Tagged: rtl2832u

Receiving the Chinese Space Station Tiangong-1 with the RTL-SDR

Blogger gat3way has created a post on his blog showing how he was able to receive the Chinese space station Tiangong-1 with the RTL-SDR and a simple cantenna antenna.

The Tiangong-1 station transmits a signal at 2232.15 MHz. To get this signal into a range receivable by the RTL-SDR gat3way used a LNB (Low Noise Block) to downconvert the frequency into one that the RTL-SDR can receive. Using this setup he was able to get a decent signal copy.

Cantenna setup for receiving the Tiangong-1 Chinese Space Station
Cantenna setup for receiving the Tiangong-1 Chinese Space Station

Receiving and Decoding Data from an Esophageal Monitor Inside the Body

Blogger Dolske has recently posted about how he was able to receive and decode signals coming from inside his body. The signals originated from a Bravo Ph Esophageal monitor which is a small wireless sensor that is attached inside your body by a doctor. It is used to monitor pH levels within the body to help diagnose esophageal problems such as acid reflux. The monitor remains in the body for a number of days continually sending data to an external monitoring device which records and logs the pH data.

Bravo pH Esophageal Monitor
Bravo pH Esophageal Monitor

Using his RTL-SDR, Dolse was able to capture the wireless monitors signal using information he found about the monitor online. He found that the monitor used amplitude-shift keying and transmitted at 433.92 MHz. After capturing some signals with the RTL-SDR, he looked at the captured waveform in Audacity and was able to decode a few packets by hand. Finally, he went even further and wrote a Firefox browser based decoder which decodes and displays the pH data on screen.

Web Interface for Showing Decoded pH data from the Esophageal monitor.
Web Interface for Showing Decoded pH data from the Esophageal monitor.

Receiving SO-50 Saudisat 1C with the RTL-SDR

Over on YouTube user Orlando Lima shows reception of the SO-50 Saudisat 1C satellite. Saudisat is an amateur radio satellite with an FM radio repeater. Orlando listened to the downlink frequency at 436.795 MHz using an RTL-SDR, Yagi antenna and Orbitron software to track the downlink frequency in SDR#.

Native RTL-SDR Support Coming to Linux

Linux will soon contain native support for software defined radio devices like the RTL2832U RTL-SDR. These new drivers written by Video4Linux developer Antii Palosaari should be included in the next Linux kernel version 3.15. Antii Palosaari was one of the first people to discover the SDR capabilities of the RTL2832U. In the image below Antii shows SDR# running in Linux with Mono with the Video4Linux gain control screen brought up.

Video4Linux Gain Controls and SDR#
Video4Linux Gain Controls and SDR#

Aircraft Messages with HFDL, MultiPSK and the RTL-SDR

Over on YouTube user k2nccvids has posted two videos showing how he was able to decode High Frequency Data Link (HFDL) packets using the RTL-SDR, Ham-it-up upconverter, MultiPSK and HFDL Display. HFDL is a service similar to ACARS but sent over HF frequencies. It is used to sent short messages to and from aircraft and ground stations.

In the first video k2nccvids uses MultiPSK with the RTL-SDR directly and also uses the add on software HFDL Display to more clearly view received HFDL packets. In the second video he uses SDR-CONSOLEv2 to monitor three HFDL frequencies simultaneously, with MultiPSK and HFDL Display still being used for decoding and display.


Logic Trunked Radio Analyzer and the RTL-SDR

Over on YouTube user k2nccvids has posted a short video showing the Logic Trunked Radio (LTR) Analyzer software working with SDR# and the RTL-SDR. Logic Trunked Radio is a type of radio trunking system that uses distributed control channels modulated into the analogue voice channel instead of using just one signal control channel.

RTL-SDR Tutorial: Following Trunked Radio with Unitrunker

The popular trunking decoding software Unitrunker now supports the RTL2832U R820T RTL-SDR directly in its new version. This means that extra SDR receiver software like SDR# is no longer required to use Unitrunker.

You can download the latest version of Unitrunker here. (NOTE: Unitrunker has recently been updated to V2.1 and so the tutorial below may look a little different now)

In a normal radio system, one company (or talkgroup) might use a single frequency for radio communications. However, this is very inefficient as the frequency may not be in use for the majority of the time. In a trunked radio system, a small set number of frequencies are shared between a large number of talkgroups. Each radio receives a special computer controlled control channel. The control channel determines a vacant frequency that a particular talkgroup should use. This helps to make radio frequency allocations more efficient.

Because a talkgroup might switch between various frequencies often, it can make listening to a conversation difficult for radio scanners. Unitrunker can be used to decode the control channel and follow a voice conversation as it hops across various frequencies. With two RTL-SDR dongles you can set up a trunking receiver station with just Unitrunker. What follows below is a tutorial on how to set this up.

Continue reading →

Decoding a Weather Temperature Sensor with the RTL-SDR and GNU Radio

Over on YouTube user MrCircuitMatt has uploaded two videos on how he was able to decode a temperature weather sensor using an RTL-SDR and GNU Radio. His videos go through the GNU Radio technical steps as well as the signal encoding theory he used to decode the temperature.

Using RTL-SDR to read temperature from outdoor sensor, part 1

Using RTL-SDR to read temperature from outdoor sensor, part 2