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      "sources",
      "tests"
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    "When u_* are set, first-order GUM sensitivity with independent inputs (no ρ on this page)"
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  "limitations": [
    "Ideal free space only",
    "Extends electrical.rf.fspl",
    "Optional u_* use GUM sensitivity on Pr only (no MC/ρ/νeff UI); empty u_* preserves 1.0.0 fields"
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  "boundary_conditions": [
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    "L_dB < 0 → VALUE_MUST_BE_NON_NEGATIVE",
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      "section": "Free-space link",
      "supports": "FSPL and received-power form",
      "kind": "reference"
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    {
      "title": "ITU-R P.525",
      "section": "Free-space attenuation",
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        "d_m": 1000,
        "f_Hz": 2400000000,
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        "Pt_dBm": 20,
        "Gt_dBi": 0,
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        "d_m": 1000,
        "f_Hz": 2400000000,
        "Gt_dBi": 6,
        "Gr_dBi": 6,
        "S_dBm": -90
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        "Pt_dBm": 20,
        "Gt_dBi": 6,
        "Gr_dBi": 6,
        "L_dB": 0,
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    {
      "id": "missing-Pt",
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        "d_m": 1000,
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        "Gt_dBi": 0,
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        "u_d_m": 50
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        "Pt_dBm": 20,
        "Gt_dBi": 0,
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        "uncertainty": {
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          "u_c": 0.6622776585478435,
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          "largest": {
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      "id": "property-pr",
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