[Hammarlund] Anyone recognize this SP-600?

Mon Jan 31 07:42:23 EST 2022

I was a little too quick to pull the trigger on this one. After a cup of coffee, I realized that the upper right knob was a BFO knob, also the HFO and AVC controls are very similar to the JX-17 diversity variant. But the giveaway is the lack of anything in the right upper portion. That was typically where the Northern  Radio tags were placed.

So, Adam had it right. Usually the Northern Radio tags are left in place. Interesting antenna coupler under the receiver CU-1388/FLR-9 (V). Those were used in direction finding with the wuhlenwebber (sp?) antenna arrays.

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. 

I think that's what it is.

Les

----- Original Message -----
From: Les Locklear <leslocklear at hotmail.com>
To: Adam Vaughn <adamant316 at verizon.net>, <w2hx at w2hx.com>, <Hammarlund at mailman.qth.net>
Sent: 1/31/2022 6:30:22 AM
Subject: Re: [Hammarlund] Anyone recognize this SP-600?
________________________________________________________________________________

It's a Standard Hammarlund SP-600 J-4 No Xtal frequency control. Equipped with a 25 to 60 cycle (Hertz) power supply transformer. R-320a/FRC part of the OA-58B/FRC Radio Set. Signal Corps Order No. 21478-Phila-50-06. Also has separate IF gain control located where the Xtal Frequency Control was normally located.

Les

----- Original Message -----
From: Adam Vaughn via Hammarlund <hammarlund at mailman.qth.net>
Reply-To: Adam Vaughn <adamant316 at verizon.net>
To: <w2hx at w2hx.com>, <Hammarlund at mailman.qth.net>
Sent: 1/30/2022 8:05:16 PM
Subject: Re: [Hammarlund] Anyone recognize this SP-600?
________________________________________________________________________________

It appears to be one of the Northern Radio-modified SP-600s. Some of them were designated R-450/FRR-28; Northern themselves referred to it as "Type 159". Some more information about them can be found at the following addresses:
https://swling.com/blog/2017/03/exceedingly-rare-northern-radio-modified-sp-600/https://swling.com/blog/2017/03/dan-sheds-light-on-various-hammarlund-sp-600-models/https://www.navy-radio.com/rcvrs/frr28.htmhttps://www.boatanchors.org/NthnSP600.htm

Adam Vaughn
Collector of old computers, video game systems, radios and other electronic equipment...Visit my page athttp://www.electronixandmore.com/adam/index.html

-----Original Message-----
From: W2HX <w2hx at w2hx.com>
To: W2HX <w2hx at w2hx.com>; Hammarlund at mailman.qth.net <Hammarlund at mailman.qth.net>
Sent: Sun, Jan 30, 2022 8:32 pm
Subject: Re: [Hammarlund] Anyone recognize this SP-600?

Sorry, I forgot that this Hammarlund list doesn't accept photos
https://w2hx.com/x/What-Is-It/20220128_165444.jpg

Might be the only qth.net list left that doesn't!

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/c/w2hx-channel/videos

-----Original Message-----
From: hammarlund-bounces at mailman.qth.net <hammarlund-bounces at mailman.qth.net> On Behalf Of W2HX
Sent: Sunday, January 30, 2022 8:22 PM
To: Hammarlund at mailman.qth.net
Subject: [Hammarlund] Anyone recognize this SP-600?

It is not JX model, it is not quite a -17 model. Anyone recognize it?

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/c/w2hx-channel/videos

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