K2 Mods for KPA100

[Jim Harris-4]

Hi,

Just starting on a KAP100 for my K2 SN 4787.  (BTW, in
my last email I think I quoted the wrong SN.)  First
thing out of the chute is an instruction sheet to
change five components and add another to the K2.
There is a note to be sure to re-align the 12m/10 BPF
after completing the mod.  Would it be helpful to
remeasure or recalibrate any other functions?  Looks
like the second part of the mod is for the VFO ALC.
Or, should I just presume this is low risk?

BTW,  Built and installed the DSPx yesterday.  Made a
great radio even better.  IMHO, better than my
IC-746pro with all of it's bells and whistles.  I hope
I can remember how to wade thru all the DSPx menu's
while actually operating.  Still can't believe the low
receiver noise.  Yep, it's the K2 receiver,  I've got
three HF antennas up and have the capability to do
extensive A-B testing.

Have a great day!

Jim, AB0UK


               
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[KK7P]

Hello Jim!

>   ...I hope
> I can remember how to wade thru all the DSPx menu's
> while actually operating.  

Once you have the unit set to your liking -- and the defaults may be
very close -- you can cycle through 4 filter selections using the AFIL
button on the K2.  Ad you can toggle the denoiser on and off, as well as
the notch on and off, using a two-button-press.  So, you may not need to
use the menus at all!

But if you do need to change things for your personal preferences, the
menus make it possible.

Enjoy!

Lyle KK7P

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[Don Wilhelm-3]

Jim,

Those components will not be needed on your K2 (or any other K2 above
SN3000) - it already has the components installed for KPA100 support.
Elecraft does provide those parts in support of those folks having an older
K2 and adding the KPA100.

73,
Don W3FPR

> -----Original Message-----
>
> Just starting on a KAP100 for my K2 SN 4787.  (BTW, in
> my last email I think I quoted the wrong SN.)  First
> thing out of the chute is an instruction sheet to
> change five components and add another to the K2.
> There is a note to be sure to re-align the 12m/10 BPF
> after completing the mod.  Would it be helpful to
> remeasure or recalibrate any other functions?  Looks
> like the second part of the mod is for the VFO ALC.
> Or, should I just presume this is low risk?
>
>

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[srife]

Lyle,
        I am not too savvy on this DSP stuff. The denoiser seems a bit
strong for SSB. When I turn it on it seems that it takes a pretty strong
signal for any intelligible audio to make it through. Is this a simple
adjustment in the menus to turn the denoiser gain(for lack of a better word)
down. I guess you can tell, and I have to admit, that I have not studied the
custom tailoring instructions yet. The denoiser works great for CW...man
does it work great! If I turn down the SSB denoiser does that affect the CW
denoiser?

Thanks,

Stan Rife
W5EWA
Houston, TX
K2 S/N 4216
 

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Lyle Johnson
Sent: Saturday, March 26, 2005 1:42 PM
To: Jim Harris
Cc: Elecraft
Subject: Re: [Elecraft] K2 Mods for KPA100

Hello Jim!

>   ...I hope
> I can remember how to wade thru all the DSPx menu's
> while actually operating.  

Once you have the unit set to your liking -- and the defaults may be
very close -- you can cycle through 4 filter selections using the AFIL
button on the K2.  Ad you can toggle the denoiser on and off, as well as
the notch on and off, using a two-button-press.  So, you may not need to
use the menus at all!

But if you do need to change things for your personal preferences, the
menus make it possible.

Enjoy!

Lyle KK7P

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[KK7P]

Hello Stan!

> I am not too savvy on this DSP stuff. The denoiser seems a bit
> strong for SSB. When I turn it on it seems that it takes a pretty strong
> signal for any intelligible audio to make it through. Is this a simple
> adjustment in the menus to turn the denoiser gain(for lack of a better word)
> down.

Yes, there are three parameters you can adjust: beta (aggressiveness),
decay (how quickly the unit backs off) and "length" (set from 1 through 4).

These are better explained in the manual than I can summarize here in an
email message.  Please read those sections of the manual and work
through the examples.

> I guess you can tell, and I have to admit, that I have not studied the
> custom tailoring instructions yet. The denoiser works great for CW...man
> does it work great! If I turn down the SSB denoiser does that affect the CW
> denoiser?

Yes, they share the same parameters.  You might try going to the DSP
menu and HOLD the STORE button to cycle through the 4 "length" settings.
  In the end, though, you'll probably have to play with the various
parameters to find the combination that works best for you.

73,

Lyle KK7P

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[Leigh L. Klotz Jr WA5ZNU]

Thank you for explaining that.  Is that because the DSP can't find out
the mode?  So you can optimize the DSP for CW or SSB?  Or am I
confused?
On Sat, 26 Mar 2005 3:52 pm, Lyle Johnson wrote:
> Yes, they share the same parameters.
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[KK7P]

>> Yes, they share the same parameters.
>
> Thank you for explaining that.  Is that because the DSP can't find out
> the mode?  So you can optimize the DSP for CW or SSB?  Or am I confused?

You are not confused -- at least not on this point :-)

The denoiser is common to both the CW and SSB audio paths.  Since it is
mostly tailored to your audio preferences, it remains as you set it for
both modes.  The primary difference you will discover in using it for
SSB or CW is that CW signals sound louder through the denoiser than
voice signals.  This is because of a factor we call "correlation" which
is how the DSP decides if a voltage is part of noise (random) or part of
a desired signal (CW or voice, less random).  Because CW is more highly
correlated (less random than voice), it passes through the denoiser more
easily.  This effect is compensated for in the Sn and Cn gain menus,
which would normally be set to make the apparent audio level the same
for moderately strong signals of both types.

The denoiser is most effective with CW when the filters are wide.  As
the filters get narrower and narrower, the denoiser is less and less
useful, in part because the filters "color" the noise and make it seem
more like a signal.  The extreme example of this is ringing.

Enjoy!

Lyle KK7P

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