100 and 50 hz DSP filtering

[Chester Alderman]

I asked this question almost a year ago but my other brain cell forgot the
answer(s) I got, so in advance I apologize for the redundant question.

On my K3, I have switched between the FIR and the IIR filters when I have
the DSP filters set to either 100 hz or 50 hz, and can tell no improvement.
Why is it that there is a significant drop in signal level (on CW) when
either of those two filter widths are selected? And/or how can I fix the
signal level decrease?

Thanks and 73,

Tom - W4BQF


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[KK7P]

You are probably using Rx EQ and have your preferred
sidetone pitch peaked to something more than 0 dB.  RxEQ
is not available at these two narrow bandwidths.

Note:  It seems that many people believe that the Rx EQ is
an *additional* filter cascaded with the normal DSP
filter.  It is not.

In general, if you want to apply RxEQ shaping in CW mode,
I recommend that you set your preferred sidetone pitch to
0 dB and use cuts on either side, or for whatever shaping
you prefer, and not use any peaking above 0 dB.  That will
avoid this problem.

73,

Lyle KK7P

> Why is it that there is a significant drop in signal
>level (on CW) when
> either of those two filter widths are selected?
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[Lu Romero - W4LT]

This is why I monitor this reflector.  I did not know that
the filter was not cascaded; I assumed it was!

I have also experienced this "issue" as I do equalize on
receive... Now I know the reason why its not an "issue". I
will give it a try this evening and see if it solves the
"problem"  

How did I miss this in the manual's "Theory of Operation"
section? :)

-lu-W4LT-
K3 # 3192
------------------------

Message: 12
Date: Tue, 26 Jul 2011 15:10:07 -0700
From: "lyle johnson" <[hidden email]>
Subject: Re: [Elecraft] 100 and 50 hz DSP filtering
To: "Tommy Alderman" <[hidden email]>,
    <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="ISO-8859-1";
format="flowed"

You are probably using Rx EQ and have your preferred
sidetone pitch peaked to something more than 0 dB.  RxEQ
is not available at these two narrow bandwidths.

Note:  It seems that many people believe that the Rx EQ is
an *additional* filter cascaded with the normal DSP
filter.  It is not.

In general, if you want to apply RxEQ shaping in CW mode,
I recommend that you set your preferred sidetone pitch to
0 dB and use cuts on either side, or for whatever shaping
you prefer, and not use any peaking above 0 dB.  That will
avoid this problem.

73,

Lyle KK7P


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