Sec.  80.773   Co-channel interference protection.

   (a) Where a VHF public coast station geographic area licensee shares a
   frequency with an incumbent VHF public coast station licensee, the ratio of
   desired to undesired signal strengths must be at least 12 dB within the
   service area of the station.

   (b) Where a VHF public coast station geographic area licensee shares a
   frequency with an incumbent private land mobile radio licensee, the VHF
   public coast station geographic area licensee must provide at least 10 dB
   protection to the PLMR incumbent's predicted 38 dBu signal level contour.
   The PLMR incumbent's predicted 38 dBu signal level contour is calculated
   using the F(50, 50) field strength chart for Channels 7–13 in  Sec. 73.699 (Fig.
   10a) of this chapter, with a 9 dB correction factor for antenna height
   differential, and is based on the licensee's authorized effective radiated
   power and antenna height-above-average-terrain.

   (c) VHF public coast station geographic area licensees are prohibited from
   exceeding a field strength of +5 dBu (decibels referenced to 1 microvolt per
   meter) at their service area boundaries, unless all the affected VHF public
   coast station geographic area licensees agree to the higher field strength.

   [ 63 FR 40065 , July 27, 1998, as amended at  64 FR 26887 , May 18, 1999]

Subpart Q [Reserved]

Subpart R—Technical Equipment Requirements for Cargo Vessels Not Subject to
Subpart W