Tagged: rtl2832u

SDRSharp Upgraded to .NET5 with New Plugin SDK For Developers

The popular SDR# (SDRSharp) software has recently been updated to version 1788, and now runs on the .NET5 SDK. Most of the upgrades are behind the scenes, but generally the new version appears to be more memory efficient and loads faster. The new version also brings more theme and layout customizations and as explained further below an improved plugin SDK for developers. 

In order to install the latest version you will need to download .NET5 runtime from Microsoft which may not already be on your system. For RTL-SDR users you can then run install-rtlsdr.bat then start the software as usual.

One of the most exciting new developments is the new .NET 5 plugin SDK that is now available. This allows third party developers to easily code up plugins for SDR#. While a plugin SDK already existed before, the new version appears to make development much simpler, and also comes with a few examples to help get developers started quickly. The result is that we should start to see more plugins appearing in the future with more features.

SDR# .NET5 Plugin SDK Example Code

One plugin called Scytale-C for Inmarsat STD-C channel decoding has already been updated to the new SDK. The developer notes that the plugin now works great with the SDR# "slicer" feature, which allows users to decode multiple STD-C signals within the received bandwidth at the same time. 

We've also recently seen reports of Twitter users having success with running this new SDR# version on WINE under Linux. Unfortunately direct USB still doesn't work under WINE, but it would still function via SpyServer or rtl_tcp.

Sparse Array Beamforming with a Phase Coherent 21-Channel RTL-SDR Array

Thank you to Laakso Mikko a PhD student at Aalto University School of Electrical Engineering for submitting news about his research group's latest paper involving a 21-channel phase coherent RTL-SDR system. Laakso writes that he an his colleagues have built a (massive) multichannel receiver array from RTL-SDRs to use in low-budget research. The paper presented at EUSIPCO2020 can be found at IEEE, and for free on their research portal (direct pdf link). The code is also entirely open source and available on GitHub.

Phase coherent SDRs enable interesting applications such as radio direction finding (RDF), passive radar and beam forming.

We introduce a modular and affordable coherent multichannel software-defined radio (SDR) receiver and demonstrate its performance by direction-of-arrival (DOA) estimation on signals collected from a 7 X 3 element uniform rectangular array antenna, comparing the results between the full and sparse arrays. Sparse sensor arrays can reach the resolution of a fully populated array with reduced number of elements, which relaxes the required structural complexity of e.g. antenna arrays. Moreover, sparse arrays facilitate significant cost reduction since fewer expensive RF-IF front ends are needed. Results from the collected data set are analyzed with Multiple Signal Classification (MUSIC) DOA estimator. Generally, the sparse array estimates agree with the full array.

Mikko notes that his next paper on applying deep neural nets to the problem of near-field localization will be presented at this years VTC2021 conference, so we are looking forward to that paper too. 

21 element array connected to a 21-input phase coherent RTL-SDR array

SATSAGEN Spectrum Analyzer Software Updated: Now Supports RTL-SDR

Back in March last year we first posted about the release of SATSAGEN, and program by Alberto (IU1KVL) that allowed the PlutoSDR to work as a spectrum analyzer. SATSAGEN has recently been updated to version 0.5, and it now supports the RTL-SDR, HackRF and Simple Spectrum Analyzer hardware as well. 

Spectrum analyzer software allows you to monitor spectrum activity over a bandwidth much larger than what your SDR supports. It works by rapidly sweeping over multiple frequencies and stitching the spectrum slices together.

Some highlights of the new features include:

  • Works with:
    • ADALM-PLUTO
    • HackRF One
    • RTL-SDR Dongles
    • Simple Spectrum Analyzer series like NWT4000, D6 JTGP-1033, Simple Spectrum Analyzer, and so on.
  • Video trigger, real-time trigger, and fast-cycle feature
  • ADALM-PLUTO custom gain table and Extended linearization table for all devices
  • Transmit from raw format files
  • I/Q balance panel
  • Waterfall
SATSAGEN Interface

Installing and using RTL-SDR and GQRX on a PinePhone

Over on YouTube channel "Privacy & Tech Tips" has uploaded a video demonstrating how it's possible to run GQRX with an RTL-SDR on a PinePhone. In the video the presenter shows how to set up the screen so that GQRX is fully visible, demonstrates GQRX running, and then goes on to show exactly how to install the RTL-SDR drivers on the PinePhone.

