[ARC5] Novice receivers.

[Richard Knoppow]

     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