SDR Receiver Design
Worked
Created a project doc
Project Specification — Compact P25 SDR Receiver
Status: Draft Compact USB-C receive-only SDR intended to monitor legal, unencrypted P25 Phase 1/Phase 2 public-safety systems using PC/Andro...
I created the project spec and locked the direction to RTL-SDR compatibility for Unitrunker/DSDPlus. Main blocker found: Flux has the RTL2832U, but the matching Rafael tuner and 28.8 MHz clock part are not in the library yet.
Worked for 1 min 48 sec
I’m adding the available RTL-SDR-compatible foundation now: USB-C, RTL2832U, EEPROM, 3.3 V regulator, USB protection, SMA antenna connector, and the key support passives. The missing tuner/clock parts will stay documented as open items rather than using fake placeholders.
Worked
Built the RTL-SDR-compatible schematic foundation for the P25 receiver: USB-C, RTL2832U, EEPROM, AP2112 3.3 V power, USB protection/choke, SMA input, decoupling, and tuner-interface nets. I also created the project spec here: Project Specification. Latest check showed no open ERC warnings/errors, but I have to stop because your account has no available ACUs right now.
Open items:
- Rafael R820T2/R828D/R860 tuner IC is still missing from the Flux library.
- Exact 28.8 MHz RTL2832U clock part is also missing.
- This is not yet a working receiver until those two blocks are added.
Suggested next steps:
- Add/create the missing tuner and 28.8 MHz clock parts.
- Finish the RF front end and tuner wiring.
- Re-run schematic review.
- Move to 4-layer PCB layout with USB differential routing and 50 Ω RF routing.
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