FCC Data Dictionary¶

Data dictionary for the geo team covering FCC station data and coverage contour polygons.

Data Sources¶

1. Station Database (DuckDB)¶

Property	Value
Location	`./db/cbradio.db`
Format	DuckDB database
Table	`station`
Records	1,908 stations
FCC Coverage	1,563 stations (81.9%)

2. Coverage Contour Files¶

Property	Value
Location	`./fcc/data/contours/`
Format	GeoJSON (RFC 7946)
Naming	`{CALLSIGN}.json` (e.g., `WBCH_AM.json`)
Projection	WGS84 (EPSG:4326)
Geometry	Polygon (closed ring, 361 points)

Database Schema¶

Station Table - FCC Columns¶

Column	Type	Description	Example
`fcc_facility_id`	VARCHAR	Unique FCC facility identifier	`"55492"`
`fcc_frequency`	DECIMAL(10,3)	Frequency in kHz (AM) or MHz (FM)	`1230.000`
`fcc_power_kw`	DECIMAL(10,3)	Transmit power in kilowatts	`1.000`
`fcc_antenna_lat`	DECIMAL(10,6)	Antenna latitude (WGS84)	`35.163611`
`fcc_antenna_lon`	DECIMAL(10,6)	Antenna longitude (WGS84)	`-114.070000`
`fcc_antenna_height_m`	DECIMAL(10,2)	Antenna height above mean sea level (meters)	`429.00`
`fcc_station_class`	VARCHAR	FCC station classification	`"C"`
`fcc_hours_operation`	VARCHAR	Hours of operation code	`"D"`
`fcc_ant_mode`	VARCHAR	Antenna mode	`"ND1"`
`fcc_tower_count`	INTEGER	Number of antenna towers	`1`
`fcc_service_contour`	VARCHAR	Contour filename (if available)	`"WBCH_AM.json"`
`fcc_last_synced`	TIMESTAMP	Last FCC sync timestamp	`2024-12-24 19:29:00`

Station Table - Other Useful Columns¶

Column	Type	Description
`id`	VARCHAR	Internal UUID primary key
`callsign`	VARCHAR	Station callsign (e.g., `WBCH-AM`)
`state`	VARCHAR	Two-letter state code
`nielsen_dma`	VARCHAR	Nielsen DMA market name
`owner`	VARCHAR	Station owner/licensee

Enumerated Values¶

Station Class (`fcc_station_class`)¶

Class	Description	Typical Power
`A`	Clear channel (AM)	10-50 kW
`B`	Regional (AM/FM)	5-50 kW
`C`	Local (AM) / High-power (FM)	0.25-100 kW
`C0`	FM subclass	100 kW
`C1`	FM subclass	100 kW
`C2`	FM subclass	50 kW
`C3`	FM subclass	25 kW
`D`	Daytime only (AM) / Low-power (FM)	0.25-10 kW

Hours of Operation (`fcc_hours_operation`)¶

Code	Description
`U`	Unlimited (24/7)
`D`	Daytime only
`N`	Nighttime only

Antenna Mode (`fcc_ant_mode`)¶

Code	Description
`ND`	Non-directional
`ND1`	Non-directional (single pattern)
`DA`	Directional antenna
`DA1`	Directional (single pattern)
`DA2`	Directional (day/night patterns)
`DA-N`	Directional nighttime
`DA-D`	Directional daytime

GeoJSON Contour Schema¶

File Structure¶

{
  "type": "Feature",
  "properties": {
    "callsign": "WBCH",
    "facility_id": 3990,
    "service_type": "am",
    "frequency": 1220.0,
    "power_kw": 0.25,
    "station_class": null,
    "antenna_lat": 42.626111,
    "antenna_lon": -85.278056
  },
  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [-85.278056, 43.031705],
        [-85.268372, 43.031643],
        ...
        [-85.278056, 43.031705]
      ]
    ]
  }
}

Properties¶

Property	Type	Description
`callsign`	string	Station callsign (without -AM/-FM suffix)
`facility_id`	integer	FCC facility identifier
`service_type`	string	`"am"` or `"fm"`
`frequency`	number	Frequency in kHz (AM) or MHz (FM)
`power_kw`	number	Transmit power in kilowatts
`station_class`	string\|null	FCC station class
`antenna_lat`	number	Antenna latitude
`antenna_lon`	number	Antenna longitude

Geometry¶

Type: Polygon
Coordinates: Array of [longitude, latitude] pairs (GeoJSON order)
Points: 361 (360° coverage at 1° intervals, plus closing point)
Ring: Closed (first point = last point)
CRS: WGS84 (EPSG:4326)

Sample Queries¶

Get all stations with coordinates¶

SELECT
    callsign,
    fcc_facility_id,
    fcc_antenna_lat AS lat,
    fcc_antenna_lon AS lon,
    fcc_power_kw AS power,
    fcc_station_class AS class
FROM station
WHERE fcc_antenna_lat IS NOT NULL
ORDER BY fcc_power_kw DESC;

Get stations with contour files¶

SELECT
    callsign,
    fcc_service_contour AS contour_file,
    fcc_power_kw,
    state
FROM station
WHERE fcc_service_contour IS NOT NULL;

Export as GeoJSON points¶

SELECT json_object(
    'type', 'Feature',
    'properties', json_object(
        'callsign', callsign,
        'facility_id', fcc_facility_id,
        'power_kw', fcc_power_kw,
        'class', fcc_station_class
    ),
    'geometry', json_object(
        'type', 'Point',
        'coordinates', json_array(fcc_antenna_lon, fcc_antenna_lat)
    )
)
FROM station
WHERE fcc_antenna_lat IS NOT NULL;

Data Statistics¶

Metric	Value
Total stations	1,908
Stations with FCC data	1,563 (81.9%)
Station classes	9 distinct values
Power range	0.065 - 100 kW
Average power	11.59 kW
Contour file size	~23 KB each

Generating Contour Files¶

To regenerate all contour GeoJSON files:

cd /home/bisenbek/projects/nominate/cbradio
source ~/.pyenv/versions/nominates/bin/activate
python -m fcc.sync --all --force

Note: This takes ~30 minutes due to FCC API rate limiting (1 req/sec).

API Source¶

All FCC data is sourced from:

FCC Contours API https://geo.fcc.gov/api/contours/entity.json

Parameters: - callsign - Station callsign (e.g., WBCH) - serviceType - am or fm

Contact¶

For questions about this data, contact the data engineering team.

Last updated: December 2024