[R-390] CV-591

[Drew Papanek]

Tom Warren wrote:
>
>There's also another possibility.  You know that the 455 kHz output of the
>RF deck comes as a balanced pair.   Only one side of the balanced pair is
>used for the 2, 4, 8, and 16 kHz positions of the bandwidth switch.  Thus
>you can take the other mini-BNC connector (P518) and feed that to the IF
>output jack.  Then if you have that connection loaded by a high impedance
>input to the Eldico (if in fact the input impedance of the Eldico is high),
>then everything works fine.  Depends on the sensitivity of the Eldico also.
>This technique works just fine with my Siemens D2007 Frequency Selective
>Voltmeter used in its high impedance mode and as a SSB IF strip and
>demodulator.  Then you can compare the SSB performance of the R390A versus
>the Frequency Selective Voltmeter  --  and the comparison isn't too bad.
>Yep, my FSV sounds better just like 30-year-later technology should, but 
>not
>embarassingly better.
>
>Tom, W4PG

Tom,

Good idea!  Using one side of the balanced IF feed (and forsaking use of 
R-390A crystal filter) opens up a large number of interface possibilties, 
panadaptor comes to mind.  Neat, clean, and no mods required.

Is the R-390A AGC stock and in good shape (oil-filled cap not leaking)?  Or 
do you have the 2 diode time constant mod (Dallas Lankford) or the much 
discussed line audio into bridge rectifier into AGC line.  Does the FSV have 
any AGC action?

Drew

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