How Far Can That Tower See?

Tower & receiver

feet

FCC Antenna Structure Registration Number (ASRN)

Try 1004233. Lookup uses an imported snapshot of FCC ASR registrations.

Enter an ASRN or use the manual inputs below.

Location ZIP or latitude, longitude

A reference label only; no geocoding, terrain, or population lookup is performed.

Base elevation ft AMSL

Registered tower height ft AGL

Radiation center ft AGL

Receiver height ft AGL

AMSL = above mean sea level. AGL = above ground level. Base elevation affects only the AMSL result.

Automatic estimate: tower top minus 8 m (26.2467 ft), with a minimum of 0 ft.

Horizon estimates

Standard radio horizon—k = 4/3 effective Earth

Geometric horizon—k = 1, no refraction

Theoretical area—Circle using the radio-horizon radius

Radiation center AMSL—Enter base elevation to calculate

Estimated populationNot availablePlaceholder — Census data not connected

Population densityNot availablePlaceholder — people per square mile

Formulas & assumptions

Distance from both antenna heights

Heights hₜ and hᵣ are in feet AGL; distances are in miles.

Radio: d ≈ 1.415 × (√hₜ + √hᵣ)
Geometric: d ≈ 1.225 × (√hₜ + √hᵣ)

The calculation uses √(2kRh) for each endpoint, R = 6,371 km, and k = 4/3 for a standard refracting atmosphere or k = 1 for geometric line of sight. Coefficients shown are rounded; calculations use the constants directly. See ITU horizon geometry.

A useful first approximation

Area = πd², a theoretical circle in square miles. Radiation center AMSL = base elevation AMSL + radiation center AGL.

Assumes a smooth Earth and similar ground elevations at both ends. These heights are not HAAT (height above average terrain). Base elevation is not added to the horizon height.

The 8 m antenna setback is a rough convenience estimate, not FCC antenna data. Enter the actual radiation center when known. ZIP or coordinates do not change the results. Population and density are reserved for a future data integration.