[Hammarlund] ITT modified SP-600

[Richard Knoppow]

-----Original Message-----
>From: Les Locklear <leslocklear at hotmail.com>
>Sent: Aug 29, 2014 10:25 AM
>To: Bob Camp <kb8tq at n1k.org>, kgordon2006 at frontier.com
>Cc: Hammarlund at mailman.qth.net
>Subject: Re: [Hammarlund] ITT modified SP-600
>
>This was taken from the Hammarlund SP-600 models page:
>
>Another variant was the R-450/FRR-28. These were standard Hammarlund JX 
>receivers that were modified by Northern Radio; USN stock no. F 
>16-Q-112117-200, contract number Nobsr-52132, 19 December, 1950. These were 
>designated SP-600-MX. Installed in a relay rack cabinet with a LS-187/UR 
>speaker, AM-615/UR amplifier detector, KY-79 keyer, O-165/UR high stability 
>oscillator, S-224/UR patch panel and an AN/URA-8 fsk converter-comparator. 
>The X-tal frequency control at the top r.h corner was removed and covered 
>with a Buships/Northern Radio order no. nameplate. Northern Radio located in 
>New York City made many modifications available for SP-600's such as an IF 
>gain control located where the dial lock was normally located. This was a 
>very common military modification.
>
>Les
>
>-----Original Message----- 
>From: Bob Camp
>Sent: Friday, August 29, 2014 12:20 PM
>To: kgordon2006 at frontier.com
>Cc: Hammarlund at mailman.qth.net
>Subject: Re: [Hammarlund] ITT modified SP-600
>
>Hi
>
>F.S. TELEG = Frequency Shift (Keying) Telegraphy. More commonly known as 
>FSK.
>
>Bob
>
>On Aug 29, 2014, at 12:17 PM, Kenneth G. Gordon <kgordon2006 at frontier.com> 
>wrote:
>
>> Well, the data-plate associated with the BFO says, "MOD FOR I.S.B. AND
>> F.S. TELEG."
>>
>> I know that ISB is Independent Side Band, but what, exactly, is F.S. 
>> TELEG?
>> Some sort of RTTY, I would suppose.
>>
>> Anyway, it is very interesting, and the receiver looks to be in excellent
>> condition. I wish we knew fuller details of the mod.
>>
>> Price is way too much for me, though.
>>
>> Ken W7EKB
    I think this was a sort of predecessor to the JX-17 intended for use in dual diversity operation with external control of all oscillators.  ISB and FSK was done with external converters.  I am pretty sure there is a handbook or at least schematic for the Northern Radio version on line but am at work now so can't find it.