I'll be the third to chime in on how useful the spectrogram method of
aligning filters is. The first time around (without spectogram) I
noticed similar results as you did, then I did the spectrogram
alignment and it got *much* better, but it still wasn't right. Third
time, it got even better. I'll be doing it again this weekend I think,
it's somewhat of an art but it's also gratifying to see how much of a
change it really can make.
As Don said, you can do this anytime, no cause for concern at this point.
73,
Jeff N6GQ
On 3/16/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Nick,
I wholeheartedly second this. I followed the manual and noticed the same thing
you did. When I hooked up Spectrogram I could clearly see that the narrower
filters were off center. I adjusted while watching the Spectrogram screen and
things sound *much* better.
Craig AC6NN
-------------- Original message ----------------------
From: "Don Wilhelm" <[EMAIL PROTECTED]>
>
> Nick,
>
> Sometimes the filters (particularly the narrower ones) do not respond well
> to the initial numbers in the manual because the filter center may be
> shifted a bit due to the particular set of matched crystals supplied. I
> don't think you have a problem.
>
> There is a solution, and that is called 'Spectrogram', which will provide a
> visual display of the filter shape and positioning on a computer screen.
> Download the last freeware version (5.17) of Spectrogram from www.n0ss.net
> and look at the instructions for using it on Tom's website or the Builder's
> Resource page of the Elecraft website.
>
> You could let the filter alignemnt wait until you have the rest of the K2
> built and the KSB2 (if you added that) installed and then you can do a
> complete dial calibration and filter alignment. Instructions for doing that
> are on my website http://w3fpr.qrpradio.com
>
> 73,
> Don W3FPR
>
> > -----Original Message-----
>
> >
> > Thrilled to get my K2 working on 7 MHz receive but I seem to have
> > a problem with filter settings.
> > Everything has checked out according to the book - no problems at
> > all (even my home-wound coils seem to work!!)
> > I have set up the filters exactly according to pages 88 and 89.
> > On Filter 1 the rx sounds great - plenty of gain, clean signals.
> > On the other 3 filters it sounds like I am listening through a
> > dense fog - I can tell the bandwidth is far narrower than F1 but
> > signals are weak and it sounds as if the filters are overlapping
> > each other (if you know what I mean). I have checked settings
> > again and all look OK. Does anyone recognise this problem please?
> > I am reluctant to proceed until I have sorted it out.
> > 73 Nick G3RWF
> >
> --
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