[K3] RE: [Elecraft] How do you measure filter offset

[Bill W4ZV]

Tom W8JI wrote:
> 
> 
> If I wanted to center and match a typical SSB or CW filter 
> for passband centering,  I'd use something like 5 or 10 dB. 
> I wouldn't match them at a higher attenuation because it 
> really doesn't mean anything and can be very misleading and 
> cause the actual useful centers to be misaligned.
> 
> It really should just be at some attenuation that is much 
> greater than the ripple amount, but not so far down on the 
> skirt it is meaningless for the actual passband.
> 

There is very little ripple in either the 5-pole or 8-pole filters (as can
be seen in the previous plots), so -6 dB is well beyond any ripple effect.

I'll write up a simple procedure later and post it under a more descriptive
Subject.  All you need to do this is a stable signal (like an XG1), the K3's
internal AFV/dBV meter and the VFO.  It's not necessary to use Spectrogram
and can actually be done more accurately using the internal K3's internal
capability.
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