Credits

Credits and License

• QRadioLink is released under an Open Source License, the GNU General Public License version 3.
• The CFreqCtrl and CPlotter widgets are Copyright 2010 Moe Wheatley and Alexandru Csete OZ9AEC.
• The Continuous Envelope SSB transceiver code is used from the gr-cessb GNU radio out of tree module, by Ron Economos W6RZ
• The gr-limesdr GNU radio out of tree module by Lime Microsystems is included and used in qradiolink, with several small modifications to allow for easier DMR burst time synchronization in MMDVM operation mode.
• The M17 digital voice protocol implementation uses code from the OpenRTX project.
• It makes use of other code under compatible licenses, and the authors are credited in the source files.
• Gnuradio is a free software development toolkit that provides signal processing blocks to implement software-defined radios and signal-processing systems.
• Codec2 is developed by David Rowe
• Opus is developed by the Xiph foundation
• Mumble is an open source, low-latency, high quality voice chat software primarily intended for use while gaming. Various third party applications and libraries exist for varying use cases, like web interfaces for server administration, user- and channel-viewers, bots like music bots and more.

Similar to QRadioLink

Free software projects that work on Linux and have similar features to QRadioLink are listed below.

• FreeDV is a Digital Voice mode for HF radio. The application works for Windows, Linux and OSX and allows any SSB radio to be used for low bit rate digital voice. It is the original free software Codec2 implementation. It does not require a SDR and works with any analog radio.
• SvxLink is a great project which inspired the radio linking features of QRadioLink. The Qtel component is a full-featured Echolink GUI client. It does not require using a SDR and can work with any FM radio.
• Gqrx is an open source software defined radio receiver (SDR) powered by the GNU Radio SDK and the Qt graphical toolkit. Gqrx inspired the use of GNU radio in QRadioLink and some features, code and architecture were copied verbatim from Gqrx as the best alternative available. Despite the graphical resemblance to it, Gqrx is much more suitable for the purpose of general SDR receiver. There are several trade-offs made in QRadioLink to emphasize CPU performance to the detriment of signal quality. One such tradeoff is the use of an audio sample rate of 8000 Hz in QRadioLink compared to the more faithful 48000 Hz in Gqrx. Other major differences are lack of Wide FM stereo, RDS decoding, lack of waterfall persistence, lack of I/Q samples recording and lower SSB / AM performance in QRadioLink. Gqrx is also more user friendly and has a wide support community.
• SDRangel is a full SDR transceiver for SSB, FM, DMR, D-Star, C4FM and DVB-S. It can use only SDR hardware but it supports a large number of them.
• Mumble is what QRadioLink uses under the hood. It is a great alternative for people who don't want to use SDR radios.
• Codec2 GMSK is a great and free software alternative to D-Star on VHF-UHF handheld radios. It only requires a radio capable of 9600 baud packet.
• OP25 is a free software implementation of D-Star, DMR and C4FM (Yaesu digital voice standard). It works with FM radios capable of 9600 baud packet as well as SDRs.
• Charon is a stand-alone OFDM transceiver with batman-adv mesh networking capabilities. The IP modem in Charon is very advanced and can be embedded on the PlutoSDR. It is the base for several amateur radio mesh networks. Only works with SDR hardware.
• MMDVM extremely robust free software implementation of D-Star, DMR and C4FM (Yaesu digital voice standard). Works with RaspberryPi, Arduino and any radios capable of 9600 baud packet.
• MMDVM-SDR. Fork of MMDVM for SDR hotspot operation.
• HAMNET Access protocol HAMNET access protocol implementation for SDR devices, initial implementation focused on the ADALM-Pluto device
• M17 digital voice/data open protocol

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