[Elecraft] K3 Signal blocking inside of the crystal filter BW

[Dave Anderson, K4SV]

Hi All,

I recently purchased a brand new K3 and after a factory tuneup, it is a very nice radio.

I discovered a situation using it that I would like to mitigate.

When trying to work a station simplex in a pileup I experienced receiver blocking.  While trying to listen to the DX station others were calling so I narrowed the passband down to 200hz.  I was unable to copy the weaker station very well because the louder stations were retarding the AGC.  This blocking is common to AF DSP radios like a IC746 but I would have not expected it to occur on the K3.  I have owned a IC7800 for 5 years and even though the lab tests show it to be not as good as the K3 I have never experienced blocking inside of the selected passband like I have seen on my K3.

I found if the DSP is set the same as the 400Hz crystal filter ,I have 8 pole, the blocking does not occur.  But larger signals inside of the crystal filter BW makes copy hard.

Is there a way to fix this?  Perhaps a setup value change or something.  I purchased this radio to take on DXpeditions.  At this point I not sure if I could reduce the BW using the DSP inside of the 400Hz filter without problems.

Thanks in advance,
 
Dave Anderson, K4SV
Tryon, NC
 828 777-5088
 
www.K4SV.com