[Elecraft] K3: AM Reception

[Lyle Johnson]

I have run a number of tests on my K3 regarding low-level "BFO-like" 
whistles reported during AM reception.

Signals less than -16 dBm (57 dB over S9) do not exhibit this behavior, 
but signals above this strength do.

For the time being, if you are listening to an AM station that is this 
huge, please be sure PRE is OFF and ATT is ON.  In my case, the 
low-level heterodyne did not appear until the signal at the antenna jack 
was at -6 dBm (S9 + 67 dB).

Further, if the K3 is tuned to the station's carrier frequency, the 
low-level heterodyne becomes inaudible.

If the signal is stronger than this, disconnect your antenna!  You 
should still be able to hear the station :-)

Seriously, we'll investigate further to see what can be done about this. 
  But in the meantime, please understand that only huge signals exhibit 
the symptom, and then only if you are not tuned to the station's carrier 
frequency.

73,

Lyle KK7P