[ARC5] Novice receivers.

[Fernando - LU2DFM]

Thank you very much.  I was with the wrong notion that the SP-200 was
elarlier than th HQ-120. 


On Mon, Nov 16, 2015 at 03:06:19PM -0800, Richard Knoppow wrote:
>     Yes, if you look at the Super-Pro data sheets you will find that before
> about 1940 a crystal filter was offered as an add on but the design was
> quite different. It was to be blunt crude, probably a work around of the
> original Lamb patent.
>    I mis-spelled the name, it is Oram.  The patent can be found at:
> 
> http://www.google.com/patents/US2222043
> 
>     The application date is 1939, issued in 1940.  The HQ-120-X was the
> first receiver to employ this circuit. It was also offered as the HQ-120 (no
> X) without the filter but I think very few were sold so the filter became
> standard.
> 
>    James J. Lamb had several patents on crystal filters, for instance:
> 
> 
> US 2156786 A
> and
> US 2054757 A   which I think was the original.
> 
>     You may also want to look at:
> 
> US 2101549 A
>     Lamb's patent on the noise blanker.
> 
> On 11/16/2015 1:32 PM, Fernando - LU2DFM wrote:
> >On Mon, Nov 16, 2015 at 01:20:25PM -0800, Richard Knoppow wrote:
> >
> >>This same filter, invented by Donald Orem, the chief engineer of Hammarlund,
> >>was introduced on the HQ-120-X and was eventually used in the Super-Pro. The
> >I always though that it was the other way around, since my understanding
> >is that the Super Pro predates the HQ-120 for some years.
> >
> >Can you expand on this?
> >
> >Many thanks.
> >
> 
> -- 
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
> 
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-- 
73 de Fer, LU2DFM