{
 "generated_utc": "2026-07-28T05:25:02Z",
 "gfs_cycle_utc": "2026-07-28T00:00:00Z",
 "model": {
  "source": "NCEP GFS 0.50 degree",
  "vertical_coordinate": "constant density (isopycnic)",
  "horizon_hours": 168.0,
  "output_interval_min": 30,
  "integration_step_s": 900,
  "wind_field_interval_h": 3
 },
 "staleness": {
  "fresh_seed_max_h": 24.0,
  "served_until_h": 168.0,
  "note": "A trajectory is served for seven days after the last real fix and then the flight disappears. Past dead_reckoned flights the balloon has not been heard from since seed_time, so its present position is a prediction too -- the silent period is reconstructed from GFS analyses of weather that has already happened, which is why wind_source distinguishes analysis from forecast."
 },
 "members": {
  "offsets_m": [
   -2000,
   -1500,
   -1000,
   -500,
   0,
   500,
   1000,
   1500,
   2000
  ],
  "nominal_offset_m": 0,
  "note": "Each member is seeded at the last observed altitude plus its offset and then conserves the density it started with. The ladder is a sensitivity fan, not a probability distribution: adjacent members diverge by roughly 1,200 km over seven days. levels_spanned reports how many GFS levels the fan actually straddles, usually 2 or 3."
 },
 "files": {
  "trajectories_csv_gz": "PBA_forecast_20260728_00Z.csv.gz",
  "trajectories_geojson_gz": "PBA_forecast_20260728_00Z.geojson.gz"
 },
 "counts": {
  "flights": 34,
  "members": 9,
  "rows": 102834
 },
 "flights": [
  {
   "callsign": "AG6NS-23",
   "flight_id": "AG6NS-23_2026-02-07",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 15:38:40",
   "seed_lat": -56.95834,
   "seed_lon": -9.49999,
   "seed_alt_m": 12360.0,
   "seed_age_h": 13.69,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-03 15:15:00",
    "lat": -43.93193,
    "lon": -96.61331,
    "alt_m": 12329.9
   },
   "member_spread_deg": {
    "lat": 39.43,
    "lon": 74.46
   }
  },
  {
   "callsign": "BSS52",
   "flight_id": "BSS52_2025-12-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-24 17:39:48",
   "seed_lat": 59.97917,
   "seed_lon": 4.08333,
   "seed_alt_m": 13000.0,
   "seed_age_h": 83.67,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-07-31 17:15:00",
    "lat": 68.88717,
    "lon": 147.33159,
    "alt_m": 12676.2
   },
   "member_spread_deg": {
    "lat": 16.11,
    "lon": 84.09
   }
  },
  {
   "callsign": "BSS53",
   "flight_id": "BSS53_2026-03-09",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 18:28:18",
   "seed_lat": 44.97917,
   "seed_lon": -27.20833,
   "seed_alt_m": 12980.0,
   "seed_age_h": 10.86,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 18:00:00",
    "lat": 63.24548,
    "lon": 95.80589,
    "alt_m": 12924.6
   },
   "member_spread_deg": {
    "lat": 21.85,
    "lon": 79.43
   }
  },
  {
   "callsign": "BSS54",
   "flight_id": "BSS54_2026-07-09",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 01:06:48",
   "seed_lat": 49.33333,
   "seed_lon": -117.125,
   "seed_alt_m": 14040.0,
   "seed_age_h": 4.22,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 1,
   "nominal_end": {
    "valid_time": "2026-08-04 00:30:00",
    "lat": 29.92292,
    "lon": -42.89123,
    "alt_m": 14511.3
   },
   "member_spread_deg": {
    "lat": 26.38,
    "lon": 178.99
   }
  },
  {
   "callsign": "DG2GG-23",
   "flight_id": "DG2GG-23_2026-05-23",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 02:21:30",
   "seed_lat": 39.95833,
