[Boatanchors] Seeking Info: WWI German Crystal Set

[Al Klase]

Here's a link to drawings of a WWI German crystal set done by the U.S.
Army Signal Corps, Research and Inspection Division in France in 1918.
Coincidentally this was the unit to which Edwin Armstrong was attached
when he developed the superheterodyne.  See:
http://users.erols.com/oldradio/eha13.htm

This radio is similar in size and function to the French A-1 set that
evolved into the Signal Corps BC-14.and BC-14A.  See:
http://users.erols.com/oldradio/eha8.htm

However, after designing a number of high-performance crystal radios,
and recently restoring and evaluating a BC-14A, I strongly suspect that
the German set is a considerably better radio.  E.g., notice that the
designer had enough insight to tap the detector down to the secondary
tuned circuit to get sharper tuning and more sensitivity.  This is the
earliest implementation of this circuit topology of which I am aware.
This arrangement also allowed the calibration of the secondary tuning
capacitor, rather than depending on a separate wavemeter as in the
French A-1.

Does anyone have any further information on this radio?

Regards,
Al

-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/