Tagged: d-star

SDRangel Now Available on Android: Mobile ADS-B, AIS, APT, Digital Voice, POCSAG, APRS, RS41 Radiosonde Decoders

SDRangel is a free open source software defined radio program that is compatible with many SDRs, including RTL-SDRs. SDRAngel is set apart from other programs because of it's huge swath of built in demodulators and decoders.

Thank you to reader Jon for writing in and noting that SDRangel has recently been released for Android as a free Google Play download. This is an amazing development that could open up many doors into portable decoding setups as the Android version supports almost every decoder implemented on the desktop version. Jon writes:

It includes most of the functionality of the desktop version of SDRangel, including:

  • AM, FM, SSB, Broadcast FM and DAB, AIS, ADS-B, Digital Voice (DMR, dPMR, D-Star, FreeDV), Video (DVB-S, DVB-S2, NTSC, PAL), VOR, LoRa, M17, Packet (AX.25), Pager (POCSAG), Radiosonde (RS41), Time signal (MSF, DCF77, TDF and WWVB) modems.
  • RTL SDR, Airspy, Airspy HF, LimeSDR, HackRF and SDRplay support via USB OTG as well as networked SDRs
  • 2D and 3D signal analysis in both time and frequency domain with statistical measurements of SNR, THD, THD+N, SINAD, SFDR and channel power
  • Satellite tracker, star tracker, maps and rotator controller

It should work on Android 6 and up. It’s a straight port of the desktop application, so although it will run on a phone, probably best used on a large tablet with a stylus or mouse.

SDRangel on Android
SDRangel on Android

A SDR Digital Voice Hotspot with GNU Radio, MMDVM and QRadioLink

Thank you to Adrian (YO8RZZ) for writing in and sharing with us his article explaining how to use an SDR to set up a digital voice hotspot for digital voice modes supported by MMDVM such as D-Star, DMR, System Fusion, P25 and NXDN. Adrian notes that this is possible with any full duplex SDR such as the LimeSDR or PlutoSDR, or with a combination of simplex devices, such as a HackRF for transmitting combined with an RTL-SDR for receiving.

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.

QRadioLink used as the UI for MMDVM-SDR and GNU Radio

TechMinds: OpenWebRX Feature Overview And Raspberry Pi Setup

Over on YouTube TechMinds has posted his latest video which shows an overview of the features available in OpenWebRX, and also how to set it up on a Raspberry Pi. OpenWebRX is software which allows you to access your SDR remotely via the internet or local network through a web browser. All major SDRs are supported including RTL-SDRs. The software includes a waterfall display, all the standard demodulators, as well as several digital decoders for DMR, YSF, NXDN, D-Star, POCSAG, APRS, FT8, FT4, WSPR, JT65 and JT9.

In the video TechMinds first demonstrates OpenWebRX in action, showing reception of HF SSB amateur radio signals, decoding FT8 and plotting received grids on a map, decoding and plotting APRS on a map and decoding YSF/DSTAR/DMR digital voice. After this demonstration he goes on to show how to set up the OpenWebRX server on a Raspberry Pi via the installation image.

OpenWebRX Feature Overview And Raspberry Pi Setup

Creating a Wireless Pi-Star Nextion Display for Amateur Digital Radio

Thanks to Steve K2GOG of The Hudson Valley Digital Network (HVDN) for submitting his post on how to create a wireless display for Pi-Star. Pi-Star is a pre-built Raspberry Pi image for amateur radio users experimenting with digital voice communications like D-STAR and DMR. They write that it can be used for applications such as a "single mode hotspot running simplex providing you with access to the increasing number of Digital Voice networks, [or a] public duplex multimode repeater".

Pi-Star is compatible with serial based LED displays with built in GUIs like the Nextion. The displays are usually connected directly to the Raspberry Pi, but Steve wanted to use the display remotely. To do this he used a simple and inexpensive 70cm band HC-12 wireless serial port adapter. With the wireless adapters connected to the Pi he was able to see the pulses in SDR# via his RTL-SDR to confirm that the wireless serial signal was being sent. He then connected the second wireless adapter to the Nextion display via a few diodes to drop the voltage, and was able to get the display updating as if it was connected directly.

In the post Steve mentions that HVDN are also giving away an HC-12 and RTL-SDR to the first person to submit some progress with this idea.

Creating a wireless Nextion Display for Pi-Star.
Creating a wireless Nextion Display for Pi-Star.

A Tutorial on using SDRAngel for DMR, D-Star and Fusion Reception with an RTL-SDR

At the end of last month we uploaded a post highlighting the SDRAngel software, which is a general purpose SDR program with some interesting features such as built in digital speech decoders for DMR, D-Star and Fusion. This avoids the need to pipe audio into a separate digital speech decoder program such as DSD+. SDRAngel also has transmit capabilities which makes it useful for SDRs such as the HackRF, PlutoSDR, LimeSDR etc.

Now over on YouTube and his blog K2GOG has uploaded a video tutorial about using SDRAngel. The tutorial starts with installing SDRAngel and explaining that you'll need a 64-bit system and OS to run it. He then goes on to show how to do FM reception and finally how to do digital speech decoding.

DSD+ Version 1.5 Released

Note: This post is now old (written in 2014). As of mid 2015 the latest version of DSD+ can be downloaded from www.dsdplus.com. Also note that in 2015 DSD+ changed their version numbers for some reason, so 1.5 is actually older than 1.1.

Version 1.5 of Digital Speech Decoder Plus (DSD+) has been released. DSD+ is a popular Windows software tool used for decoding digital speech such as P25 with the RTL-SDR. The latest version comes with a simple GUI interface that has an event log that shows call target and source ID history and an audio waveform plot which can help determine if DSD+ is receiving audio correctly. This version of DSD+ has the ability to decode the following protocols.