   "seed_lon": -158.58333,
   "seed_alt_m": 12880.0,
   "seed_age_h": 2.98,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-04 01:45:00",
    "lat": 32.82579,
    "lon": -168.22637,
    "alt_m": 13043.2
   },
   "member_spread_deg": {
    "lat": 20.98,
    "lon": 109.2
   }
  },
  {
   "callsign": "DG2GG-25",
   "flight_id": "DG2GG-25_2026-06-15",
   "payload_type": "WSPR",
   "seed_time": "2026-07-25 07:22:00",
   "seed_lat": 68.97917,
   "seed_lon": 68.16667,
   "seed_alt_m": 12990.0,
   "seed_age_h": 69.97,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-01 06:45:00",
    "lat": 73.76199,
    "lon": -117.58316,
    "alt_m": 12783.8
   },
   "member_spread_deg": {
    "lat": 24.27,
    "lon": 79.28
   }
  },
  {
   "callsign": "DG2GG-27",
   "flight_id": "DG2GG-27_2026-07-04",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 08:58:00",
   "seed_lat": 56.29167,
   "seed_lon": 111.625,
   "seed_alt_m": 13140.0,
   "seed_age_h": 20.37,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 08:30:00",
    "lat": 63.56805,
    "lon": -96.80565,
    "alt_m": 12922.2
   },
   "member_spread_deg": {
    "lat": 56.47,
    "lon": 72.09
   }
  },
  {
   "callsign": "DJ2DS-34",
   "flight_id": "DJ2DS-34_2026-04-22",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 23:06:00",
   "seed_lat": 31.04167,
   "seed_lon": -78.54167,
   "seed_alt_m": 13790.0,
   "seed_age_h": 6.23,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 22:30:00",
    "lat": 36.90498,
    "lon": -117.08894,
    "alt_m": 13804.1
   },
   "member_spread_deg": {
    "lat": 25.66,
    "lon": 69.58
   }
  },
  {
   "callsign": "DL0MMZ",
   "flight_id": "DL0MMZ_2026-07-24",
   "payload_type": "OTHER",
   "seed_time": "2026-07-25 15:59:04",
   "seed_lat": 36.60802,
   "seed_lon": 30.46457,
   "seed_alt_m": 8441.0,
   "seed_age_h": 61.35,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 4,
   "nominal_end": {
    "valid_time": "2026-08-01 15:30:00",
    "lat": 61.11031,
    "lon": 134.04813,
    "alt_m": 8620.5
   },
   "member_spread_deg": {
    "lat": 30.96,
    "lon": 48.49
   }
  },
  {
   "callsign": "DL0MZ-493",
   "flight_id": "DL0MZ-493_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-26 16:06:01",
   "seed_lat": 49.625,
   "seed_lon": 25.08333,
   "seed_alt_m": 12400.0,
   "seed_age_h": 37.23,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-02 15:30:00",
    "lat": 57.58993,
    "lon": -165.09556,
    "alt_m": 12228.1
   },
   "member_spread_deg": {
    "lat": 10.44,
    "lon": 346.73
   }
  },
  {
   "callsign": "DL0MZ-493e",
   "flight_id": "DL0MZ-493e_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-26 16:06:02",
   "seed_lat": 49.63134,
   "seed_lon": 25.11007,
   "seed_alt_m": 12400.0,
   "seed_age_h": 37.23,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-02 15:30:00",
    "lat": 62.32413,
    "lon": -169.5406,
    "alt_m": 12005.7
   },
   "member_spread_deg": {
    "lat": 13.24,
    "lon": 347.25
   }
  },
  {
   "callsign": "DN3LEO-13",
   "flight_id": "DN3LEO-13_2026-04-12",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 21:43:00",
   "seed_lat": 67.64583,
   "seed_lon": -42.41667,
   "seed_alt_m": 12380.0,
   "seed_age_h": 7.62,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-03 21:15:00",
    "lat": 64.96586,
    "lon": 78.19898,
    "alt_m": 12485.1
   },
   "member_spread_deg": {
    "lat": 21.23,
    "lon": 256.48
   }
  },
  {
   "callsign": "DO3GU-40",
