[R-390] Interesting receiver

[John Kolb]

The main driving force behind the R-1051 was the Navy's shift in the 
mid 60's to multiplexed RTTY transmissions
for most ships. These had from 4 to 16 as I recall separate RTTY data 
channels within one signal, with 85 Hz shift.
Thus they had to be tuned within a couple of Hz accuracy.  The 
alternatives to the 1051 were the WRR-2 aka FRR-59,
or R-390's with CV-157 converters, either of which would have been a 
real nightmare to maintain.

One of my fondest memories as a Navy radioman was calling an ET up to 
fix one of our 1051's, watching him
replace each of the modules from the spares kit, one at a time - 
radio still bad - putting all the pulled modules
into a working 1051 - still working.  While he was scratching his 
head, I tilted up the 1051, looked at the chassis
underside, and spotted where one of the wires/connector pins had 
popped out of the connector backshell.  But
most problems could be fixed by a relatively untrained ET with a set 
of good modules.

We received a pair of 1051's during our 1965 rebuild for use with the 
forthcoming mux transmissions, but
received R-390A's with CV-591's for use with SSB.

Before the introduction of the 1051, only a few ships were equipped 
for mux transmissions.  My prior ship,
the Commander 7th Fleet flagship was, with direct mux transmissions 
to and from whichever shore station
was closest as we moved around. Had a pair of FRR-39's??? 41's??? 
which was a relay rack with 2 R-390's and
2 CV-157's.

John

At 12:02 PM 10/23/2006, Cecil Acuff wrote:

>I agree it's an engineering marvel...one that replaced an 
>engineering marvel the R-390 series.  But in terms of performance, 
>outside of frequency stability and SSB demodulation, it's pure 
>receive performance is bettered by a good R-390A...probably even a 
>good SP-600.  The R-1051 suffered from a lot of internal 
>noise...it's full of germanium transistors.  I heard in the later 
>years it was costing the military around 30K each for the G and H 
>models.  That was probably in the 80's if I were to venture a guess.
>
>Cecil....



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