K3 NR triggering

[Craig-89]

Hi Steve

I also  seem to get the impression that the selected NR setting is not exacty the same as the selected  level within in the menu versus turning the DSP  NR on and off without entering the menu,  if that makes sense.

What I am finding is  that 2-4 when applied from within the menu, does not sound like  2-4 when directly turning the NR on and off without entering the menu. It sounds different after you  go and  turn NR off and then on again. Maybe its just the latency in the DSP that I am noticing.

 Anyway new firmware, new learning curve, who  knows? Anyone else notice this?

I also seem to get the impression that the noise blanker is working much better, especially the DSP blanker,  which is great.

73
Craig
VK3HE




     
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[KK7P]

> I also  seem to get the impression that the selected NR setting is not exacty the same as the selected  level within in the menu versus turning the DSP  NR on and off without entering the menu,  if that makes sense.


The NR is an adaptive filter.  When you turn it off, it is completely
reset: all buffers are flushed and filter coefficients zeroed.

When you move from setting to setting with the NR adjust feature, the
buffers are not flushed nor are the coefficients reset.  Instead, the
new settings are applied to the current state of the filter.  So, it
takes from a few tens of milliseconds to perhaps a couple of seconds for
the filter to adapt to the new settings.

73,

Lyle KK7P


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[Steve Ellington]

Lyle:
Maybe a quick lesson on proper use of the NR filter would help us. Thinks
like....If F1-1 doesn't work, do we go to F1-2 or F2-1 or should we skip a
few F's. Should we turn NR off then back on every time we make a change?
Does changing NR settings while receiving a cw signal matter or should one
change settings with no signal?
I guess I got spoiled by the IC-7800's NR. With it, you just turn it on and
the noise disappeared.
Steve
N4LQ
[hidden email]
----- Original Message -----
From: "Lyle Johnson" <[hidden email]>
To: "Craig" <[hidden email]>
Cc: <[hidden email]>
Sent: Thursday, August 27, 2009 9:10 AM
Subject: Re: [Elecraft] K3 NR triggering

>> I also  seem to get the impression that the selected NR setting is not
>> exacty the same as the selected  level within in the menu versus turning
>> the DSP  NR on and off without entering the menu,  if that makes sense.
>
>
> The NR is an adaptive filter.  When you turn it off, it is completely
> reset: all buffers are flushed and filter coefficients zeroed.
>
> When you move from setting to setting with the NR adjust feature, the
> buffers are not flushed nor are the coefficients reset.  Instead, the
> new settings are applied to the current state of the filter.  So, it
> takes from a few tens of milliseconds to perhaps a couple of seconds for
> the filter to adapt to the new settings.
>
> 73,
>
> Lyle KK7P
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html 

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[KK7P]

> Thinks like....If F1-1 doesn't work, do we go to F1-2 or F2-1 or should
> we skip a few F's.

Depends on the noise, the signal, the levels and the nature of the
artifacts of NR you best tolerate.  F1-x builds sharper filters, while
F4-x typically has more attenuation...

> Should we turn NR off then back on every time we make
> a change?

It usually won't adapt any faster if you do.

> Does changing NR settings while receiving a cw signal matter
> or should one change settings with no signal?

Since you are trying to maximize the intelligibility of the signal, I'd
only adjust it if there is a signal.

I normally leave mine at F1-1 unless there is a good reason to change
it.  But that is for my antenna (3 element SteppIR), noise level
(rural), band (20m daytime), mode (SSB), AGC settings (default THR and
SLP) and typical signals (weak to moderate) I encounter here.

73,

Lyle KK7P

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[P.B. Christensen]

QST's Product Review of the Flex-3000 is available to ARRL members at:

http://www.arrl.org/members-only/prodrev/pdf/pr0910.pdf

It's an interesting exercise to drag the Key Measurement Summary next to the
K3 and Flex 5K models.  Wide and narrow blocking gain compression shows
about 10dB worse than the Flex 5K, and almost 30 dB worse than the K3.  The
following note in the Key section caught my eye:

"Blocking level exceeds the threshold of ADC clippng."

Paul, W9AC

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