   "flight_id": "DO3GU-40_2026-06-19",
   "payload_type": "WSPR",
   "seed_time": "2026-07-24 12:15:47",
   "seed_lat": 71.20833,
   "seed_lon": 93.16667,
   "seed_alt_m": 15164.0,
   "seed_age_h": 89.07,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-07-31 11:45:00",
    "lat": 66.58888,
    "lon": 176.72525,
    "alt_m": 14923.4
   },
   "member_spread_deg": {
    "lat": 14.35,
    "lon": 351.47
   }
  },
  {
   "callsign": "EI6BFW-18",
   "flight_id": "EI6BFW-18_2026-07-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 04:53:00",
   "seed_lat": 64.08333,
   "seed_lon": 32.79167,
   "seed_alt_m": 12680.0,
   "seed_age_h": 0.45,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-04 05:00:00",
    "lat": 41.50036,
    "lon": -144.65844,
    "alt_m": 13168.7
   },
   "member_spread_deg": {
    "lat": 33.61,
    "lon": 70.23
   }
  },
  {
   "callsign": "K0PEA-28",
   "flight_id": "K0PEA-28_2026-01-07",
   "payload_type": "WSPR",
   "seed_time": "2026-07-23 12:15:25",
   "seed_lat": 49.85411,
   "seed_lon": 24.91668,
   "seed_alt_m": 13360.0,
   "seed_age_h": 113.08,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-07-30 11:45:00",
    "lat": 57.19494,
    "lon": 78.75661,
    "alt_m": 13641.1
   },
   "member_spread_deg": {
    "lat": 12.68,
    "lon": 324.49
   }
  },
  {
   "callsign": "K5NOT-11",
   "flight_id": "K5NOT-11_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 21:35:37",
   "seed_lat": 33.06244,
   "seed_lon": -74.95833,
   "seed_alt_m": 13300.0,
   "seed_age_h": 7.74,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 21:00:00",
    "lat": 54.39871,
    "lon": 99.86436,
    "alt_m": 12876.8
   },
   "member_spread_deg": {
    "lat": 34.98,
    "lon": 189.36
   }
  },
  {
   "callsign": "K9YO-23",
   "flight_id": "K9YO-23_2026-07-13",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 06:25:49",
   "seed_lat": 52.5833,
   "seed_lon": 125.16663,
   "seed_alt_m": 12840.0,
   "seed_age_h": 22.9,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 06:00:00",
    "lat": 33.70378,
    "lon": 114.4675,
    "alt_m": 13110.7
   },
   "member_spread_deg": {
    "lat": 41.57,
    "lon": 313.65
   }
  },
  {
   "callsign": "KC3LBR-449",
   "flight_id": "KC3LBR-449_2026-07-06",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 03:40:34",
   "seed_lat": 78.66667,
   "seed_lon": 114.66667,
   "seed_alt_m": 13090.0,
   "seed_age_h": 1.66,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-04 03:15:00",
    "lat": 69.92493,
    "lon": -75.99911,
    "alt_m": 13405.8
   },
   "member_spread_deg": {
    "lat": 30.75,
    "lon": 184.73
   }
  },
  {
   "callsign": "KC3LBR-485",
   "flight_id": "KC3LBR-485_2026-03-19",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 10:54:48",
   "seed_lat": 58.91667,
   "seed_lon": -3.41667,
   "seed_alt_m": 12700.0,
   "seed_age_h": 18.42,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 10:30:00",
    "lat": 54.2472,
    "lon": 66.71837,
    "alt_m": 12812.2
   },
   "member_spread_deg": {
    "lat": 18.92,
    "lon": 63.66
   }
  },
  {
   "callsign": "KC5TRB-1",
   "flight_id": "KC5TRB-1_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 19:30:43",
   "seed_lat": 50.16661,
   "seed_lon": -41.4583,
   "seed_alt_m": 13000.0,
   "seed_age_h": 9.82,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 19:00:00",
    "lat": 66.26384,
    "lon": 88.85517,
    "alt_m": 12896.8
   },
   "member_spread_deg": {
