47 CFR 80.1129 - Locating and homing signals.
(a) Locating signals are radio transmissions intended to facilitate the finding of a mobile unit in distress or the location of survivors. These signals include those transmitted by searching units and those transmitted by the mobile unit in distress, by survival craft, by float-free EPIRBS, by satellite EPRIBs, and by search and rescue radar transponders to assist the searching units.
(b) Homing signals are those locating signals which are transmitted by mobile units in distress, or by survival craft, for the purpose of providing searching units with a signal that can be used to determine the bearing to the transmitting stations.
(c) Locating signals may be transmitted in the following frequency bands: 117.975-136 MHz, 121.5 MHz, 156-174 MHz, 406-406.1 MHz, and 9200-9500 MHz.
(d) The 9 GHz locating signals must be in accordance with ITU-R M.628-4 (incorporated by reference, see § 80.7), as specified in § 80.1101.