Almost all AM detectors use Germanium diodes.
This link shows an interesting alternative:
http://www.wsdmag.com/Articles/Print.cfm?ArticleID=8628
Ge diodes have a typical Vf (forward conduction volage)
of .4V.
"Silicon Schottky diodes are commercially available
in four different versions. They offer forward
voltages of approximately 600 mV for high barrier,
330 mV for medium barrier, 280 mV for low barrier,
and 180 mV for zero-bias detectors.".

I am going to try and drive the detector diode in
my R2000 with a ~20K resistor feeding the junction
of to force the Ge diode slightly into conduction.
(for a diagram of the R2000 please see:
http://www.qsl.net/kc7bum/schematic-1.jpg
for a diagram of the R2000)

But I would prefer to find a diode with the lowest
Vf possible. Back in the mid 1970's GE had a diode
with a very low Vf, but I can't remember the name.

Does anyone know of a source of Shotkey "zero-bias
detector diodes"? And will diodes from a microwave
detector work in at 455KHz? I have several microwave
detector diodes that I would sacrfice in a minute if
there was a good chance they would work.

This weekend I intend to go to a friend to whom I have
loaned my ancient R392 which has a 455KHz IF out port,
and see how it works.


Terry