    "lat": 26.2,
    "lon": 69.89
   }
  },
  {
   "callsign": "KE8RES-8",
   "flight_id": "KE8RES-8_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 02:18:30",
   "seed_lat": 61.0,
   "seed_lon": -143.20833,
   "seed_alt_m": 12230.0,
   "seed_age_h": 3.03,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-04 01:45:00",
    "lat": 56.07565,
    "lon": -122.84843,
    "alt_m": 12352.6
   },
   "member_spread_deg": {
    "lat": 13.47,
    "lon": 110.83
   }
  },
  {
   "callsign": "KI1TEN-1",
   "flight_id": "KI1TEN-1_2026-07-23",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 22:55:27",
   "seed_lat": 45.60412,
   "seed_lon": -100.49997,
   "seed_alt_m": 12070.0,
   "seed_age_h": 6.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-03 22:30:00",
    "lat": 18.64224,
    "lon": -95.41732,
    "alt_m": 12096.0
   },
   "member_spread_deg": {
    "lat": 19.45,
    "lon": 60.2
   }
  },
  {
   "callsign": "KI6DS-11",
   "flight_id": "KI6DS-11_2026-02-03",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 21:35:45",
   "seed_lat": 58.83328,
   "seed_lon": -50.58331,
   "seed_alt_m": 13660.0,
   "seed_age_h": 7.74,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 21:00:00",
    "lat": 65.4807,
    "lon": 134.37371,
    "alt_m": 13392.1
   },
   "member_spread_deg": {
    "lat": 12.91,
    "lon": 160.21
   }
  },
  {
   "callsign": "N0MPM-31",
   "flight_id": "N0MPM-31_2026-04-16",
   "payload_type": "WSPR",
   "seed_time": "2026-07-21 23:53:19",
   "seed_lat": -24.02088,
   "seed_lon": -135.08331,
   "seed_alt_m": 14600.0,
   "seed_age_h": 149.45,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-07-28 23:30:00",
    "lat": -19.62717,
    "lon": 12.08534,
    "alt_m": 14541.1
   },
   "member_spread_deg": {
    "lat": 32.09,
    "lon": 115.79
   }
  },
  {
   "callsign": "PC4L-11",
   "flight_id": "PC4L-11_2026-07-16",
   "payload_type": "APRS",
   "seed_time": "2026-07-26 12:46:26",
   "seed_lat": 42.93908,
   "seed_lon": 39.39383,
   "seed_alt_m": 11696.0,
   "seed_age_h": 40.56,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-02 12:15:00",
    "lat": 25.83733,
    "lon": 114.92382,
    "alt_m": 12140.7
   },
   "member_spread_deg": {
    "lat": 37.17,
    "lon": 337.95
   }
  },
  {
   "callsign": "SP0LND-6",
   "flight_id": "SP0LND-6_2026-07-25",
   "payload_type": "APRS",
   "seed_time": "2026-07-26 13:19:17",
   "seed_lat": 44.85792,
   "seed_lon": 29.04891,
   "seed_alt_m": 13803.0,
   "seed_age_h": 40.01,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-02 12:45:00",
    "lat": 55.76585,
    "lon": 151.59829,
    "alt_m": 13759.4
   },
   "member_spread_deg": {
    "lat": 19.9,
    "lon": 72.06
   }
  },
  {
   "callsign": "SP2ROC-1",
   "flight_id": "SP2ROC-1_2026-03-14",
   "payload_type": "APRS",
   "seed_time": "2026-07-22 14:00:27",
   "seed_lat": 40.10083,
   "seed_lon": 44.614,
   "seed_alt_m": 14644.0,
   "seed_age_h": 135.33,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-07-29 13:30:00",
    "lat": 23.6597,
    "lon": 72.90388,
    "alt_m": 14884.0
   },
   "member_spread_deg": {
    "lat": 33.29,
    "lon": 50.69
   }
  },
  {
   "callsign": "SP2ROC-41",
   "flight_id": "SP2ROC-41_2026-01-25",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 17:46:00",
   "seed_lat": 50.97917,
   "seed_lon": -22.08333,
   "seed_alt_m": 15660.0,
   "seed_age_h": 11.57,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 17:15:00",
    "lat": 75.07088,
