Sec.  90.263   Substitution of frequencies below 25 MHz.

   Frequencies below 25 MHz when shown in the radio pool frequency listings
   under this part will be assigned to base or mobile stations only upon a
   satisfactory showing that, from a safety of life standpoint, frequencies
   above 25 MHz will not meet the operational requirements of the applicant.
   These frequencies are available for assignment in many areas; however, in
   individual cases such assignment may be impracticable due to conflicting
   frequency use authorized to stations in other services by this and other
   countries. In such cases, a substitute frequency, if found available, may be
   assigned from the following bands: 1705–1750 kHz, 2107–2170 kHz, 2194–2495
   kHz, 2506–2850 kHz, 3155–3400 kHz, or 4438–4650 kHz. Since such assignments
   are in certain instances subject to additional technical and operation
   limitations, it is necessary that each application also include precise
   information  concerning transmitter output power, type and directional
   characteristics, if any, of the antenna, and the minimum necessary hours of
   operation. (This section is not applicable to the Radiolocation Service,
   subpart F of this part.)

   [ 72 FR 35196 , June 27, 2007]