Using Schottky diodes in AM detectors

[wa2ise]

Schottky and similar diodes have a much lower diode drop, even lower than germanium diodes. Some can be as low as 0.15V. Which would make for a decent detector for weaker signals. Schottky diodes have internal capacitance, but it's about the same or less than silicon detector diodes. . A quick way to tell if a Schottky diode would work in your radio is to connect it in parallel with the existing silicon diode (0.7V drop). However, the AVC circuit may get out of balance with the lower diode drop diode. Using the old silicon diode just for the AVC circuit makes it work as it did before. This also makes for a better audio detector circuit, as the back bias from the AVC cap will not be seen by the audio detector circuit. So we have two diodes, a silicon diode for the AVC, and a Schottky diode for the audio signal. This should make for better detected sound from weaker stations.