On a sunny day (Thu, 02 Apr 2015 09:10:47 -0500) it happened amdx
wrote in :

I'm about to build this circuit to compare output from different
ferrite receive antennas. I will be using it with the the FET amplifier
referenced at the bottom of the page, so the input impedance is not a
concern. I'm mostly interested in the DC output to monitor signal
levels. AM band frequencies.

http://www.crystal-radio.eu/diodedet...dedetector.htm

Any fix for the sinewave distortion in the second and third scope traces.
Mikek

If you really want to be linear for small voltages at ferrite rod frequencies
then a small opamp diode detector would be a lot better.

http://en.wikipedia.org/wiki/Precision_rectifier