i saw this FDMA digital signal near a P25 Downlink that cannot be decoded and doesn't sounds like P25 phase 1 / Uplink

Everything runs in your browser - here's what you can do:

• https://web-rtl-433.jasiek.me/ - pick up various devices running on ISM bands (mostly weather stations)
• https://web-rtl-wmbus.jasiek.me/ - read water/gas/electricity meters
• https://web-rtl-multimon.jasiek.me/ - read POCSAG and FLEX pagers

(obvs, only use them when they're legal to use where you are)

When you've got a hammer, everything looks like a nail. Sometimes, though, you get lucky.

I wanted a real-world testbed for CNet, my complex-valued learning framework, and the hypothesis that phase matters for some complex-valued data. Raw 1090 MHz Automatic Dependent Surveillance–Broadcast (ADS-B) waveforms seemed like a good fit.

So I built a prototype that captures aircraft transmissions with a software-defined radio for testing whether the raw I/Q waveforms contain transmitter-specific information beyond the decoded message.

The architecture is edge-first: raw I/Q samples stay local, signal processing and inference run on the edge computer, and only processed events are sent to a dashboard. I also added a controlled experiment that relabels real bursts with another aircraft's address to test whether the monitor detects the inconsistency.

The initial results are promising for checking whether a waveform is consistent with its claimed address, but there are important limitations: performance varies across recording days, and the approach cannot prove physical identity or detect every replay attack.

Demo: https://phasefield.ai/demo.html