[Elecraft] K3 8 pole filter offsets

[Radio Amateur N5GE]

On Sat, 17 Oct 2009 12:37:31 +0100, Dave G4AON
<elecraft at astromag.co.uk> wrote:

>Since obtaining an 8 pole 250 Hz filter to compliment my 8 pole 400 Hz
>filter, I have been puzzled as to why the 400 Hz filter appeared to have
>more loss than the 250 Hz one (it should be the other way around).
>Talking with another K3 owner brought the possibility that the 400 Hz
>filter might need an offset, so I fed my signal generator into the K3
>and checked. Adjusting the offset brought up the signal by 1 S-Unit to
>match the reading from the 250 Hz filter, I set the offset in the middle
>of the two points where the meter dropped. The optimum setting for my
>filter is -0.07.
>
>I think this has been discussed here before (possibly by Tom, N0SS) but
>I couldn't find it during a search.
>
>My 400 Hz filter was supplied with my K3 in Nov 2007, the 250 Hz filter
>was new this year.
>
>73 Dave, G4AON
>K3/100 #80
[snip]

I found this to be true of my 400Hz and 250Hz filters also.  

If you also have a sub RX it will help get the two to be exactly
together by doing the same to net the filters in the SUB with main.

Tom, N5GE

n5ge at n5ge.com
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