work / 2026
Pocket RF Signal Surveyor
A handheld board that sweeps the sub-GHz bands and logs anything it hears. PortaPack-adjacent, built from parts that cost less than dinner.
The problem
Walking a site with a laptop, an SDR dongle, and a tangle of cables is a great way to look suspicious and a bad way to take consistent readings. I wanted a pocketable instrument: sweep, log, and geotag common ISM bands, all day, on one charge.
Constraints
- Budget: under $80 in parts — this had to be reproducible by other hobbyists
- Battery: a full working day of periodic sweeps
- Legality: receive-only, always; the firmware physically can't transmit
The build
An ESP32-S3 drives a CC1101 transceiver (locked to receive) and a small LCD, with everything logged to SD as CSV. The enclosure is a two-piece printed shell with a lanyard loop — designed with the same workflow documented in Budget PCB workflow.
| Spec | Result |
|---|---|
| Parts cost | $61 at qty 1 |
| Battery life | ~11 h at one sweep/min |
| Bands | 315 / 433 / 868 / 915 MHz |
What went wrong
Rev A had the LDO footprint incident — full postmortem in the Bench failure log. Rev B came up first try.
What shipped
A working surveyor, the KiCad sources, and firmware. The point wasn't a product — it was proof that useful RF instrumentation fits inside a hobby budget when scope stays honest.