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K3 new V3.25 NR not so good for CW week signal

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William Carver

K3 new V3.25 NR not so good for CW week signal

I've noticed in homebrew receivers as the bandwidth narrowed, shedding
noise and QRM I preferred the gain to go up, increaseing the in-passband
signal amplitude. I always attributed it to formative years with a
Heathkit Q multiplier. It may be an effect similar to AGC with
adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
preferred to have strong signals sound louder rather than perfectly
flat. Prolly a psycho-acoustic explanation (or maybe just get my head
examined?).

In firmware one could increase the audio gain by an adjustable amount as
the IF bandwidth was decreased, with an operator-settable scaling
number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
sounds good to me.

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AC7AC

Re: K3 new V3.25 NR not so good for CW week signal

CONTENTS DELETED

The author has deleted this message.

Brett Howard

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by William Carver

This is sorta already there if you have multiple roofing filters. You
can define the gain that is added when each filter kicks in.

On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:

> I've noticed in homebrew receivers as the bandwidth narrowed, shedding
> noise and QRM I preferred the gain to go up, increaseing the in-passband
> signal amplitude. I always attributed it to formative years with a
> Heathkit Q multiplier. It may be an effect similar to AGC with
> adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
> preferred to have strong signals sound louder rather than perfectly
> flat. Prolly a psycho-acoustic explanation (or maybe just get my head
> examined?).
>
> In firmware one could increase the audio gain by an adjustable amount as
> the IF bandwidth was decreased, with an operator-settable scaling
> number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
> by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
> sounds good to me.
>
>
>
> ______________________________________________________________
> 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

Merv Schweigert

Re: K3 new V3.25 NR not so good for CW week signal

Not really, if you read the recommendations for the filters you will
notice
that caution is warranted for setting the gain higher than recommended,
for IMD prevention if I remember correct. Kind of like the Inrad roofing
filters, in some cases the gain is set to high and causes more IMD than
without the filter.
Some Inrad roofers for the FT-1000D had too much gain and the radio
was worse with them installed than without. W8JI had some measurements
on those issues.
Merv KH7C

> This is sorta already there if you have multiple roofing filters. You
> can define the gain that is added when each filter kicks in.
>
>
> On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
>
>> I've noticed in homebrew receivers as the bandwidth narrowed, shedding
>> noise and QRM I preferred the gain to go up, increaseing the in-passband
>> signal amplitude. I always attributed it to formative years with a
>> Heathkit Q multiplier. It may be an effect similar to AGC with
>> adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
>> preferred to have strong signals sound louder rather than perfectly
>> flat. Prolly a psycho-acoustic explanation (or maybe just get my head
>> examined?).
>>
>> In firmware one could increase the audio gain by an adjustable amount as
>> the IF bandwidth was decreased, with an operator-settable scaling
>> number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
>> by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
>> sounds good to me.
>>
>>
>>
>> ______________________________________________________________
>> 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
>>
>
> ______________________________________________________________
> 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
>
>

Brett Howard

Re: K3 new V3.25 NR not so good for CW week signal

Not saying I'd do it. (and I'm not with the 8 filters I have in my
radio) but one can if thats what they wish to do.

~Brett

On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:

> Not really, if you read the recommendations for the filters you will
> notice
> that caution is warranted for setting the gain higher than
> recommended,
> for IMD prevention if I remember correct. Kind of like the Inrad
> roofing
> filters, in some cases the gain is set to high and causes more IMD
> than
> without the filter.
> Some Inrad roofers for the FT-1000D had too much gain and the radio
> was worse with them installed than without. W8JI had some
> measurements
> on those issues.
> Merv KH7C
> > This is sorta already there if you have multiple roofing filters. You
> > can define the gain that is added when each filter kicks in.
> >
> >
> > On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
> >
> > > I've noticed in homebrew receivers as the bandwidth narrowed, shedding
> > > noise and QRM I preferred the gain to go up, increaseing the in-passband
> > > signal amplitude. I always attributed it to formative years with a
> > > Heathkit Q multiplier. It may be an effect similar to AGC with
> > > adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
> > > preferred to have strong signals sound louder rather than perfectly
> > > flat. Prolly a psycho-acoustic explanation (or maybe just get my head
> > > examined?).
> > >
> > > In firmware one could increase the audio gain by an adjustable amount as
> > > the IF bandwidth was decreased, with an operator-settable scaling
> > > number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
> > > by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
> > > sounds good to me.
> > >
> > >
> > >
> > > ______________________________________________________________
> > > 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
> > >
> >
> > ______________________________________________________________
> > 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
> >
> >
>

dave.wilburn

Re: K3 new V3.25 NR not so good for CW week signal

What is the best way of determining the gain setting? Seem to recall an app for this.

