[Elecraft] [K3] K3 NR

[Lu Romero]

Joe:

I listended with a Heil ProSet last night... I will check
the impedance, dont know it offhand.

True, a mismatch would add to the effect.

-lu-

----- Original Message Follows -----
From: "Joe Subich, W4TV" <lists at subich.com>
To: "'Lu Romero - W4LT'" <lromero at ij.net>,
<elecraft at mailman.qth.net>
Subject: RE: [Elecraft] [K3]  K3 NR
Date: Wed, 26 Aug 2009 22:19:23 -0400

>> I prefer the sound of the 3.25 version for ssb, its
>> cleaner  and somewhat less bright (flatter in response). 
>> I had to  tweak the RX EQ to add some bass in the 3.27
>> version or it  sounds "harsh" in my headsets (I dont use
>> speakers hardly  ever, btw). 
>
>What is the impedance of your headphones?  With anything
>less  than 100 Ohms or so, the stock 10 uF headphone
>coupling caps  cause a significant LF roll off -
>particularly with 8 Ohm cans. 
>
>73, 
>
>   ... Joe, W4TV 
> 
>
>
>
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Lu
>> Romero - W4LT
>> Sent: Wednesday, August 26, 2009 10:09 PM
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] [K3] K3 NR
>> 
>> 
>> 
>> Lyle:
>> 
>> Just played with the NR in both SSB and CW, on 80 and 40.
>> 
>> First, I can hear the change of the filters now without 
>> turning things on and off, as you mentioned it would
>> work.   The frequency response is decidedly less "flat"
>> (less bassy)  than the sound of 3.25.  For CW, the 3 and
>> 4 settings are  much more efficient, not so in SSB, where
>> the 1 and 2  settings are much cleaner sounding and
>> better copy.  I found  that with no antenna and with the
>> RF gain turned to 12  o'clock... Turn on the NR and all
>> receiver white noise mutes  and slowly ramps up.  That's
>> a recursive effect, I guess. 
>> I prefer the sound of the 3.25 version for ssb, its
>> cleaner  and somewhat less bright (flatter in response). 
>> I had to  tweak the RX EQ to add some bass in the 3.27
>> version or it  sounds "harsh" in my headsets (I dont use
>> speakers hardly  ever, btw).  Inteligibility is
>> marginally better with 3.27 on  ssb and quite a bit
>> better on CW, so you have drifted a bit  to the CW side
>> of the equation, but with a decent compromise for SSB. 
>> No more boingy peakyness in any mode, which is good, and
>> the  level while it still drops a bit, is better behaved.
>> 
>> Can I assume from some comments I have read here that the
>> NR  process is pre
>> EQ and AGC?  How exactly do the processes "stack" in the 
>> radio architecture?   
>> 
>> If NR is at the top of the stack, a decent "fix" might be
>> to  somehow gang these three processes using presets so
>> that they  can be set up ahead of time and recalled from
>> a memory button  by the user.
>> 
>> As an old brodcaster, we used to preset things in
>> Switchers  (vision mixers to UK readers) using a process
>> called E-MEM...  Which could recall preset parameters in
>> "salvos" to preset  multiple settings.  This might work
>> here. 
>> This would be handy in a contest environment where a
>> minimum  of tweaking and rapid adaptation to changing
>> conditions is  needed... You could play outside of a
>> contest and create the  settings then in the heat of
>> battle, recall them with a  single button push from a
>> "canned" setup.  It wouldnt be  perfect for any
>> environment, but it might mean the difference  between
>> working a mult and not working a mult.  And  multipliers,
>> after all, are.... :)   
>> As you said, every receiving environment is different,
>> but  some generalizations can be made and being able to
>> recall the  multiple settings would be a definite plus
>> feature of the radio. 
>> Thanks for letting us test these iterations. 
>> 
>> Lu Romero - W4LT
>> K3 # 3192 
>> 
>> 
>> Lyle Johnson wrote:
>> > 
>> >> ...For now I'll treat the parameter as an opaque
>> >> series of magic numbers.
>> > 
>> > The way the new beta NR works is:
>> > 
>> > Fx-y
>> > 
>> > x selects the length of the filter.
>> > 
>> > F1 = 121 taps, F2 = 91 taps, F3 = 61 taps, F4 = 31 taps
>> > 
>> > (The Beta 3.25 release used FIR filters of 61 taps.)
>> > 
>> > y selects values of Beta (gain), decay, and delay (how
>> > long the NR algorithm waits to process a signal)
>> > 
>> > (The Beta 3.5 release used the "x" parameter for these
>> > selections) 
>> > 73,
>> > 
>> > Lyle KK7P
>> > 
>> >
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>>
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