---
kind: "section"
citation: "47 C.F.R. § 90.689"
title: "47"
number: "90.689"
heading: "Field strength limits."
url: "https://uscodex.org/cfr/47/90.689"
---

# §90.689. Field strength limits.

- (a) For purposes of implementing [§§ 90.689 through 90.699](/cfr/47/90.689..90.699.md), predicted 36 and 40 dBµV/m contours shall be calculated using Figure 10 of [§ 73.699](/cfr/47/73.699.md) of this chapter with a correction factor of −9 dB, and predicted 18 and 22 dBµV/m contours shall be calculated using Figure 10a of [§ 73.699](/cfr/47/73.699.md) of this chapter with a correction factor of −9 dB.
- (b) The predicted or measured field strength at any location on the border of the EA-based service area for EA licensees must not exceed 40 dBuV/m unless all bordering EA licensees agree to a higher field strength. In the event that this standard conflicts with the EA licensee's obligation to provide co-channel protection to incumbent licensees pursuant to [§ 90.621(b)](/cfr/47/90.621.md?p=b), the requirements of [§ 90.621(b)](/cfr/47/90.621.md?p=b) shall prevail.

## Notes

### Amendments

[61 FR 6158, 6159, Feb. 16, 1996, as amended at 62 FR 41216, July 31, 1997]

### Authority

Authority: 47 U.S.C. 154(i), 161, 303(g), 303(r), 332(c)(7), 1401-1473

### Source

Source: 43 FR 54791, Nov. 22, 1978, unless otherwise noted.

### Amendments

[61 FR 6158, 6159, Feb. 16, 1996, as amended at 62 FR 41216, July 31, 1997]