  • D-STAR
  • NXDN4800
  • NXDN9600
  • DMR/MotoTRBO
  • P25 Phase 1
  • X2-TDMA
  • ProVoice

In addition to the above, the new version comes with an LRRP decoder and display program which should allow you to see on a map the GPS location of broadcasting radios.

DSD+ V1.51 can be downloaded from this link (UPDATE: dead link, use www.dsdplus.com now). The forum thread on RadioReference where the developer releases and discusses the DSD+ software can be found here.

This version of DSD+ comes with all the files needed to make it run already. To use DSD+ V1.5 simply extract the zip file into a folder and double click on DSDPlus.EXE. DSD+ will listen to your default audio device that is set in the Windows sound recording properties. Simply tune to a digital voice signal in SDR# or any other SDR receiver and set the output audio settings accordingly. To start the LRRP display program simply open LRRP.exe.

DSD+ V1.5 LRRP GPS Display
DSD+ V1.5 LRRP GPS Display

Receiving D-STAR Voice with DSD 1.7 on Windows

Recently we posted about PU2VLW’s project where he was able to decode and listen to D-STAR voice using an RTL-SDR and SDR# running on Windows connected via physical audio cable to a second Linux machine running DSD 1.7.

Now a RTL-SDR.com reader by the name of “Skywatcher” has written in to tell us how he was able to compile DSD 1.7 on a Windows PC using Cygwin. This allows him to decode D-STAR audio on a single Windows PC. Skywatcher kindly sent us the steps he used to compile DSD 1.7 on Windows.

1. Download the zip archive for dsd-1.7.0 from here: https://github.com/szechyjs/dsd and then unzip the archive, so that you get the folder dsd-master, which includes all the source files.

2. Download the zip archive for mbelib-1.2.5 from here: https://github.com/szechyjs/mbelib and then unzip the archive, so that you get the folder mbelib-master, which includes all the source files.

3. Download and install the Cygwin environment. It is important to use the 32 bit version. It will not work with the 64 bit version. In the installation process, you also have to make sure that you choose gcc (the compiler) for installation.

4. Within the Cygwin command window, use gcc, to compile every .c file within the folders mbelib-master and dsd-master (subfolders can be ignored), so that you will get an .o file (object file) for each source file.

5. Copy all the resulting .o files from mbelib-master to dsd-master and use gcc again to link all the object files, so that you will get the final executable dsd.exe. This final step also has to include the sndfile library from Cygwin being mentioned in the call of gcc, otherwise it will not work.

6. In order to start dsd.exe, it is necessary to copy cygwin1.dll to the same folder, where your built dsd.exe is. It is very important that the version number of the dll is being lower than 1.7.26, otherwise dsd.exe will crash. If this is not the case for your dll, you have to find an alternative version from the internet. Additionally, it may be necessary to copy more dlls, needed by the sndfile library, next to your dsd.exe. This may depend on your environment variables of your system.

7. For decoding D-Star, you should call DSD like following: dsd -i /dev/dsp -o /dev/dsp -fd

8. For best results, make sure that all your SDR# and VAC sample rates are set to 48kHz and that you have disabled “Filter Audio” in SDR#. Also, the audio volume of SDR# should not be set to high.

With DSD 1.7 running on Windows, Skywatcher was able to get these results shown in the video links below.



EDIT: Reader Kotelnikov007 from the comments section has been kind enough to upload a pre-compiled windows version. https://mega.co.nz/#!Ft9WFbgQ!sOhsUeMC83Xi5Wxjr4eEPoc0WuM0cJOM2bq9DnE4dWE

EDIT 2 (30/12/2016): The above link seems dead. Reader Adrian wrote in to submit his compilation which is available at https://mega.nz/#!jJZRALrb!NylT4jmZIBwCyZqU05EaX8wqObxuaqeTzCD8hHP5gO8.

Adrian also writes

– The list of the required DLLs to make it work are these:
– It is needed to load sndfile library (already prebuilt in Cygwin).
– It needs MBE, but also the ITPP libraries.

Listening to D-STAR Digital Voice with DSD 1.7

D-STAR or (Digital Smart Technologies for Amateur Radio) is a Frequency Division Multiple Access (FDMA) Gaussian Minimum Shift Keying (GMSK) digital voice and data protocol used in amateur radio.

Up until recently it was possible to decode D-STAR headers using either DSD 1.6 or dstar.exe and an RTL-SDR, but it was not possible to decode voice. Now amateur radio hobbyist PU2VLW has brought to our attention that the latest DSD development version 1.7 is capable of decoding D-STAR audio (his post is in Portuguese so we suggest using Google translate). He shows a video of some example D-STAR decoding which we show at the end of this post.

DSD 1.7 can currently be downloaded as source from it’s GitHub respository. Instructions for installing DSD 1.7 on Linux can be found on the post by PU2VLW and the GitHub readme. PU2VLW built DSD 1.7 in Ubuntu 10.04, noting that newer versions of Ubuntu have removed OSS (Open Sound System) support which DSD requires. He then runs SDR# on a Windows PC, tuned to a D-STAR signal, and uses an audio out cable to connect the Windows PC’s audio out to the Ubuntu PC running DSD 1.7.

Update: See this post for installing DSD 1.7 on Windows.

Decodificando Dados e Voz da tecnologia D-STAR sem utilizar DV Dongle

EDIT: There is now a version of DSD+ that can decode D-STAR. https://www.rtl-sdr.com/dsd-version-1-5-released/