[Premium-Rx] R1451A

[Al Klase]

Used on submarines for signal intelligence (SIGINT).  Part of AN/WRL-6.  
A little info here: 
http://en.wikipedia.org/wiki/Signals_intelligence_operational_platforms_by_nation
Scroll down to "United States: Submarine Platforms."

If anyone has "Jane's Military Communications" from back in the 1980's 
it might be worth a look.

Al


On 1/1/2013 6:41 AM, Michael O'Beirne wrote:
> Dear Bill
>
> I have looked at the only reference on the net to this set.  A 
> distinct physical resemblance to the Telefunken e893 submarine radio.
>
> What was of concern was the 40dB aerial attenuator switch.  Such high 
> attenuation inevitably suggests that the signal handling range was 
> limited - as one expects with early transistorised receivers.
>
> Do you know which parts of the USN used it?  The compact size suggests 
> perhaps for submarines or small warships, given that the large 
> warships were happy to accommodate a battery of big heavy R390As.
>
> 73s
> Michael
> G8MOB
>
> ----- Original Message ----- From: "Bill Tweedie" 
> <bill.tweedie at bigpond.com>
> To: <Premium-Rx at mailman.qth.net>
> Sent: Tuesday, January 01, 2013 3:18 AM
> Subject: [Premium-Rx] R1451A
>
>
>> Hi All
>> For those who are interested-
>> This set appears to differ somewhat from the VLF version.
>> Single conversion fron 0.5 MHz to 8 MHz with 455 KHz IF with filters 
>> from 0.1KHZ TO 16 KHZ.
>> Double conversion from 8 MHz to 32 MHz. First IF is 3.455MHz ( incl a 
>> 'roofing filter' at 3.455MHz)
>> then 455 KHz through 455KHz filters to selectable AM and product 
>> detectors.
>> Has an ISB facility with two mechanical filters, one for each 
>> sideband in addition to the above filters.
>> Has a fixed 455KHz BFO plus a variable facility from -8 KHz to +8 KHz.
>> FET front end with two RF stages & attenuator.  Extensive shielding 
>> section by section.
>> It is likely that oscillator radiation was minimal fro obvious reasons.
>> AGC & manual controls. Construction is a work of art. Circuit boards are
>> Would have cost a fortune to produce in the 1960s.
>> Bill
>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/