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

[Bill W4ZV]

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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