{
  "schema": "https://pointcast.xyz/schemas/radius-90245-v1.json",
  "name": "RADIUS / 90245",
  "canonical": "https://pointcast.xyz/ues/radius",
  "description": "An interactive free-space RF link bench centered on El Segundo and bounded to the University of El Segundo 25-mile field layer.",
  "center": {
    "name": "El Segundo, California",
    "postalCode": "90245",
    "latitude": 33.9192,
    "longitude": -118.4165,
    "maximumMiles": 25
  },
  "presets": [
    {
      "id": "field-sensor",
      "label": "Field sensor",
      "kicker": "915 MHz · narrowband",
      "note": "A low-rate sensor thought experiment across the local field layer.",
      "distanceMiles": 8,
      "frequencyGHz": 0.915,
      "transmitPowerDbm": 20,
      "combinedGainDbi": 6,
      "bandwidthMHz": 0.2,
      "noiseFigureDb": 6,
      "extraLossDb": 9
    },
    {
      "id": "rooftop-mesh",
      "label": "Rooftop mesh",
      "kicker": "5.8 GHz · 20 MHz",
      "note": "A line-of-sight rooftop model with directional gain and an obstruction allowance.",
      "distanceMiles": 4.5,
      "frequencyGHz": 5.8,
      "transmitPowerDbm": 26,
      "combinedGainDbi": 28,
      "bandwidthMHz": 20,
      "noiseFigureDb": 6,
      "extraLossDb": 12
    },
    {
      "id": "satcom-thought",
      "label": "Satcom thought experiment",
      "kicker": "26 GHz · 50 MHz",
      "note": "A free-space Ka-range exercise. Rain, oxygen, pointing error, and regulation are deliberately outside this model.",
      "distanceMiles": 25,
      "frequencyGHz": 26,
      "transmitPowerDbm": 35,
      "combinedGainDbi": 44,
      "bandwidthMHz": 50,
      "noiseFigureDb": 7,
      "extraLossDb": 18
    }
  ],
  "sources": [
    {
      "id": "itu-p525",
      "title": "ITU-R P.525-5 · Calculation of free-space attenuation",
      "url": "https://www.itu.int/rec/R-REC-P.525-5-202411-I/en",
      "use": "Free-space basic transmission loss."
    },
    {
      "id": "nist-c",
      "title": "NIST · Definitions of SI base units",
      "url": "https://www.nist.gov/si-redefinition/definitions-si-base-units",
      "use": "Exact speed of light in vacuum: 299,792,458 m/s."
    },
    {
      "id": "ssc-command-plan",
      "title": "Space Systems Command · Command Plan",
      "url": "https://www.ssc.spaceforce.mil/Portals/3/Documents/SSC_Command_Plan_2024_Final_04_02_2025_.pdf",
      "use": "Local context: Space Systems Command is headquartered in El Segundo."
