Over on our Facebook page Micheal Kent has posted about his raspberry pi based RTL-SDR receiver which runs rtl_udp. There’s not much more information on this project, but the video he posted shows what appears to be a Raspberry Pi and RTL-SDR dongle mounted inside an icecream box. There are two knobs mounted on the outside that control the brightness of an LCD screen which shows the tuned frequency, and another knob which controls the frequency itself.
With an RTL-SDR dongle, a cheap $10 modified GPS antenna or 1-2 LNA’s and a patch, dish or helix antenna you can listen to Inmarsat satellite signals, and decode the STD-C NCS channel which contains information such as search and rescue (SAR) and coast guard messages as well as news, weather and incident reports.
Decode POCSAG pager messages with an RTL-SDR. Even in the modern day pagers are still popular with doctors, some fire and ambulance agencies and various service companies, as they tend to be more reliable and have greater coverage.
Follow trunked radio conversations with your RTL-SDR and a program called Unitrunker. Also decode digital communications like P25 and DMR using the Digital Speech Decoder (DSD+) software.
The RTL-SDR software defined radio can be told to run in a mode called “direct sampling mode”, which with a small hardware mod allows the dongle to tune to the HF frequencies where ham radio and many other interesting signals are found. This means that no upconverter circuit is required.
With the right additional hardware, the RTL-SDR software defined radio can be used as a super cheap radio telescope for radio astronomy experiments such as observing the Hydrogen Line and meteor detection.
Digital Radio Monodial (DRM) radio is a type of digital shortwave radio signal that is used by international shortwave radio broadcasters. It provides superior audio quality compared to AM signals by using digital audio encoding. With an upconverter, good antenna, and decoding software the RTL-SDR software defined radio can receive and decode DRM signals.
There are a number of SDRSharp plugins that extend its functionality. Here is a collection of all the plugins and download links that we know of.
The RTL-SDR software defined radio can be used to analyze cellular phone GSM signals, using Linux based tools GR-GSM (or Airprobe) and Wireshark.
By using an RTL-SDR dongle together with a low cost noise source it is possible to measure the response of an RF filter. Also, with an additional piece of hardware called a directional coupler the standing wave ratio (SWR) of antennas can also be measured.
Everyday multiple NOAA weather satellites pass above you. Each NOAA weather satellite broadcasts an Automatic Picture Transmission (APT) signal, which contains a live weather image of your area. The RTL-SDR dongle combined with a good antenna, SDRSharp and a decoding program can be used to download and display these live images several times a day.