[Skimmertalk] Images with VHF ensemble softrock

Mark n2qt n2qt at verizon.net
Thu Aug 11 07:20:41 PDT 2011


When using my 6M Softrock VHF ensemble II with Skimmer I was initially 
plagued with third order spurious responses.  (i.e. a strong station 
would be spotted at multiple frequencies and the image would move at
threee times the rate of changes to interfering signal).  The input levels 
were still below the clipping point on the softrock output opamps.  The 
traditional image rejection appeared to be pretty good at 50 db or so.  
Adjusting the audio level into the sound card did not affect it. 

This is using a Infrasonic Quartet sound card under XP.  What I found was
changing to the WDM from MME eliminated the images.   

I pass this info along both to see if someone has an explanation as well 
as save others from this issue.

Mark n2qt



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