Before Friedrichshafen, we want to put the current LinHT development status in one place. We have published many short updates over the last months, and the project moved through several phases: Rev A proof-of-concept testing, Rev B design, manufacturing, first boot, RF tests, audio bring-up, GNSS debugging, and now Rev C planning.
This post summarizes that progress. It starts with what Rev A proved, then goes through what we changed in Rev B, how we built the first boards, what worked during testing, what failed, and what we need to fix before Rev C.
If you want the longer background, start with my older text about the first LinHT prototype: LinHT – Open SDR Handheld for Radio Amateurs. That article describes the Rev A board, the Retevis C62 donor-radio approach, and the basic idea behind LinHT: a Linux-based SDR handheld transceiver, open enough that the radio can be changed in software, not only programmed from a vendor tool.
Rev A was our proof of concept. It showed that the architecture made sense and that the device could work the way we imagined. An i.MX93 system-on-module could boot Linux inside a handheld radio body, run a Yocto image, expose USB networking, talk to the display, run GNU Radio flowgraphs, and use the SX1255 IQ RF front end. We decoded M17, tested TETRA receive, displayed spectrum data on the small screen, and ran enough hardware and software tests to be sure that the concept was valid.
Rev B is the revision where we tried to turn that proof of concept into a much more complete handheld.
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