Identifying a nearby tower from public records

Goal

Replace assumptions about a nearby structure with its registered parameters, which change any exposure estimate by orders of magnitude.

Equipment

• Broadband RF power-density meter
• Directional antenna (log-periodic or horn)

Procedure

1. Search the FCC Antenna Structure Registration database by location to find registered structures and their coordinates and heights.
2. Cross-reference the licence records for the structure to identify licensees, services and authorised parameters.
3. Compute the geometry: horizontal distance, height difference, and the elevation angle from the dwelling to the antenna.
4. Compare that angle with typical sector downtilt to judge whether the dwelling is in the main beam, a sidelobe, or below the pattern.
5. Measure indoors and outdoors with a directional antenna to confirm the bearing matches the structure before attributing any reading to it.

Pitfalls

• Assuming the closest structure is the dominant source; a farther tower on boresight often is
• Ignoring that structures below the registration height threshold, and many rooftop and small-cell installations, do not appear in ASR at all
• Estimating from EIRP alone without antenna pattern, which overstates ground-level exposure at the tower base substantially

Interpret results against

• FCC general population MPE, 300–1500 MHz
• Swiss installation limit value for mobile phone antennas

Related records

• Macro cell tower (LTE / 5G sector antenna)

  Sector antennas radiate on the order of 1000 W EIRP per sector on the main beam, which is aimed above and away from the tower base — ground-level exposure directly beneath a tower is usually lower than at a few hundred metres away.

  Sources & emitters

• How far should you live from a cell tower?

  No authority defines a setback distance; beam geometry dominates, and measured residential levels are hundreds of times below limits. Look up the structure and measure.

  Direct answers

Sources

1. fcc-asr Antenna Structure Registration (ASR) public access database downloads — Federal Communications Commission. government, link checked 2026-08-12.
2. fcc-oet65 OET Bulletin 65: Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields — Federal Communications Commission, Office of Engineering and Technology, 1997. government, link checked 2026-08-12.