David Wilburn
NM4M
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Brett Howard <[hidden email]>

Date: Sat, 15 Aug 2009 15:51:46
To: Merv Schweigert<[hidden email]>
Cc: <[hidden email]>
Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal

Not saying I'd do it. (and I'm not with the 8 filters I have in my
radio) but one can if thats what they wish to do.

~Brett

On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:

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Merv Schweigert

Re: K3 new V3.25 NR not so good for CW week signal

http://www.elecraft.com/K3/Roofing_Filters.htm

> What is the best way of determining the gain setting? Seem to recall an app for this.
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
> -----Original Message-----
> From: Brett Howard <[hidden email]>
>
> Date: Sat, 15 Aug 2009 15:51:46
> To: Merv Schweigert<[hidden email]>
> Cc: <[hidden email]>
> Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal
>
>
> Not saying I'd do it. (and I'm not with the 8 filters I have in my
> radio) but one can if thats what they wish to do.
>
> ~Brett
>
> On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:
>
>> Not really, if you read the recommendations for the filters you will
>> notice
>> that caution is warranted for setting the gain higher than
>> recommended,
>> for IMD prevention if I remember correct. Kind of like the Inrad
>> roofing
>> filters, in some cases the gain is set to high and causes more IMD
>> than
>> without the filter.
>> Some Inrad roofers for the FT-1000D had too much gain and the radio
>> was worse with them installed than without. W8JI had some
>> measurements
>> on those issues.
>> Merv KH7C
>>
>>> This is sorta already there if you have multiple roofing filters. You
>>> can define the gain that is added when each filter kicks in.
>>>
>>>
>>> On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
>>>
>>>
>>>> I've noticed in homebrew receivers as the bandwidth narrowed, shedding
>>>> noise and QRM I preferred the gain to go up, increaseing the in-passband
>>>> signal amplitude. I always attributed it to formative years with a
>>>> Heathkit Q multiplier. It may be an effect similar to AGC with
>>>> adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
>>>> preferred to have strong signals sound louder rather than perfectly
>>>> flat. Prolly a psycho-acoustic explanation (or maybe just get my head
>>>> examined?).
>>>>
>>>> In firmware one could increase the audio gain by an adjustable amount as
>>>> the IF bandwidth was decreased, with an operator-settable scaling
>>>> number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
>>>> by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
>>>> sounds good to me.
>>>>
>>>>
>>>>
>>>> ______________________________________________________________
>>>> 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
>>>>
>>>>
>>> ______________________________________________________________
>>> 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
>>>
>>>
>>>
>
> ______________________________________________________________
> 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
>

Brett Howard

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by dave.wilburn

You can pull this off by looking at the filter setup in the K3Config
utility or you can find it in the menu of the K3.

~Brett (KC7OTG)

On Sun, 2009-08-16 at 02:12 +0000, [hidden email] wrote:

> What is the best way of determining the gain setting? Seem to recall an app for this.
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
> -----Original Message-----
> From: Brett Howard <[hidden email]>
>
> Date: Sat, 15 Aug 2009 15:51:46
> To: Merv Schweigert<[hidden email]>
> Cc: <[hidden email]>
> Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal
>
>
> Not saying I'd do it. (and I'm not with the 8 filters I have in my
> radio) but one can if thats what they wish to do.
>
> ~Brett
>
> On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:
> > Not really, if you read the recommendations for the filters you will
> > notice
> > that caution is warranted for setting the gain higher than
> > recommended,
> > for IMD prevention if I remember correct. Kind of like the Inrad
> > roofing
> > filters, in some cases the gain is set to high and causes more IMD
> > than
> > without the filter.
> > Some Inrad roofers for the FT-1000D had too much gain and the radio
> > was worse with them installed than without. W8JI had some
> > measurements
> > on those issues.
> > Merv KH7C
> > > This is sorta already there if you have multiple roofing filters. You
> > > can define the gain that is added when each filter kicks in.
> > >
> > >
> > > On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
> > >
> > > > I've noticed in homebrew receivers as the bandwidth narrowed, shedding
> > > > noise and QRM I preferred the gain to go up, increaseing the in-passband
> > > > signal amplitude. I always attributed it to formative years with a
> > > > Heathkit Q multiplier. It may be an effect similar to AGC with
> > > > adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
> > > > preferred to have strong signals sound louder rather than perfectly
> > > > flat. Prolly a psycho-acoustic explanation (or maybe just get my head
> > > > examined?).
> > > >
> > > > In firmware one could increase the audio gain by an adjustable amount as
> > > > the IF bandwidth was decreased, with an operator-settable scaling
> > > > number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
> > > > by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
> > > > sounds good to me.
> > > >
> > > >
> > > >
> > > > ______________________________________________________________
> > > > 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
> > > >
> > >
> > > ______________________________________________________________
> > > 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
> > >
> > >
> >
>
> ______________________________________________________________
> 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

