M17 Project

News feed

  • LinHT Rev B – GNSS antenna issues

    Vlastimil OK5VAS recently tested the GNSS module. Unfortunately, the module used (Quectel LG77L) does not obtain a fix, even when enabled for 30 minutes, outdoors.

    The most suspicious part, and likely culprit, is the path between the antenna and the module:

    GNSS module (lower left-hand side, 7x7mm rectangle with pads) and the antenna (top, center) with a copper keep-out zone.

    When measured, S11 (from the GNSS module’s perspective) looks like this:

    S11 plots for setups with cover (chassis) removed and held in place. Note the approx. 200 MHz difference between L1 frequency and where the dip actually is.

    A quick ad hoc fix before Friedrichshafen ham fair is to place an additional capacitor along the coplanar waveguide:

    Proposed fix using a 0.75pF series capacitor.

    Some more experimentation is required. Keep your fingers crossed! See you in Germany!

  • mvoice 1.4.2 now available

    News from Tom, N7TAE:

    Version 1.4.2 of mvoice is now available. It pulls the https://m17-project.github.io/hostfiles/M17Hosts.json file to initialize the reflector selection drop-down menu. A GIANT Thank You to Jim N1ADJ for setting this up!

    More details: https://github.com/n7tae/mvoice

  • Getting on the air with the MSEVEN iOS app

    Video by Jeff Scoville, AE5ME.

  • LinHT Rev B – hardware testing status

    It took us some time, but here’s a quick update on where we’re at with the LinHT Rev B hardware tests:

    What‘s working?

    • Variable RF input attenuators
    • RF switch – switching between TX/RX paths
    • RF PA (Power Amplifier) – functional, delivering about 4.5 watts (CW)
    • GNSS connection – UART interface (NMEA)

    Still requires testing

    • GNSS receiver’s antenna path
    • PMU (Power Management Unit) – battery voltage measurements

    Known problems

    • Audio codec IC – reset and I²C communication issues needing a bit of investigation
    • The button below PTT not triggering USB boot sequence correctly
    (more…)

  • OpenRTX v0.4.4 release

    New, M17-related functions include:

    • metadata text transmission and reception
    • packet transmission and reception
    • microphone noise reduction through ADC oversampling (results in a perceptibly better Codec2 behavior)

    More info: https://github.com/OpenRTX/OpenRTX/releases/tag/v0.4.4

  • LinHT rev B – first boot

    Sharing great news from Andreas OE3ANC. Good work, team!

  • m17-gateway now supports three hardware platforms including SX1255 HAT

    I’m happy to announce release 0.5.0 of my M17 Go tools project at github.com/jancona/m17 with some significant updates!

    Three hardware platforms, full M17 feature support

    m17-gateway now supports three different modem/hardware platforms:

    • CC1200 Pi HAT — the original supported hardware
    • SX1255 Pi HAT — newly supported this month
    • MMDVM-compatible hotspots and modems — for those who already have MMDVM hardware

    All three give you the full M17 feature set, including voice, SMS messaging, and GNSS-based station position mapping — features that many other M17 hotspot platforms don’t support.

    Both the SX1255 and MMDVM platforms support full duplex operation, which means they can be used as full M17 repeaters — not just hotspots. If you’ve been thinking about putting up an M17 repeater, this is a viable path.

    Getting started

    The easiest way to get a working hotspot is DK1MI’s installer script, which sets up m17-gateway along with a web dashboard. If you just want the gateway itself, pre-built .deb packages for arm64 are on the releases page, or you can build it yourself from the instructions in the README.

    Also in the project: an experimental messaging bridge

    There’s also a new and very experimental tool called m17-bridge that connects M17 SMS traffic to Discord, IRC, and APRS. It’s not ready for production use yet, but in the next month or two I plan to stand up a public example node so folks can experiment with it. Stay tuned!

    Latest release is v0.5.1. Full source, docs, and binaries at: https://github.com/jancona/m17

  • LinHT Rev B update

    We finally have the first fully assembled LinHT Rev B PCB.

    The board powers up correctly, the ATTiny power-management firmware is working, and the PMU logic now controls the startup/shutdown sequence as intended.

    USB-C charging is also working as expected, and the whole device can be powered on with the rotary ON/OFF switch.

    We also confirmed debug UART from the SoM is available on the Kenwood connector and works with common Baofeng-style USB serial adapters.

    There is still a lot of work ahead: update the Linux device tree for the new Rev B pinout, validate all new peripherals, and fully test GNSS, the RF power amplifier stage, and the rest of the hardware.

    Stay tuned.

  • LinHT boards have arrived!

    Today, we have received a set of three Rev B boards. They will be tested in the coming days. Stay tuned!

    What’s new in Rev B:
    – redesigned power supply
    – internal RF power amplifier (~5W at 435MHz, CW)
    – improved RF receiver path (added variable attenuation)
    – GNSS receiver
    – battery charging through USB-C
    – cleaner layout and grounding

    Photo courtesy of Vlastimil, OK5VAS.

  • LinHT – Yocto image update

    News from Andreas OE3ANC:

    I just uploaded a new image for Rev A

    • Latest versions of LinHT repos
    • Removed gr-bokeh (this removes nodejs dependencies which makes build faster)
    • Updated raylib (new lic hash)
    • Changed default sample rate to 125k
    • Creating /var/lib/linht folder for gui_test sqlite

    The new image can be downloaded here: https://m17project.org/linht/experimental/

    Flashing instructions: https://wiki.m17foundation.org/index.php?title=LinHT

    This is how the display looks like now:

    LinHT Rev A running gui_test in M17 mode.

    Rev B is still in the works. Stay tuned for more updates.