[Hammarlund] Hammarlund SP-600 History Item

Sun Sep 7 19:40:19 EDT 2014

Since I was only about 3 at the time I don't know, but....  
  The old Super Pro was basically a 1936 design, and had stability problems, as well as image problems.  In the late 40s some of the BC779s were modified to add crystal control for point-to-point RTTY, which solved the stability problem and foreshadowed the -JX version of the SP-600. 
I suspect Hammarlund's SP-600 was a natural progression of the SP 200/400 design, technology which their engineers were very familiar with, and they were desperate to get a replacement for the aging SP-400.  I would guess that Collins had a pretty secure patent position on their dual conversion with PTO design.  In any event, Hammarlund didn't adopt the crystal controlled front end until the HQ215, which was too late.

Hammarlund must have had a pretty good handle on customer desires, however, they sold a LOT of SP-600s (until the R-390 came along).

Ed W2EMN

-----Original Message-----
From: James A. (Andy) Moorer <jamminpower at earthlink.net>
To: hammarlund <hammarlund at mailman.qth.net>
Sent: Sun, Sep 7, 2014 6:37 pm
Subject: Re: [Hammarlund] Hammarlund SP-600 History Item

I don't know, but here's what I would guess:
Their competition was the RBB, the AR-88, and the SX-28. All 
single-conversion. The SP-400 was quite a good seller to the military 
(as the BC-779). I would not be surprised if there wasn't a big Signal 
Corps contract that came up and they needed a competitive advantage. The 
SP-600 looked and behaved a lot like the BC-779, but it was (is) 
double-conversion. It was probably the cheapest, easiest hack they could 
come up with to make a double-conversion receiver to give them a 
significant competitive advantage. The imaging in single-conversion 
receivers had been a continual drumbeat for a couple of decades, made 
worse by the development of transmitting tubes that could actually hit 
that high range (above maybe 20 MHz). Now why they went to the turret 
assembly, rather than the switched arrangement of the above-mention 
receivers I will never know.

Just my opinion, of course.
Any other opinions? Chime in, folks.
-A

On 9/7/2014 4:06 PM, Richard Knoppow wrote:
> ----- Original Message ----- From: <jdteske at verizon.net>
> To: <Hammarlund at mailman.qth.net>
> Sent: Wednesday, September 03, 2014 6:08 AM
> Subject: [Hammarlund] Hammarlund SP-600 History Item
>
>      I sent Jon a rather rambling recollection of what I know about 
> the history of the SP-600 but realize that there is a lot I don't 
> know.  I wonder if anyone on this list has any inside information 
> about why Hammarlund decided to make this receiver. They advertized 
> it, sort of, in about 1948 in the back of the ARRL handbook, the ad 
> features a picture that is probably either a drawing or a heavily 
> retouched photo of a mock-up or prototype. The specs and tube list are 
> rather different from what was actually sold a couple of years later.  
> Collins seems to have have gotten the beat on a double-conversion 
> receiver with the 75A-1 and shortly thereafter the 51J-1, the general 
> coverage version. The SP-600 is a more conventional design in that it 
> uses a fixed second conversion oscillator and a tunable first 
> conversion oscillator where the Collins receivers use crystal 
> controlled first conversion and a tunable second conversion 
> oscillator, essentially a tunable IF. Since the two receivers must 
> have been in the works at about the same time one wonders about what 
> inspired each of them.  The history of anything can't be understood in 
> isolation so I think some understanding of the economic conditions of 
> the just post-war time is of some interest. Remember that there was a 
> pretty severe re-adjustment to peace time conditions with rather rapid 
> inflation and a lot of labor trouble.  Many companies who had been 
> living on government contracts found them suddenly discontinued.  I 
> suspect Hammarlund must have been struggling a bit.  Remember that 
> this is around the time the HQ-129-X was announced (at $129) only to 
> be discontinued very quickly and then re-released after several months 
> at a higher price.  What, I wonder, was going on at Hammarlund.
>
>
> -- 
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com
>

-- 
James A. (Andy) Moorer
www.jamminpower.com

______________________________________________________________
Hammarlund mailing list
Home: http://mailman.qth.net/mailman/listinfo/hammarlund
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Hammarlund at mailman.qth.net

List Administrator: Duane Fischer, W8DBF
** For Assistance: dfischer at usol.com **

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html