    "lon": 37.86617,
    "alt_m": 15240.4
   },
   "member_spread_deg": {
    "lat": 15.47,
    "lon": 146.33
   }
  },
  {
   "callsign": "SP6MPL-34",
   "flight_id": "SP6MPL-34_2025-12-03",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 04:52:00",
   "seed_lat": 64.39583,
   "seed_lon": 177.08333,
   "seed_alt_m": 13480.0,
   "seed_age_h": 0.47,
   "float_reliable": true,
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   "levels_spanned": 2,
   "nominal_end": {
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    "lon": -122.46629,
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   "member_spread_deg": {
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    "lon": 158.09
   }
  },
  {
   "callsign": "W0DLK-1",
   "flight_id": "W0DLK-1_2026-06-20",
   "payload_type": "WSPR",
   "seed_time": "2026-07-21 06:43:47",
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   "seed_lon": 121.75004,
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   "float_reliable": true,
   "dead_reckoned": true,
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   "nominal_end": {
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   "member_spread_deg": {
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    "lon": 343.84
   }
  },
  {
   "callsign": "W0RBO-12",
   "flight_id": "W0RBO-12_2026-05-02",
   "payload_type": "WSPR",
   "seed_time": "2026-07-28 04:55:23",
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   "seed_lon": 153.04169,
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   "seed_age_h": 0.41,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-04 05:00:00",
    "lat": 25.31325,
    "lon": -98.97015,
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   "member_spread_deg": {
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    "lon": 155.27
   }
  },
  {
   "callsign": "YU9OMT-1",
   "flight_id": "YU9OMT-1_2026-05-24",
   "payload_type": "WSPR",
   "seed_time": "2026-07-26 12:50:00",
   "seed_lat": 39.60417,
   "seed_lon": 35.08336,
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   "seed_age_h": 40.5,
   "float_reliable": true,
   "dead_reckoned": true,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-02 12:15:00",
    "lat": 61.2985,
    "lon": 77.99604,
    "alt_m": 11552.9
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   "member_spread_deg": {
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    "lon": 347.58
   }
  },
  {
   "callsign": "ZS6SRC-37",
   "flight_id": "ZS6SRC-37_2026-07-15",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 14:19:00",
   "seed_lat": -23.25,
   "seed_lon": 17.04167,
   "seed_alt_m": 12190.0,
   "seed_age_h": 15.02,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 3,
   "nominal_end": {
    "valid_time": "2026-08-03 13:45:00",
    "lat": -23.09002,
    "lon": -56.19274,
    "alt_m": 12457.1
   },
   "member_spread_deg": {
    "lat": 16.44,
    "lon": 79.76
   }
  },
  {
   "callsign": "ZS6SRC-84",
   "flight_id": "ZS6SRC-84_2026-07-12",
   "payload_type": "WSPR",
   "seed_time": "2026-07-27 15:20:00",
   "seed_lat": -7.75,
   "seed_lon": 8.375,
   "seed_alt_m": 13090.0,
   "seed_age_h": 14.0,
   "float_reliable": true,
   "dead_reckoned": false,
   "levels_spanned": 2,
   "nominal_end": {
    "valid_time": "2026-08-03 14:45:00",
    "lat": -9.05937,
    "lon": 106.697,
    "alt_m": 13149.1
   },
   "member_spread_deg": {
    "lat": 17.23,
    "lon": 267.83
   }
  }
 ]
}