LinHT-hw

Open-source hardware, Linux-based, SDR handheld transceiver. OpenHT successor with greatly simplified hardware - no FPGAs involved. This project offers a replacement board for the Retevis C62 radio, greatly expanding its capabilities.

Hardware

The device uses an MCM-iMX93 System on Module (SoM) running Linux. The RF front-end is based on the Semtech SX1255. The chip is used as a complete IQ modulator/demodulator, allowing for true all-mode support.

Resources

CPU:

Dual-core ARM Cortex-A55 @ 1.7GHz
ARM Cortex-M33 coprocessor @ 250MHz
Floating Point Unit
ARM Ethos U-65 microNPU (Neural Processing Unit with Tensor Flow Lite support)

Memory:

2GB LPDDR4
32GB eMMC

RF:

500kHz bandwidth complete IQ transceiver

Software

Developers can use C/C++/Python as well as (or in conjunction with) GNU Radio flowgraphs. Tools such as gcc are built-in.

Supported modes (so far):

FM transmission and reception with pre-/de-emphasis and CTCSS,
SSB transmission and reception,
M17 - transmission and reception,
TETRA - reception only,
Demo 64QAM transmission at 2Mbps

Other modes can be added later (FreeDV, APRS, etc.).

Images

Download images

Prebuilt images for LinHT can be downloaded here.

Building images

Instructions for setting up the Yocto build environment can be found in the M17 Wiki. All layers required to build the image are located in the M17 Project GitHub:

meta-linht-hardware: Provides machine configuration and hardware support for the LinHT hardware.
meta-linht-software: Provides application software, libraries, and system configuration.
meta-linht-sdr: A modified version of meta-sdr, providing the GNU Radio package.

Flashing

To flash the images to LinHT the Universal Update Utility is needed. LinHT needs to be booted into flash mode (holding the secondary side button while booting). Once in flash mode, the image can be written with uuu: bash uuu -v -b emmc_all imx-boot-mcm-imx93-sd.bin-flash_singleboot linht-image-mcm-imx93.rootfs.wic.zst