---
kind: "section"
citation: "47 C.F.R. § 73.311"
title: "47"
number: "73.311"
heading: "Field strength contours."
url: "https://uscodex.org/cfr/47/73.311"
---

# §73.311. Field strength contours.

- (a) Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 2100, Schedule 301 or 340, as appropriate.
- (b) The field strength contours provided for in this section shall be considered for the following purposes only:
  - (1) In the estimation of coverage resulting from the selection of a particular transmitter site by an applicant for an FM broadcast station.
  - (2) In connection with problems of coverage arising out of application of [§ 73.3555](/cfr/47/73.3555.md).
  - (3) In determining compliance with [§ 73.315(a)](/cfr/47/73.315.md?p=a) concerning the minimum field strength to be provided over the principal community to be served.
  - (4) In determining compliance with [§ 73.215](/cfr/47/73.215.md) concerning contour protection.

## Notes

### Amendments

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 32 FR 11471, Aug. 9, 1967; 52 FR 10570, Apr. 2, 1987; 54 FR 9802, Mar. 8, 1989; 91 FR 29045, May 19, 2026]

### Authority

Authority: 47 U.S.C. 154, 155, 301, 303, 307, 309, 310, 334, 336, 339.

### Amendments

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 32 FR 11471, Aug. 9, 1967; 52 FR 10570, Apr. 2, 1987; 54 FR 9802, Mar. 8, 1989; 91 FR 29045, May 19, 2026]