The PinePhone is an open source smart phone that can run a full Linux distribution. A PinePhone sells for US$149.99 or $199.99 for a higher end version with more RAM and storage.

RTL-SDR On The Pinephone! Demo, Installation/Hardware

Using 50 Lines of Python Code to Decode NOAA APT Weather Satellite Images

There are already many image decoders for the NOAA APT weather satellites available, with the most common and feature rich program being the abandoned freeware "WXtoIMG".

However many people may not know how simple the APT digital signal processing code is. Over on his blog post Dmitrii Eliuseev explains how only 50 lines of Python code are required to decode an image from received APT audio. Dmitrii's post shows how a Hilbert transform is used on the APT audio which is essentially the entire decoding step. This is then followed by a for loop that calculates the pixel luminosity from the decoded data, and plots it onto an image file. 

Of course the image is only grayscale (or in Dmitrii's case he decided to use greenscale), but adding false color and various other image enhancements found in advanced software like WXtoIMG are just standard image processing techniques.

Dmitrii concludes with the following:

Interesting to mention, that there are not so many operational radio communication systems in the world, the signal of which can be decoded using 20 lines of code. The NOAA satellites are about 20 years old, and when they finally will retire, the new ones will most likely be digital and format will be much more complex (the new Russian Meteor-M2 satellite is already transmitting digital data at 137 MHz). So those who want to try something simple to decode can be advised to hurry up.

[Also mentioned on Hackaday]

Simple decoding of NOAA APT satellites in Python

FAASGS: A Setup to Build a Fully Automatic Amateur and APT Weather Satellite Ground Station

Over on GitHub stdevPavelmc has released his software called FAASGS (Fully Automatic Amateur Satellite Ground Station). FAASGS is an open source program that allows RTL-SDR users to set up a satellite ground station that tunes, record and generate images for NOAA APT weather satellites, as well as records FM amateur radio satellites. The software runs on a single board computer such as a Raspberry Pi, however in the authors own setup he uses an Orange Pi Prime board. The features include:

  • Web interface to see the next passes, the recorded ones, and details for it.
  • Receive any satellite in FM mode (SSB is possible but no there is doppler control yet, so no SSB by now)
  • Record the satellite pass and keep the audio for later.
    • APT WX audio is preserved in wav format and 22050 hz of sampling (the format wximage needs to work with)
    • FM audio satellites is preserved in .mp3 mode but with high quality settings, and other tricks.
      • The spectrogram of the audio is embedded as album art (see below).
      • The pass data and receiving station are stored in the mp3 tags.
  • Automatic decode APT images from WX sats (NOAA 15, 18 and 19)
  • For the voice FM sats we craft a spectrogram and embedd the metadata of the pass on the image
FAASGS main screen showing recordings
FAASGS screen showing an FM amateur radio satellite pass

DragonOS: Decoding FT8 on Linux with WSJT-X

DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR program. The creator of DragonOS, Aaron, uploads various YouTube tutorials showing how to use some of the preinstalled software. This month one of his tutorials covers how to use a SDRplay RSP1A or a HackRF to receive and decode FT8 with the preinstalled software WSJT-X or JS8Call. Aaron also notes that an RTL-SDR could also be used as the SDR.

In the video he covers how to set up a virtual audio cable sink in Linux for getting audio from GQRX into WSJT-X, setting up rigctld to allow WSJT-X to control GQRX, configuring GQRX, CubicSDR and WSJT-X, and finally downloading and using GridTracker.

DragonOS Focal Receive FT8 w/ WSJT-X (RSP1A, HackRF One, GQRX, CubicSDR, GridTracker)

SignalsEverywhere: Installing and Configuring OP25 Phase 1 & 2 Digital Voice Decoder on Linux

In this weeks video Sarah from the SignalsEverywhere YouTube channel show us how to install and configure the OP25 software on a Linux machine. OP25 is a Linux based P25 digital voice decoder which works with RTL-SDR dongles. It is capable of decoding both Phase 1 and Phase 2 systems. Installation is fairly simple via an installation script, but it does take some time to install. After installation Sarah shows how to configure the software in order to properly follow a trunked P25 system. In order to help with importing talkgroup information from a premium RadioReference account Sarah has also created an automatic importer Python script which is very useful.

OP25 Installation and Configuration Tutorial | Setup OP25 P25 Phase 1 and 2 SDR Decoder on Linux Pi