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.
Tech YouTuber Lon.TV has recently uploaded a video demonstrating how to identify and decode various digital transmissions with an RTL-SDR dongle. In the video he explains how to use VB Cable to pipe audio from SDR# into various decoders, and then goes on to show DMR, APRS, POCSAG, L-Band AERO, FT8, and JS8/JS8CALL all being decoded via an RTL-SDR Blog V3 dongle.
Software Defined Radio Part 2 - Decoding Digital Transmissions with an RTL-SDR USB Radio
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.
In his latest episode of his SDR Guide series Rob from Frugal Radio provides a walkthrough on using DSDPlus Fastlane to decode trunked P25 with just one RTL-SDR V3 dongle. In the video he explains each of the various DSDPlus windows, and demonstrates decoding of a Simulcast system in his area.
DSDPlus is a program capable of decoding various digital audio protocols such as DMR and P25. The "Fastlane" version is a $25 paid upgrade which allows you to download the latest version that contains more features.
2021 SDR Guide Episode 9 : $25 DSDPlus P25 LSM trunking walkthrough using 1 x $25 RTL-SDRv3
In this weeks episode of Frugal Radio's SDR Guide videos Rob shows how a FM bandstop filter can help in certain situations. A FM bandstop is designed to reduce the power level of FM broadcast stations that are received by your antenna. FM broadcast stations are often extremely strong, and this can cause an SDR to overload, resulting in poor reception on other frequencies.
In the video he demonstrates how he is unable to receive air traffic control signals due to FM broadcast overload. After inserting an FM bandstop filter the air traffic signals become receivable. We note that we sell a low cost FM bandstop filter in our store.
2020 SDR Guide EP8 : Overcoming FM Broadcast Interference with a Nooelec flamingo band stop filter
In a second video Rob demonstrates the use of the recently released Simple DMR plugin which we posted about earlier.
Quickest way to monitor DMR with your SDR? Simple DMR for SDR# installed in under 5 mins!
At the beginning of 2020 Annunaki (@StupotSinders) released his third party user interface for DSDPlus. DSDPlus is a digital speech decoder capable of decoding protocols such as P25 P1, DMR, NXDN and more with an SDR such as the RTL-SDR. As it is a command line tool, it can be a little daunting for some users, which is where the GUI comes in handy.
Recently Annunaki has released an SDR# plugin version of DSDPlusUI. This makes it so you can visualize the digital voice signals at the same time as controlling and decoding with DSDPlus. The plugin is available on the DSDPlusUI website at dsdplusui.com. To use it you will need to be using SDR# 1777 or later.
Simple DMR decoder. No external dependencies, no settings, uses SDR # audio path. Designed for listening to unencrypted DMR channels. The voice from both slots is mixed into one channel.
To install the plugin simply copy the dll's from the zip file into the SDR# folder, then copy the line from the magline.txt text file into the plugins.xml file which can be opened with any text editor.