version 2.0.0. The new versions improves performance and support for small embedded platforms such as the Raspberry Pi 2, but the Windows port is now not actively maintained and probably does not work. The full list of changes is shown below:
- New libconfig-style config file format
- util/convert_cfg: can be used to convert old-style config.txt to the new format
- Syslog logging (enabled by default)
- Daemon mode
- Reworked makefiles, added install rule
- /dev/vcio is now used to access GPU on Raspberry Pi; creating char_dev no longer necessary
- Startup scripts for Debian and Gentoo
- Support for auto gain setting
- Support for multiple outputs per channel
- Support for recording streams to local MP3 files
- Support for ARMv7-based platforms other than RPi (eg. Cubieboard)
- Updated documentation
- Numerous bugfixes and stability improvements
Compilation and install instructions can be found on the projects main GitHub page.
A new command line program for the RTL-SDR called RTL-SDR Airband has recently been released. The program can be used to simultaneously monitor multiple AM channels per dongle. It is intended to be used with online streaming services like liveatc.net which provide live audio streams of air traffic control communications around the world.
Its features include
- Decode multiple AM channels per dongle (within bandwidth frequency range)
- Auto squelch and Automatic Gain Control
- MP3 encoding
- Stream to Icecast or SHOUTcast server
- Low CPU usage on Windows (<4% on i5-2430m) thanks to SSE and AVX instructions
- FFT using GPU on Raspberry Pi (50-55% CPU with default clock)