47 CFR § 73.6010 - Class A TV station protected contour.
(a) [Reserved]
(b) The Class A TV station protected contour is calculated from the effective radiated power and antenna height above average terrain, using the F(50,50) charts of Figure 9, 10 or 10b of § 73.699 of this part.
(c) A digital Class A TV station will be protected from interference within the following predicted signal contours:
(1) 43 dBu for stations on Channels 2 through 6;
(2) 48 dBu for stations on Channels 7 through 13; and
(3) 51 dBu for stations on Channels 14 through 36.
(d) The digital Class A TV station protected contour is calculated from the effective radiated power and antenna height above average terrain, using the F(50,90) signal propagation method specified in § 73.625(b)(1) of this part.
(e) A digital Class A DTS station will be protected from interference within its Class A DTS protected area as defined by § 73.6023(d).