K2 filter pix

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K2 filter pix

john-477
I'm looking at a couple of ideas regarding the difficulty Im having in
getting my K2 to transmit where I hear (and getting the filters to line
up correctly!).

Here's a link the the filter performance pictures. Note that bandwidth seems
narrower than setting (maybe) and there's some odd dips in the response.

http://www.old-radios.com/K2filter.html

SN is 2597, w/most all updates applied. I did not build this rig and it's
always behaved this way (at least as long as I've owned it)

Comments appreciated!
John K5MO






t 04:01 AM 10/22/04 -0400, you wrote:

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Re: K2 filter pix

Mike S-8
This statement is the key: "sidetone was at 420 hz."

AFAIK, all of the filter alignment documentation assumes you've got the sidetone set to the default 600 Hz. If you want a 420 Hz sidetone, you need to set the marker in Spectrogram to 420 Hz, and align the filters so they're centered on that! Note that all your filters appear shifted about (600-420=) 180 Hz. The K2 firmware ends up adjusting VFO/BFO frequencies for CW mode based on the sidetone setting.

The accuracy of your transmission frequency will be dependent upon how closely you tune the received CW to 420 Hz audio (or more correctly, to the frequency at which the sidetone is set).


At 07:04 AM 10/24/2004, john wrote...
>Here's a link the the filter performance pictures. Note that bandwidth seems
>narrower than setting (maybe) and there's some odd dips in the response.
>
>http://www.old-radios.com/K2filter.html

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Re: K2 filter pix

Tom Hammond-3
Mike:

GREAT CATCH!!!

I have NO CLUE why I didn't latch on to that when he and I originally
corresponded.

He still seems to have some unusual peaks/dips, but they may be related to
the fact that he seems to be driving the input to Spectrogram (and his
sound card) a bit hard. He and I are still (I think) corresponding on this.

73,

Tom   N0SS

At 06:49 AM 10/24/04, Mike S wrote:

>This statement is the key: "sidetone was at 420 hz."
>
>AFAIK, all of the filter alignment documentation assumes you've got the
>sidetone set to the default 600 Hz. If you want a 420 Hz sidetone, you
>need to set the marker in Spectrogram to 420 Hz, and align the filters so
>they're centered on that! Note that all your filters appear shifted about
>(600-420=) 180 Hz. The K2 firmware ends up adjusting VFO/BFO frequencies
>for CW mode based on the sidetone setting.
>
>The accuracy of your transmission frequency will be dependent upon how
>closely you tune the received CW to 420 Hz audio (or more correctly, to
>the frequency at which the sidetone is set).
>
>
>At 07:04 AM 10/24/2004, john wrote...
> >Here's a link the the filter performance pictures. Note that bandwidth seems
> >narrower than setting (maybe) and there's some odd dips in the response.
> >
> >http://www.old-radios.com/K2filter.html
>
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