[Elecraft] K3S RX ANT COR?

[Michael Carter]

Eric,

The schematic for the KXV3B-2 BNC Board
shows a COR and associated RF detector
circuitry for the RX ANT IN port.  There
is also a protective spark gap on that
input, presumably for lightning induced
voltages on the RX antenna.

I haven't checked the K3s manual,
but the RF detector circuit uses
a Schottky rectifier/peak detector
circuit to switch an NPN Darlington
pair that controls the COR coil.  I
estimate about 1.5 volts peak
RF on the RX ANT input would
trigger the COR and disconnect
the RX ANT input from the rest
of the RX signal processing chain.

73,
Mike, K8CN