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

Sun Aug 16 00:45:51 EDT 2009

Sounds good. Tnx

David Wilburn
NM4M 
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Brett Howard <brett at livecomputers.com>

Date: Sat, 15 Aug 2009 20:21:22 
To: <dave.wilburn at verizon.net>
Cc: <elecraft-bounces at mailman.qth.net>; Merv Schweigert<k9fd at flex.com>; <Elecraft at mailman.qth.net>
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, dave.wilburn at verizon.net 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 <brett at livecomputers.com>
> 
> Date: Sat, 15 Aug 2009 19:19:02 
> To: <dave.wilburn at verizon.net>
> Cc: <elecraft-bounces at mailman.qth.net>; Merv Schweigert<k9fd at flex.com>; <Elecraft at mailman.qth.net>
> 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, dave.wilburn at verizon.net 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 <brett at livecomputers.com>
> > 
> > Date: Sat, 15 Aug 2009 15:51:46 
> > To: Merv Schweigert<k9fd at flex.com>
> > Cc: <Elecraft at mailman.qth.net>
> > 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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