Merv Schweigert

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by dave.wilburn

Sorry dont think that link had the info you wanted, lost the note I had
from Aptos talking about setting the gain of the filters, may have been
in the archives.
Merv KH7C

Merv Schweigert

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by dave.wilburn

[hidden email] wrote:
> What is the best way of determining the gain setting? Seem to recall an app for this.
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
>
Perhaps this is what you were looking for Dave,

[Elecraft] On K3 crystal filter gain compensation (FLx GN)

wayne burdick
Mon, 15 Jun 2009 12:26:43 -0700

Lately there has been some discussion about how much gain to add when
compensating for loss in the K3's individual crystal filters. The
general guideline is "as little as possible." I'd suggest starting with
0 and working up to as high as a few dB only if it seems necessary.

Narrow bandwidths themselves create a psychoacoustic "gain" effect, so
you don't really have to make up for the entire loss relative to wide
filters. Also, excessive gain can in extreme cases worsen the
performance of DSP signal processing, such as noise reduction (NR).
Finally, AGC tends to flatten signal amplitudes in general, further
reducing the need for per-filter compensation.

While I'm on this topic, I'd also like to suggest using a minimum of
both RX and TX EQ. The '0' levels were carefully determined
empirically, and in most cases the optimal values will be well below
the maximum range provided. Unless you have an aural sensitivity issue
in some pitch range, or a serious mic deficiency, I'd stay between +/-
6 dB. As with filter gain settings, excessive values can result in
adverse interaction with the DSP.

And yes, there will be per-mode RX EQ in a future firmware revision.
Thanks for all the suggestions on this.

73,
Wayne
N6KR

______________________________________________________________
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
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dave.wilburn

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by Brett Howard

I understand where to set the values. I'm asking how to empirically determine the value to use?

David Wilburn
NM4M
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Brett Howard <[hidden email]>

Date: Sat, 15 Aug 2009 19:19:02
To: <[hidden email]>
Cc: <[hidden email]>; Merv Schweigert<[hidden email]>; <[hidden email]>
Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal

You can pull this off by looking at the filter setup in the K3Config
utility or you can find it in the menu of the K3.

~Brett (KC7OTG)

On Sun, 2009-08-16 at 02:12 +0000, [hidden email] wrote:

> What is the best way of determining the gain setting? Seem to recall an app for this.
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
> -----Original Message-----
> From: Brett Howard <[hidden email]>
>
> Date: Sat, 15 Aug 2009 15:51:46
> To: Merv Schweigert<[hidden email]>
> Cc: <[hidden email]>
> Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal
>
>
> Not saying I'd do it. (and I'm not with the 8 filters I have in my
> radio) but one can if thats what they wish to do.
>
> ~Brett
>
> On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:
> > Not really, if you read the recommendations for the filters you will
> > notice
> > that caution is warranted for setting the gain higher than
> > recommended,
> > for IMD prevention if I remember correct. Kind of like the Inrad
> > roofing
> > filters, in some cases the gain is set to high and causes more IMD
> > than
> > without the filter.
> > Some Inrad roofers for the FT-1000D had too much gain and the radio
> > was worse with them installed than without. W8JI had some
> > measurements
> > on those issues.
> > Merv KH7C
> > > This is sorta already there if you have multiple roofing filters. You
> > > can define the gain that is added when each filter kicks in.
> > >
> > >
> > > On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
> > >
> > > > I've noticed in homebrew receivers as the bandwidth narrowed, shedding
> > > > noise and QRM I preferred the gain to go up, increaseing the in-passband
> > > > signal amplitude. I always attributed it to formative years with a
> > > > Heathkit Q multiplier. It may be an effect similar to AGC with
> > > > adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
> > > > preferred to have strong signals sound louder rather than perfectly
> > > > flat. Prolly a psycho-acoustic explanation (or maybe just get my head
> > > > examined?).
> > > >
> > > > In firmware one could increase the audio gain by an adjustable amount as
> > > > the IF bandwidth was decreased, with an operator-settable scaling
> > > > number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
> > > > by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
> > > > sounds good to me.
> > > >
> > > >
> > > >
> > > > ______________________________________________________________
> > > > 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
> > > >
> > >
> > > ______________________________________________________________
> > > 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
> > >
> > >
> >
>
> ______________________________________________________________
> 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

dave.wilburn

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by Merv Schweigert

Tnx

David Wilburn
NM4M
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Merv Schweigert <[hidden email]>

