Non-Commercial Amateur Radio Digital Voice Projects and Technology

Annotated MLA-style entries with live links (URL shown as link text). Accessed 27 Dec. 2025.

Works Cited (Annotated)

  1. drowe67. “codec2.” GitHub, n.d., https://github.com/drowe67/codec2. Accessed 27 Dec. 2025.
    Primary source repository for Codec 2, a low-bitrate open speech codec widely used in ham digital-voice experimentation (notably FreeDV and M17 ecosystems).
  2. DVSwitch. “The DVSwitch Analog_Reflector and DVSwitch HTML Client (hUC).” DVSwitch, n.d., https://dvswitch.org/Analog%20Reflector/Analog_Reflector.html. Accessed 27 Dec. 2025.
    Documentation for DVSwitch’s web-accessible client/reflector components, used to bridge and operate multi-mode digital-voice systems (e.g., via Analog_Bridge, MMDVM_Bridge, and related tooling).
  3. DVSwitch. “Wiki.” DVSwitch Groups.io, n.d., https://dvswitch.groups.io/g/main/wiki. Accessed 27 Dec. 2025.
    Community documentation hub for provisioning and operating DVSwitch-based digital voice networks and bridges.
  4. FreeDV. “FreeDV | Open Source HF Digital Voice for Amateur Radio.” FreeDV, n.d., https://freedv.org/. Accessed 27 Dec. 2025.
    Project site for FreeDV, an open-source suite of HF digital voice modes (including RADE) plus downloads, getting-started guides, and technical references.
  5. g4klx. “DStarRepeater.” GitHub, n.d., https://github.com/g4klx/DStarRepeater. Accessed 27 Dec. 2025.
    Homebrew D-STAR repeater controller software that integrates with ircDDBGateway and supports a variety of modem and controller configurations.
  6. g4klx. “ircDDBGateway.” GitHub, n.d., https://github.com/g4klx/ircDDBGateway. Accessed 27 Dec. 2025.
    D-STAR gateway software enabling callsign routing via ircDDB and interoperability with major reflector types; includes policy controls, announcements, and remote-control facilities.
  7. g4klx. “MMDVM.” GitHub, n.d., https://github.com/g4klx/MMDVM. Accessed 27 Dec. 2025.
    Firmware for the Multi-Mode Digital Voice Modem (MMDVM), a foundational open platform that underpins many amateur digital-voice hotspot and repeater builds.
  8. g4klx. “MMDVMHost.” GitHub, n.d., https://github.com/g4klx/MMDVMHost. Accessed 27 Dec. 2025.
    Host software for running MMDVM-based hotspots/repeaters and networking components across multiple digital-voice modes (DMR, D-STAR, YSF, P25, NXDN, etc.).
  9. g4klx. “YSFClients.” GitHub, n.d., https://github.com/g4klx/YSFClients. Accessed 27 Dec. 2025.
    System Fusion (YSF) networking clients (gateway and parrot) that complement MMDVMHost; used with YSF reflectors and Wires-X style control workflows.
  10. HBLink-org. “HBLink.org.” HBLink.org, n.d., https://hblink-org.github.io/. Accessed 27 Dec. 2025.
    Documentation portal for HBLink (Homebrew repeater protocol networking tools) commonly used to build and extend DMR networking/bridging on top of MMDVM ecosystems.
  11. juribeparada. “MMDVM_HS.” GitHub, n.d., https://github.com/juribeparada/MMDVM_HS. Accessed 27 Dec. 2025.
    Hotspot-focused firmware fork supporting multiple digital-voice modes; used by popular personal hotspot boards derived from MMDVM architectures.
  12. M17 Project. “M17 Project – Bringing good stuff since 2019.” M17 Project, 25 Dec. 2025, https://m17project.org/. Accessed 27 Dec. 2025.
    Community-run effort developing the open M17 digital voice/data protocol plus supporting software, hardware, and implementation notes.
  13. M17-Project. “libm17.” GitHub, n.d., https://github.com/M17-Project/libm17. Accessed 27 Dec. 2025.
    Reference C library implementing major parts of the M17 RF/protocol stack for use in modems, firmware, and tooling.
  14. M17-Project. “M17_spec.” GitHub, n.d., https://github.com/M17-Project/M17_spec. Accessed 27 Dec. 2025.
    Living specification repository for the M17 protocol, useful for implementers building encoders/decoders, modems, or interoperability tests.
  15. nostar. “DroidStar.” GitHub, n.d., https://github.com/nostar/DroidStar. Accessed 27 Dec. 2025.
    Cross-platform digital-voice client application for connecting to reflectors/servers across multiple modes (e.g., D-STAR, DMR, YSF/Fusion, M17).
  16. open-ham. “OpenGD77.” GitHub, n.d., https://github.com/open-ham/OpenGD77. Accessed 27 Dec. 2025.
    Open-source firmware for several popular DMR handhelds, adding features and experimentation pathways beyond stock firmware.
  17. OpenRTX. “OpenRTX.” OpenRTX, n.d., https://openrtx.org/. Accessed 27 Dec. 2025.
    Open-source firmware project for certain digital ham radios; includes experimental support for M17 on supported platforms.
  18. Pi-Star. “Home.” Pi-Star, 18 Jan. 2019, https://www.pistar.uk/. Accessed 27 Dec. 2025.
    Pre-configured Raspberry Pi image and dashboard that simplifies setup and operation of amateur digital-voice hotspots and repeaters using common open-source backends.
  19. Rowetel. “Codec 2.” Rowetel, n.d., https://www.rowetel.com/wordpress/?page_id=452. Accessed 27 Dec. 2025.
    Overview, samples, and technical context for Codec 2, including related modem work and links to source code and documentation resources.