47 CFR 80.273 - Radar standards.
(a) Radar installations on board ships that are required by the Safety Convention or the U.S. Coast Guard to be equipped with radar must comply with the following standards (all incorporated by reference, see § 80.7):
(1) IEC 60945;
(2) IEC 62388;
(3) IMO Resolution A.694(17), as revised by IMO Resolution MSC.149(77);
(4) IMO Resolution MSC.191(79);
(5) IMO Resolution MSC.192(79); and
(6) ITU-R M. 1177-3.
(b) For any ship of 10,000 tons gross tonnage and upwards or that is otherwise required to be equipped with two radar systems, each of the two radar systems must be capable of operating independently and must comply with the specifications, standards and general requirements set forth on paragraph (a) of this section. One of the systems must provide a display with an effective diameter of not less than 320 millimeters (12.6 inches), (16-inch cathode ray tube). The other system must provide a display with an effective diameter of not less than 250 millimeters (9.8 inches), (12-inch cathode ray tube).
(c) Radar installed before March 25, 2008 must meet and be maintained to comply with the Commission's regulations in effect for the equipment on the date of its installation.