{
  "timestamp": "2026-04-01T21:30:00Z",
  "source": "simulation",
  "field_state": "STIR",
  "metrics": {
    "amplitude_rms_dbfs": -42.7,
    "spectral_centroid_hz": 1847,
    "spectral_spread_hz": 312,
    "dominant_frequency_hz": 915,
    "perturbation_count_60s": 23
  },
  "sources_detected": [
    "cellular_band_850mhz",
    "wifi_2.4ghz_b",
    "fm_radio_88-108mhz",
    "power_line_60hz_harmonics"
  ],
  "interpretation": "Urban RF environment, active evening, thunderstorm 40km NW",
  "exists": true
}