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

[W7TEA]

Using this method I tweaked the Config menu filter offset adjustments for
my 500hz and 200hz filters.  It seemed to make a difference  centering 
the passband, especially on the narrower filter.  

Although my K3 was factory built, I have found that 
the REF CAL freq, S meter and now filter offsets all needed a bit of
tweaking.  

tnx and 73,  Gary W7TEA


Bill W4ZV wrote:
> 
> 
> 
> Ed Muns, W0YK wrote:
>> 
>> Another method, more laborious, but fairly accurate is to use the
>> Elecraft
>> XG1 or XG2 to inject a stable signal at the antenna port and deploy the
>> dbV
>> function in the K3 to measure the amplitude every 10 Hz or so.  Plot the
>> data manually or by entering into a spreadsheet that produces a graphic
>> of
>> the IF response.
>> 
> 
> You only need the two -6 dB points, which can be measured to a resolution
> of 1 Hz and 0.1 dB using the internal AFV/dBV function.  You should set
> AGC Off and ensure WIDTH (i.e. the DSP BW) is >> than the filter you are
> measuring...otherwise you're measuring the combination of XFIL plus DSP. 
> I do this by disabling all filters except the one under test and setting
> WIDTH >> XFIL BW.  Once you have the two -6 dB points, then you can figure
> how much offset to enter so these two points are equidistant about the
> center.
> 
> 73,  Bill
> 
> 

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