Section 90.689 - Field strength limits(a) For purposes of implementing §§ 90.689 through 90.699 , predicted 36 and 40 dB[MICRO]V/m contours shall be calculated using Figure 10 of § 73.699 of this chapter with a correction factor of -9 dB, and predicted 18 and 22 dB[MICRO]V/m contours shall be calculated using Figure 10a of § 73.699 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) , the requirements of § 90.621(b) shall prevail.61 FR 6158, 6159, Feb. 16, 1996, as amended at 62 FR 41216, July 31, 1997