Further information most welcome, thank-you

In the 1948 Radio handbook which I mentioned previously, there are adverts
from a company by the name of Millen, and I assumed it was the same guy
after he had left National.

Your comment about a phenolic intersperser is no doubt some means of
isolating an
earthy contact?

It would be interesting to know from the Lamb patent whether he proposed
therein the
technique of Single Signal Reception by the use of the phasing control to
null
out the audio image, or whether this was something that came about through
experience?


"Richard Knoppow" wrote in message
m...

"gareth" wrote in message
...
WOW!

A very full response, thank-you.


After I posted this I realized that I forgot a part. In the Super-Pro
there is a phenolic lever between the rotating cam and the rods from the
movable coils. I am not sure why the rods are not moved directly by the
cams. I think Hammarlund had a patent on the IF variation system but I
don't have the number. The Hammarlund crystal filter is described in _QST_
Dec 1938, p.33 D.K. Oram "Full Range Selectivity with the 455 khc Crystal
Filter" Oram's patent is USP 2222043 You can get patents by number from
the U.S. Patent and Trade Mark Office or from Google Patents. The Google
site has the advantage that patents are searchable by text for _all_ dates
and are available in PDF form.
I also have the Lamb patents but it will take some searching since my
file is organized by patent number and not title. However, they are easily
found by doing a Google search for James Lamb. You will also find his
patent for the famous Lamb Noise Blanker. Lamb had more than one patent on
crystal filters and wrote extensively about them in the early thirties
editions of QST. AFAIK, the first application of the Lamb filter was in
the HRO. The first Hammarlund filter was in the HQ-120-X and it was later
applied to the Super-Pro. Some Series 100 Super-Pros have crystal filters
as an add-on but these are not the later version. BTW, the Lamb patent
was licensed to James Millen. At the time he was one of the principles of
the National Radio company and is supposed to have been responsible for
the mechanical design of the HRO.


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Richard Knoppow
Los Angeles
WB6KBL