[Milsurplus] Collins 75A-4 Receiver Coverage

[Al Klase]

Guys,

I was kinda in and out of this thread, so I'm not sure I addressed the 
right issue in my recent post.  I was probably not thinking in the 
proper time frame.    I guess the important thing was SSB capability: 
frequency stability, proper filtering, and a product detector.  That's 
the 75A4 that showed up about 1955.

I guess they could have done the job with and R-390 and CV-157 
converter, but that's heavy and expensive.  I'm also not sure when the 
converters like CV-157 and CV-591 were introduced.

Al

Al Klase wrote:
> WA5CAB at cs.com wrote:
>   
>> I thought someone else would have asked this err now but the obvious 
>> question is why buy the limited coverage 75A variant instead of the 
>> 51J?.......
>>     
> Hi Robert,
>
> I think the answer is that the 75A was introduced in 1946.  (per Moore, 
> 3ed Edition)  This was the first commercial double-conversion superhet 
> with a crystal controlled first oscillator.  This gave it unprecedented 
> frequency accuracy.  The 51J was developed from the 75A and wasn't ready 
> until 1949. 
>
> Like someone said:  The 75A was a stop-gap measure for the military.  
> They really wanted general coverage.
>
> Regards,
> Al
>
>   
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/