The La Crosse weather station system consists of a LCD base station, and various wireless sensors. Ryan first discovered that the devices used the 915 MHz frequency band via details written on the device itself. His next step was to open up Universal Radio Hacker and use one of his SDRs to record a packet. URH then allowed him to convert that data into bits for packet analysis. The rest of his post goes into detail on how he set the symbol rate, discovered the preamble and reverse engineered the CRC code.
The next step he took was to generate a spoofed packet generated by URH and transmitted by the PlutoSDR. This allowed him to set the base station display to any temperature that he specified. But he ran into a problem where only the first packet he sent after power up was received. Eventually he discovered that the system sets a randomized interval for each of the transmitters at startup, and data outside of that interval is ignored.
Ryan's post explains his whole though process and progress in detail, so is an excellent study for anyone looking to get into reverse engineering wireless signals.
SDRAngel is a general purpose software defined radio program that is compatible with most SDRs including the RTL-SDR. We've posted about it several times before on the blog, however we did not realize how much progress has occurred with developing various built in plugins and decoders for it.
Thanks to Jon for writing in and sharing with us a demonstration video that the SDRAngel team have released on their YouTube channel. From the video we can see that SDRAngel now comes stock with a whole host of built in decoders and apps for various radio applications making it close to an all-in-one SDR platform. The built in applications include:
ADS-B Decoder: Decodes aircraft ADS-B data and plots aircraft positions on a map
NOAA APT Decoder: Decodes NOAA weather satellite images (in black and white only)
DVB-S: Decodes and plays Digital TV DVB-S and DVB-S2 video
AIS: Decodes marine AIS data and plots vessel positions on a map
VOR: Decodes VOR aircraft navigational beacons, and plots bearing lines on a map, allowing you to determine your receivers position.
DAB+: Decodes and plays DAB digital audio signals
Radio Astronomy Hydrogen Line: With an appropriate radio telescope connected to the SDR, integrates and displays the Hydrogen Line FFT with various settings, and a map of the galaxy showing where your dish is pointing. Can also control a dish rotator.
Radio Astronomy Solar Observations: Similar to the Hydrogen line app, allows you to make solar measurements.
Broadcast FM: Decoding and playback. Includes RDS decoding.
Noise Figure Measurements: Together with a noise source you can measure the noise figure of a SDR.
In the latest video on the Signals Everywhere YouTube channel, Sarah investigates how a PlutoSDR can be used as a Spectrum Analyzer with the SATSAGEN software. The SATSAGEN software is able to work as a spectrum analyzer by rapidly sweeping over multiple frequencies and stitching the spectrum slices together. It support SDRs like the HackRF, PlutoSDR and RTL-SDR (in receive mode only). The PlutoSDR can transmit, so it is able to work as a full spectrum analyzer with tracking generator, allowing users to measure RF devices such as filters, tune antennas, and work as a frequency generator.
In the video Sarah demonstrates how to use the PlutoSDR and SATSAGEN to measure our RTL-SDR Blog Broadcast FM filter, and to tune our multipurpose dipole antenna.
Spectrum Analyzer and Tracking Generator with Pluto SDR
This week on the SignalsEverywhere YouTube channel Sarah shows how to install the "Retrogram" software. This is a command line 'retro' styled spectrum analyzer designed to be used with the PlutoSDR. The software makes use of ASCII art to display the spectrum, meaning that a spectrum can be viewed directly in an SSH terminal, without any GUI.
In the video Sarah goes through the steps to install the software before demonstrating it in action.
Retrogram - A Command Line Spectrum Analyzer For The PlutoSDR
Remote SDR V2 is software that allows you to easily remotely access either a PlutoSDR, HackRF or RTL-SDR software defined radio. It was originally designed to be used with the amateur radio QO-100 satellite, but version 2.0 includes multiple demodulation modes, NBFM/SSB transmission capability, CTCSS and DTMF encoders, modulation compression and a programmable frequency shift for relays.
MMDVM is firmware that normally runs on an ARM microcontroller board such as the Arduino Due, and is designed to be interfaced with hardware radios via the microcontrollers built in ADC and DAC hardware.
In order to use an SDR instead of physical hardware radios, Adrian's article describes how a fork of MMDVM called MMDVM-SDR is used in his system as this allows the code to run on a normal Linux computer with an SDR. GNU Radio running on Adrian's own QRadioLink software is then used to create software ADC/DAC interfaces for the SDR and MMDVM-SDR to interface with, as well as providing a user interface.
Over on YouTube Aaron has uploaded a video showing how he is using the SDR4Space.lite package in DragonOS to do some interesting experiments with automated spectrum analysis using a PlutoSDR or RTL-SDR. As a reminder, Aaron is responsible for DragonOS which is a Linux OS with many SDR software programs preinstalled (including SDR4Space.lite).
Any of these scripts can be modified, new ones can be built, and cron jobs or other scripts could call upon them as needed. I hope to do more videos once I figure out how to take the data and put it into some sort of database.
DragonOS Focal Automate Spectrum Analysis + IQ recording w/ SDR4space.lite (RTLSDR, PlutoSDR) part 1
The "Pluto Plus" (aka Pluto+) is an unofficial and upgraded version of the Analog Devices ADALM Pluto SDR. It is currently available on Aliexpress and Banggood stores. In his latest video Tech Minds reviews a Pluto+ SDR that he has received, noting that it has all of the features that should have been in the original Adalm PlutoSDR.
He notes that the PlutoSDR+ has various improvements over the PlutoSDR such as that it comes in a metal enclosure, has four SMA connections (2x TX, 2x TX), a Gigabit Ethernet connection, a microSD slot, external clock input, 0.5PPM TCXO, fine tunable clock via resistor, a PTT key port and a DFU key.
In the video he goes on to show how to set up the PlutoSDR+ before testing it out on a QO-100 satellite setup, noting that it works perfectly and without any signal drift noticed.