    }
  ],
  "formulas": {
    "freeSpacePathLoss": "92.45 + 20 log10(distance km) + 20 log10(frequency GHz)",
    "receivedPower": "transmit power + combined antenna gain - extra loss - free-space path loss",
    "noiseFloor": "-174 + 10 log10(bandwidth Hz) + noise figure",
    "shannonCapacity": "bandwidth × log2(1 + linear SNR)",
    "midpointFresnelRadius": "sqrt(wavelength × distance / 4)",
    "propagationDelay": "distance / 299792458 m/s"
  },
  "boundary": "Educational free-space reference only. It is not a site survey, spectrum authorization, safety analysis, or deployment recommendation.",
  "generatedAt": "2026-07-19T16:25:24.014Z",
  "human": "https://pointcast.xyz/ues/radius",
  "examples": [
    {
      "id": "field-sensor",
      "input": {
        "id": "field-sensor",
        "label": "Field sensor",
        "kicker": "915 MHz · narrowband",
        "note": "A low-rate sensor thought experiment across the local field layer.",
        "distanceMiles": 8,
        "frequencyGHz": 0.915,
        "transmitPowerDbm": 20,
        "combinedGainDbi": 6,
        "bandwidthMHz": 0.2,
        "noiseFigureDb": 6,
        "extraLossDb": 9
      },
      "result": {
        "distanceMiles": 8,
        "frequencyGHz": 0.915,
        "transmitPowerDbm": 20,
        "combinedGainDbi": 6,
        "bandwidthMHz": 0.2,
        "noiseFigureDb": 6,
        "extraLossDb": 9,
        "distanceKm": 12.874752,
        "wavelengthMeters": 0.32764203060109287,
        "freeSpacePathLossDb": 113.87319932519534,
        "receivedPowerDbm": -96.87319932519534,
        "noiseFloorDbm": -114.98970004336019,
        "snrDb": 18.116500718164843,
        "shannonCapacityMbps": 1.2080522506247056,
        "propagationDelayMicroseconds": 42.94555001780599,
        "firstFresnelRadiusMeters": 32.4742586088023,
        "linkState": "workable"
      }
    },
    {
      "id": "rooftop-mesh",
      "input": {
        "id": "rooftop-mesh",
        "label": "Rooftop mesh",
        "kicker": "5.8 GHz · 20 MHz",
        "note": "A line-of-sight rooftop model with directional gain and an obstruction allowance.",
        "distanceMiles": 4.5,
        "frequencyGHz": 5.8,
        "transmitPowerDbm": 26,
        "combinedGainDbi": 28,
        "bandwidthMHz": 20,
        "noiseFigureDb": 6,
        "extraLossDb": 12
      },
      "result": {
        "distanceMiles": 4.5,
        "frequencyGHz": 5.8,
        "transmitPowerDbm": 26,
        "combinedGainDbi": 28,
        "bandwidthMHz": 20,
        "noiseFigureDb": 6,
        "extraLossDb": 12,
        "distanceKm": 7.2420480000000005,
        "wavelengthMeters": 0.05168835482758621,
        "freeSpacePathLossDb": 124.91578785079312,
        "receivedPowerDbm": -82.91578785079312,
        "noiseFloorDbm": -94.98970004336019,
        "snrDb": 12.073912192567064,
        "shannonCapacityMbps": 81.95385381057176,
        "propagationDelayMicroseconds": 24.15687188501587,
        "firstFresnelRadiusMeters": 9.673798978457365,
        "linkState": "workable"
      }
    },
    {
      "id": "satcom-thought",
      "input": {
        "id": "satcom-thought",
        "label": "Satcom thought experiment",
        "kicker": "26 GHz · 50 MHz",
        "note": "A free-space Ka-range exercise. Rain, oxygen, pointing error, and regulation are deliberately outside this model.",
        "distanceMiles": 25,
        "frequencyGHz": 26,
        "transmitPowerDbm": 35,
        "combinedGainDbi": 44,
        "bandwidthMHz": 50,
        "noiseFigureDb": 7,
        "extraLossDb": 18
      },
      "result": {
        "distanceMiles": 25,
        "frequencyGHz": 26,
        "transmitPowerDbm": 35,
        "combinedGainDbi": 44,
        "bandwidthMHz": 50,
        "noiseFigureDb": 7,
        "extraLossDb": 18,
        "distanceKm": 40.233599999999996,
        "wavelengthMeters": 0.011530479153846154,
        "freeSpacePathLossDb": 152.8412448368846,
        "receivedPowerDbm": -91.84124483688461,
        "noiseFloorDbm": -90.01029995663981,
        "snrDb": -1.8309448802448003,
        "shannonCapacityMbps": 36.38524369344645,
        "propagationDelayMicroseconds": 134.2048438056437,
        "firstFresnelRadiusMeters": 10.76931620489649,
        "linkState": "below-noise"
      }
    }
  ]
}