Date: Sat, 15 Aug 2009 16:29:47
To: <[hidden email]>
Cc: Brett Howard<[hidden email]>; <[hidden email]>; <[hidden email]>
Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal

[hidden email] wrote:
> What is the best way of determining the gain setting? Seem to recall an app for this.
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
>
Perhaps this is what you were looking for Dave,

[Elecraft] On K3 crystal filter gain compensation (FLx GN)

wayne burdick
Mon, 15 Jun 2009 12:26:43 -0700

Lately there has been some discussion about how much gain to add when
compensating for loss in the K3's individual crystal filters. The
general guideline is "as little as possible." I'd suggest starting with
0 and working up to as high as a few dB only if it seems necessary.

Narrow bandwidths themselves create a psychoacoustic "gain" effect, so
you don't really have to make up for the entire loss relative to wide
filters. Also, excessive gain can in extreme cases worsen the
performance of DSP signal processing, such as noise reduction (NR).
Finally, AGC tends to flatten signal amplitudes in general, further
reducing the need for per-filter compensation.

While I'm on this topic, I'd also like to suggest using a minimum of
both RX and TX EQ. The '0' levels were carefully determined
empirically, and in most cases the optimal values will be well below
the maximum range provided. Unless you have an aural sensitivity issue
in some pitch range, or a serious mic deficiency, I'd stay between +/-
6 dB. As with filter gain settings, excessive values can result in
adverse interaction with the DSP.

And yes, there will be per-mode RX EQ in a future firmware revision.
Thanks for all the suggestions on this.

73,
Wayne
N6KR

______________________________________________________________
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

Brett Howard

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by dave.wilburn

Well you can follow the convention that is mentioned I believe in the
manual and use the values outlined there. Or find a steady signal on
the air (or connect a signal generator) and use the AFV feature to
determine the level and detect the reduction in signal level as you
adjust through the filters and then you'll know how many dB delta you
have between filters.

~Brett

PS: The real answer to this question is to put in as little gain as it
takes to make you happy and no more. The less you can use the better.

On Sun, 2009-08-16 at 02:45 +0000, [hidden email] wrote:

> I understand where to set the values. I'm asking how to empirically determine the value to use?
>
> David Wilburn
> NM4M
> Sent from my Verizon Wireless BlackBerry
>
> -----Original Message-----
> From: Brett Howard <[hidden email]>
>
> Date: Sat, 15 Aug 2009 19:19:02
> To: <[hidden email]>
> Cc: <[hidden email]>; Merv Schweigert<[hidden email]>; <[hidden email]>
> Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal
>
>
> You can pull this off by looking at the filter setup in the K3Config
> utility or you can find it in the menu of the K3.
>
> ~Brett (KC7OTG)
>
> On Sun, 2009-08-16 at 02:12 +0000, [hidden email] wrote:
> > What is the best way of determining the gain setting? Seem to recall an app for this.
> >
> > David Wilburn
> > NM4M
> > Sent from my Verizon Wireless BlackBerry
> >
> > -----Original Message-----
> > From: Brett Howard <[hidden email]>
> >
> > Date: Sat, 15 Aug 2009 15:51:46
> > To: Merv Schweigert<[hidden email]>
> > Cc: <[hidden email]>
> > Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal
> >
> >
> > Not saying I'd do it. (and I'm not with the 8 filters I have in my
> > radio) but one can if thats what they wish to do.
> >
> > ~Brett
> >
> > On Sat, 2009-08-15 at 12:42 -1000, Merv Schweigert wrote:
> > > Not really, if you read the recommendations for the filters you will
> > > notice
> > > that caution is warranted for setting the gain higher than
> > > recommended,
> > > for IMD prevention if I remember correct. Kind of like the Inrad
> > > roofing
> > > filters, in some cases the gain is set to high and causes more IMD
> > > than
> > > without the filter.
> > > Some Inrad roofers for the FT-1000D had too much gain and the radio
> > > was worse with them installed than without. W8JI had some
> > > measurements
> > > on those issues.
> > > Merv KH7C
> > > > This is sorta already there if you have multiple roofing filters. You
> > > > can define the gain that is added when each filter kicks in.
> > > >
> > > >
> > > > On Sat, 2009-08-15 at 13:50 -0600, William Carver wrote:
> > > >
> > > > > I've noticed in homebrew receivers as the bandwidth narrowed, shedding
> > > > > noise and QRM I preferred the gain to go up, increaseing the in-passband
> > > > > signal amplitude. I always attributed it to formative years with a
> > > > > Heathkit Q multiplier. It may be an effect similar to AGC with
> > > > > adjustable flatness (May 1996 analog circuit, in DSP of K3). I found I
> > > > > preferred to have strong signals sound louder rather than perfectly
> > > > > flat. Prolly a psycho-acoustic explanation (or maybe just get my head
> > > > > examined?).
> > > > >
> > > > > In firmware one could increase the audio gain by an adjustable amount as
> > > > > the IF bandwidth was decreased, with an operator-settable scaling
> > > > > number. Say 0 = gain independent of bandwidth, to 100 = gain multiplied
> > > > > by K * (2800/DSP bandwidth). Very similar to the AGC rise scaling. That
> > > > > sounds good to me.
> > > > >
> > > > >
> > > > >
> > > > > ______________________________________________________________
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> > > > >
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> > > >
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> >
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dave.wilburn

