Sec.  90.237   Interim provisions for operation of radioteleprinter and
radiofacsimile devices.

   These  provisions authorize and govern the use of radioteleprinter and
   radiofacsimile devices for base station use (other than on mobile-only or
   paging-only  frequencies)  in  all  radio  pools  and  services except
   Radiolocation in this part.

   (a) Information must be submitted with an application to establish that the
   minimum separation between a proposed radioteleprinter or radiofacsimile
   base station and the nearest co-channel base station of another licensee
   operating a voice system is 120 km (75 mi) for a single frequency mode of
   operation, or 56 km (35 mi) for two frequency mode of operation. Where this
   minimum mileage separation cannot be achieved, either agreement to the use
   of  F1B,  F2B, F3C, G1B, G2B or G3C emission must be received from all
   existing co-channel licensees using voice emission within the applicable
   mileage  limits, or if agreement was not received, the licensee of the
   radioteleprinter or radiofacsimile system is responsible for eliminating any
   interference with preexisting voice operations. New licensees of voice
   operations will be expected to share equally any frequency occupied by
   established radioteleprinter or radiofacsimile operations.

   (b) [Reserved]

   (c) Transmitters certificated under this part for use of G3E or F3E emission
   may  also  be  used  for  F1B,  F2B, F3C, G1B, G2B or G3C emission for
   radioteleprinter or radiofacsimile, provided the keying signal is passed
   through  the  low  pass audio frequency filter required for G3E or F3E
   emission.  The  transmitter  must be so adjusted and operated that the
   instantaneous frequency deviation does not exceed the maximum value allowed
   for G3E or F3E.

   (d) Frequencies will not be assigned exclusively for F1B, F2B, F3C, G1B, G2B
   or  G3C  emission for radioteleprinter or radiofacsimile (except where
   specifically provided for in the frequency limitations).

   (e)  The requirements in this part applicable to the use of G3E or F3E
   emission are also applicable to the use of F1B, F2B, F3C, G1B, G2B or G3C
   emission for radioteleprinter and radiofacsimile transmissions.

   (f) The station identification required by  Sec. 90.425 must be given by voice or
   Morse code.

   (g) For single sideband operations in accordance with  Sec. 90.266, transmitters
   certified under this part for use of J3E emission may also be used for A2B
   and F2B emissions for radioteleprinter transmissions. Transmitters certified
   under this part for use of J3E emission in accordance with  Sec.  Sec. 90.35(c)(1)(A),
   90.35(c)(1)(B), 90.35(c)(1)(C) and 90.257(a) may also be used for A1B, A2B,
   F1B, F2B, J2B, and A3C emissions to provide standby backup circuits for
   operational telecommunications circuits which have been disrupted, where so
   authorized in other sections of this part.

   [ 43 FR 54791 , Nov. 22, 1978, as amended at  49 FR 48712 , Dec. 14, 1984;  51 FR 14998 , Apr. 22, 1986;  62 FR 18927 , Apr. 17, 1997;  63 FR 36610 , July 7, 1998;
    63 FR 68965 , Dec. 14, 1998;  72 FR 35195 , June 27, 2007]