[Elecraft] [K3] 'Birdies' on 6M when adjusting filters

[Michael Eberle]

A few days ago I installed the new KSYN3A modules in my K3 along with 
the KXV3B modules.  I am running FW Rev 5.26.  I was at 50.267 running 
JT65 with no problems and the BW was at 2.8 KHz - the low cut at 0.1 and 
the high at 2.9.  When I adjusted the low end up to 0.3 a 'birdie' all 
of a sudden appeared toward the low end of the audio pass band along 
with a corresponding spike on the P3.  As I adjust the low cut up, each 
time the spike jumps further up the audio pass band.  As I adjust the 
cut above 0.8 the spike keeps moving up out of the audio pass band.  I 
can see it moving up the spectrum on the P3.

With the VFO at 50.276 and the low cut at 2 KHz the spike appears at 
about 50.285 as measured on the P3.

Not sure if it has anything to do with the new synth modules or the 
KXV3B.  I turned the preamp off but it makes no difference except for 
the background noise.  I tried the same thing on 10 and 12 meters but it 
does not happen on those bands.

Thanks,
Mike - KI0HA