[Elecraft] K2 SN 25xx has very low sensitivity in 20 and 80m bands

[Michael Carter]

Hi Chris,

Does your K2 transmit OK on those bands, i.e. at full power output?

The fact that other bands have normal sensitivity indicates
that the main receiver functional blocks are OK.  The bandpass
filters for 20 and 80 meters have only one component in
common, relay K3, but that relay selects 80/160 meters or separately
20/30 meters by adding additional shunt capacitors for the
lower frequency band in the proper filter section.

I would check your per-band settings to be sure that you
haven't inadvertently selected an antenna port
that isn't connected to the proper antenna for one of those
bands OR that a separate RX ANT is selected when you
have no antenna on that port (presuming you have the
160 meter/RX ANT module installed).

73,
Mike, K8CN