Re: K3 new V3.25 NR not so good for CW week signal

Sounds good. Tnx

David Wilburn
NM4M
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Brett Howard <[hidden email]>

Date: Sat, 15 Aug 2009 20:21:22
To: <[hidden email]>
Cc: <[hidden email]>; Merv Schweigert<[hidden email]>; <[hidden email]>
Subject: Re: [Elecraft] K3 new V3.25 NR not so good for CW week signal

Well you can follow the convention that is mentioned I believe in the
manual and use the values outlined there. Or find a steady signal on
the air (or connect a signal generator) and use the AFV feature to
determine the level and detect the reduction in signal level as you
adjust through the filters and then you'll know how many dB delta you
have between filters.

~Brett

PS: The real answer to this question is to put in as little gain as it
takes to make you happy and no more. The less you can use the better.

On Sun, 2009-08-16 at 02:45 +0000, [hidden email] wrote:

drewko

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by AC7AC

I haven't played with the new NR enough yet but so far I haven't heard
any weak CW signals that were lost due to turning on the NR. As long
as the signal is still there and the S/N is better I don't mind if the
overall volume seems to decrease a little when NR is turned on. The
new NR sounds better to me than the old version, but I mostly use a
pretty wide filter setting for CW so haven't really tried it with a
very narrow filter and weak signal.

One small modification I would like is that when AGC is off and NR is
turned on, instead of flashing "N/A" on the display, the NR should
simply activate the AGC to the last used setting (Fast or Slow). This
is a minor irritation to those of us who frequently jump between
AGC-Off and AGC-On: you push NR; it flashes "N/A"; then you have to
push AGC and then NR again. NR should just turn on AGC as necessary.
(I don't really care whether or not AGC then remains on when NR is
subsequently turned off.)

73,
Drew
AF2Z

On Sat, 15 Aug 2009 13:21:19 -0700, Ron AC7AC wrote:

>Not just "Q-multipliers" but go back another generation to the regenerative
>receiver (or, more properly put, "regenerative detector"). Same thing. As
>you narrow the selectivity by adjusting the regeneration closer to the
>"critical point", the gain also increases, just as with a "Q-multiplier".
>
>I've gotten used to turning up the gain as I narrowed the selectivity on my
>post-regenerative Homebrew receivers so I didn't miss it on the K3.
>
>Ron AC7AC
>

n0tt1

Re: K3 new V3.25 NR not so good for CW week signal

In reply to this post by William Carver

> There is another group of people who appreciate a "peaking function"
for
CW. That group is those of use who remember using a Q-multiplier.

YES! I still have my old QF-1 in the store room....sure do miss the
"peak" function for weak signal CW.

In my view, it would be a definite "plus" to have a true, tunable,
peaking function on the K3!! Electraft, please DO move that feature to
the front burner!

Charlie, N0TT

It
had both a peak and null position and worked at the IF frequency. The
peak function was super for CW.

73 de Brian/K3KO
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