DSP Filter?

[Jimmy Lee-4]

When using Spectrogram to align the K2 filters do I need to set the DSP
filter to filter 1 or turn it off?
Jimmy, AE4DT

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[Don Wilhelm-2]

Jimmy,

For aligning the CW filters, it is adequate to just turn the DSP off, but
when aligning the SSB filters - particularly if one has widened the bandpass
to 2.2 or 2.5 ala the KI6WX mods, I prefer to remove the DSP completely and
put the 2 jumpers in place to restore the audio path.  The DSP has the low
pass filter in place all the time and will cut off the high frequency end of
the Spectrogram display with these wider filters.

If you look only for the low frequency corner of the bandpass, you can
likely get away with leaving the KDSP2 installed, but if this is your first
time through the Spectrgram routine, I advise you to temporarily remove it.

BTW, the same caution applies if one has the KAF2 installed too - it also
has a low pass filter.

73,
Don W3FPR

"Life is what happens when you are making other plans"
(John Lennon wrote it in a book, Mike Cross used it in a song - I don't know
who was first)

----- Original Message -----

> When using Spectrogram to align the K2 filters do I need to set the DSP
> filter to filter 1 or turn it off?
> Jimmy, AE4DT
>


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[Vic K2VCO]

Don Wilhelm wrote:

> The DSP has the low
> pass filter in place all the time and will cut off the high frequency end of
> the Spectrogram display with these wider filters.

I don't think this is true, Don.  The default filter 1 is a LP filter,
but turning off the DSP disables it.  The KAF2, on the other hand, DOES
have a hard-wired LP filter which you need to turn off with the slide
switch on the KAF2 board (or remove the board, as you suggest) when
aligning SSB filters.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

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[Jim Brown-9]

On Wed, 09 Jun 2004 12:50:46 -0700, Vic Rosenthal wrote:

>I don't think this is true, Don.  The default filter 1 is a LP filter,
>but turning off the DSP disables it.  

You're correct, Vic. That is, you DO need to turn off the DSP (in the DSP
setup menu) to disable the filters, both for SSB and CW, and you do NOT have
to remove the DSP to disable them.

On the other hand, once I have aligned the filters, I like to turn the DSP
filters back on and look at the combined response of the crystal filters and
the DSP filters when setting the DSP filters.

Jim Brown  K9YC

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[Don Wilhelm-2]

Folks, I guess I just started removing the KAF2 for filter aligment when I
first had to deal with it - then I just continued doing the same 'safe'
thing with the DSP2.  Since I don't use the KDSP2 on a regular basis, I will
bow to the advice better experts.
73,
Don W3FPR

"Life is what happens when you are making other plans"
(John Lennon wrote it in a book, Mike Cross used it in a song - I don't know
who was first)

----- Original Message -----
From: "Vic Rosenthal" <[hidden email]>
To: "Don Wilhelm" <[hidden email]>; "Elecraft" <[hidden email]>
Sent: Wednesday, June 09, 2004 3:50 PM
Subject: Re: [Elecraft] DSP Filter?


> Don Wilhelm wrote:
>
> > The DSP has the low
> > pass filter in place all the time and will cut off the high frequency
end of

> > the Spectrogram display with these wider filters.
>
> I don't think this is true, Don.  The default filter 1 is a LP filter,
> but turning off the DSP disables it.  The KAF2, on the other hand, DOES
> have a hard-wired LP filter which you need to turn off with the slide
> switch on the KAF2 board (or remove the board, as you suggest) when
> aligning SSB filters.
>
> --
> 73,
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco
>
>
>

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[Mike Harris-9]

G'day,

| Folks, I guess I just started removing the KAF2 for filter aligment when
I
| first had to deal with it

Unnecessary 'cos there is a slide switch on the KAF2 just for that
purpose, to bypass it.  If the KPA100 lid is fitted, the switch can be
conveniently used just by removing the top panel just in front of the
heatsink.

Regards,

Mike VP8NO
#1400


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