A simplified, HF-only software-defined radio (SDR) receiver based on the RX-888 — with improved thermal and RF layout.
The KiCad project lives at the repository root (TAPRX-888.kicad_pro /
.kicad_sch / .kicad_pcb). KiCad 10.0 is the project baseline.
- HF-only — no VHF downconverter
- Larger PCB, 6-layer
- 0603 passive components
- Improved thermal layout
- Improved RF alias filter
- RF shelving filter (bypassable)
- External reference clock input, auto-switching
- Attenuated filter-bypass injector port (used for timesync)
- Support use of a SPI boot EEPROM, with option for USB-only or SPI boot w/ USB fallback
Please see the schematic and layout documents for details.
| Function | Part |
|---|---|
| ADC | LTC2208 (16-bit) |
| Clock generator | Si5351 |
| USB3 controller | EZ-USB FX3 (CYUSB301x) |
| SPI boot flash | MX25L3233F |
The project ships its own mechanical package: a JLCMC split-aluminium enclosure (88 × 38 x 100 mm) with two custom PCB end plates and M3 mounting hardware.
The board's exported STEP is the EE↔ME interface; CI assembles enclosure + board + both plates into a coloured 3D model with a self-contained browser viewer (https://tapr.github.io/TAPRx888/). See mechanical/README.md for the enclosure spec, plate geometry, and fit-check flow.
The KiCad project is at the repo root. Design/PCB, mechanical, and end-plate work
happens on the design branch (one person at a time — KiCad layout files
can't be merged); docs, CI, and tooling go on dev-* branches; flow is
design → dev → main. See CONTRIBUTING.md for how we
collaborate and docs/RELEASE_STRATEGY.md for
branches, CI, and versioning.
CI publishes version-stamped fabrication/design packages as GitHub Releases; the
dev v0.x pre-releases also bundle the end plates, the 3D enclosure assembly,
and a live viewer (https://tapr.github.io/TAPRx888/). Grab the latest from
the Releases page; see
docs/RELEASE_STRATEGY.md for details.
- mechanical/README.md — the enclosure & end-plate package (geometry, fit-check CI, 3D viewer)
- CONTRIBUTING.md — how we collaborate (the two-lane
design/ infra flow, the design baton) - docs/RELEASE_STRATEGY.md — versioning, CI, and how releases are cut
- docs/AI_REVIEW.md — using AI review responsibly; read this before pointing an AI tool at the design
- docs/EMERGENCY_ROLLBACK.md — the parachute: how to turn the CI/branch machinery off if it's ever too much
Device datasheets (LTC2208, Si5351, EZ-USB FX3, MX25L3233F) and RX888 reference material are on the project wiki → Reference Documents.