Category: PlutoSDR

Harvey Mudd College Learn SDR Course with RTL-SDR, PlutoSDR and GNU Radio on YouTube

Professor Jason from Harvery Mudd College in California has recently uploaded a 23 lesson video series on software defined radio digital signal processing (DSP) concepts that can be learned with an RTL-SDR, PlutoSDR and GNU Radio.

If you're looking for a University level introduction to DSP this looks like a good hand on approach to learning. It covers concepts from a simple FM radio receove in GNU Radio, to doppler radar with PlutoSDR, to digital modulation, pulse shaping, GPS reception and more.

All the GNU Radio flowgraphs are available on their class GitHub as well.

Playlist: Learn SDR with Prof Jason

TechMinds: Using a LEO Bodnar GPSDO with a PlutoSDR

Over on the TechMinds YouTube channel Matt has been experimenting with using a PlutoSDR for QO-100 amateur radio satellite communications. The PlutoSDR is a low cost RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range (with mods). The PlutoSDR can suffer from frequency instability, especially when warming up, however on the latest model C/D PlutoSDRs it's possible to inject an external clock signal.

In his video experiment, Matt uses a Leo Bodnar GPSDO as an external clock source. A GPSDO is a "GPS Disciplined Oscillator", as it uses the accurate timing information found in GPS signals to create a high quality clock signal. Matt shows how to set up the GPSDO, and how to tell the PlutoSDR to use the external clock.

He goes on to show the effectiveness of the GPSDO with some transmit experiments.

LEO BODNAR GPSDO With the Adalm Pluto SDR

LimeSDR 2.0 Mini Now Crowdfunding, Standard LimeSDR Discontinued

Back in March we posted about the LimeSDR Mini 1.0 becoming end of life due to component shortages, and a slightly upgraded LimeSDR Mini 2.0 was being planned. The LimeSDR Mini 2.0 has just been released for preorder over on the CrowdSupply crowdfunding website with a price of US$399 + shipping. The first 1000 units are expected to be ready within 14-weeks, with subsequent batches out at 32-weeks.

The new pricing is at quite a premium over the original LimeSDR Mini which released in 2017 for US$139, and the standard LimeSDR which released in 2016 for US$249. However we of course must to take into account the extreme inflation of electronic parts pricing that has occurred over the past few years.

Lime Micro have also noted that the standard LimeSDR has also now been discontinued due to the same supply shortages. The standard LimeSDR had 2x2 RX/TX channels and was capable of a bandwidth of up to 61.44 MHz. In comparison, both versions of the LimeSDR Mini are a 1x1 channel product with 40 MHz of bandwidth.

The LimeSDR Mini 2.0 is almost identical to the LimeSDR Mini 1.0, both still making use of the LMS7002 RF transceiver as the main chip and using the same overall design. The only change is an upgrade to the FPGA, which replaces the Intel MAX 10 16k logic gate FPGA with a significantly more capable Lattice ECP5 44k logic gate FPGA.

Given the new pricing, people on the lookout for a new hacker/research/experimenter SDR in this price range might want to consider this brief comparison to find the best suited SDR for your needs:

  • LimeSDR Mini 2.0 - US$399
    1x1 channels, 40 MHz bandwidth, 10 MHz to 3.5 GHz, 12-bits.
  • HackRF One - US$330 (~$150 clones)
    1x1 channels (half-duplex), 20 MHz bandwidth, 1 MHz to 6 GHz, 8-bits.
  • PlutoSDR - US$229.18
    1x1 channels, 20 MHz bandwidth, 325 MHz to 3.8 GHz, 12-bits.
  • bladeRF 2.0 Micro xA4 - US$540
    2x2 channels, 61.44 MHz bandwidth, 47 MHz to 6 GHz. 12-bits.
The LimeSDR Mini 2.0

Hacking a La Crosse Weather Station with an RTL-SDR, PlutoSDR and Universal Radio Hacker

Thank you to Ryan K for submitting his latest blog post where he gives an in depth explanation of how he reverse engineered his La Crosse weather station using an RTL-SDR, PlutoSDR and the Universal Radio Hacker (URH) software.

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.

Reverse Engineering a La Crosse Weather Station with a PlutoSDR and RTL-SDR

SDRAngel Features Overview: ADS-B, APT, DVB-S, DAB+, AIS, VOR, APRS, and many more built-in apps

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.
  • Airband Voice: Receive multiple Airband channels simultaneously
  • Graves Radar Tracker: For Europeans, track a satellite and watch for reflections in the spectrum from the French Graves space radar. 
  • Radio Clocks: Receive and decode accurate time from radio clocks such as MSF, DCF77, TDF and WWVB.
  • APRS: Decode APRS data, and plot APRS locations and moving APRS enabled vehicles on a map with speed plot.
  • Pagers: Decode POCSAG pagers
  • APRS/AX.25 Satellite: Decode APRS messages from the ISS and NO-84 satellites, via the built in decoder and satellite tracker.
  • Channel Analyzer: Analyze signals in the frequency and time domains
  • QSO Digital and Analog Voice: Decode digital and analog voice. Digital voice handled by the built in DSD demodulator, and includes DMR, dPMR and D-Star.
  • Beacons: Monitor propagation via amateur radio beacons, and plot them on a map.

We note that the video doesn't show the following additional features such as an analog TV decoder, the SDRAngel "ChirpChat" text mode, a FreeDV decoder and several other features.

SignalsEverywhere: Spectrum Analyzer and Tracking Generator with Pluto 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

SignalsEverywhere: Setting up the Retrogram Terminal Spectrum Analyzer for the PlutoSDR

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

Installing Remote SDR V2 on a Raspberry Pi 4B

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.

Over on the programmers blog, F1ATB has put out a new post showing how to install Remote SDR V2 on a Raspberry Pi 4B. The installation has been made simple thanks for a ready to use SD card image.

If you're interested in an overview of Remote SDR V2, we have posted previously about a Tech Minds review of the software.

Remote SDR V2 with a PlutoSDR