; REFREQ
;---------------------------------------------------------------
;! Specifies the frequency to be uased as the reference
;# ADVERB SPECTRAL ANALYSIS
;-----------------------------------------------------------------------
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;-----------------------------------------------------------------------
REFREQ    LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
REFREQ
Type:  Adverb  (Scalar)
Use:   Specifies the frequency to be used for the reference
Null value:  0 -> found from the data
Tasks:
   HOLOG....Read & process holography visibility data to telescope
            images.   REFREQ is the reference in GHz.
   SOUSP....Fits source spectral index from SU table or adverbs.
            REFREQ specifies the reference in GHz, 0 -> 1 GHz,
            < 0 -> data header frequency
   SPIXR....Fits spectral indexes to each row of an image incl
            curvature.  REFREQ specifies the reference in GHz,
            0 -> 1 GHz, < 0 -> data header frequency
----------------------------------------------------------------
