[Boatanchors] National NC-183D(R) Diversity version?

[flood at Krohne.com]

Greetings,

A rack mount NC-183D was one of the BA's that followed me home from the
Hosstraders flea in NH this weekend.  This is an odd one.  It has what
seems to be a "factory" diversity modification.  There are two additional
knobs on the front panel, one just to the right of the bandspread  that
selects an internal or external HFO and another just to the left of the
main tuning control for AFC with four positions, two for a local BFO with
slow and fast settings as well as slow and fast settings for a remote BFO.
The "Bandswitch" is different (from what I remember) and has four marked
positions 12-31MC, 4.4 - 12MC, 1.6 - 4.4MC, and BCST.  (The control
actually has six detents.)  The back panel has loads of "Extra" parts A
three position osc. selector, a local / div. (diversity?) toggle switch
,ext BFO and 1250KHZ OSC. inputs,  IF and Monitor outputs all located on
SO-239 connectors, as well as a LF gain pot..  All markings on the front
panel (mil. gray) are engraved or stamped, filled with white.  There are
four small holes in the upper left of the front panel most likely for a
(missing) data tag.  It is functional and on frequency as best as I can
tell using known stations as a reference.  The strange thing, is that it
has the "normal" NC183-D main and Ham band, bandspread dials.  The general
thought at the flea (by those of us looking at it being shell shocked from
lack of sleep and lighter wallets) was that perhaps it may be a prototype
for a military project.  Can anyone on the list help me with more info on
this beast.  Or perhaps it is common and I have lead a sheltered life.  I
hope to have some digital photos available later today for those
interested.

John Flood KB1FQG
TASC Department
KROHNE, Inc
7 Dearborn Rd.
Peabody, MA   01960
Tel.:  978-535-6060 / 800-356-9464
Fax:   978-535-8180