Re: [Elecraft] [K3] K3 NR

[Vic K2VCO]

Bill W4ZV wrote:

[about NR and SNR]

I've been watching this thread with interest. For a few years and several 
different 
radios, I've been repeating the same test:

1) Tune around with a bandwidth of about 400 Hz. Find a weak CW signal close to 
the noise 
which I can't copy 100%.

2) Try all the possible techniques to improve intelligibility, looking for the 
ones that 
improve the percentage of copy.

Here is what I've learned:

1) If there is a kind of noise that a NB will reduce, that helps.

2) If there is not too much noise, reducing the bandwidth further helps. I 
sometimes go 
down to 50 Hz. on the K3. But on a noisy band this makes it worse.

3) AFX doesn't matter one way or the other.

4) Dual-diversity reception (polarization diversity) *REALLY* helps. IMHO this 
is one of 
the K3's greatest features.

5) NR doesn't help with the weakest signals.

6) I can't decide what pitch is best. Usually I use around 500 Hz. but that's 
because I 
like the sound of it.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Re: [Elecraft] [K3] K3 NR

[Bill W4ZV]

Bill W4ZV wrote:
> 
> 
> 
> David Woolley (E.L) wrote:
>> 
>> The main source of published research on real time noise reduction of 
>> audible signals seems to be the hearing aid industry.  I just came 
>> across this article suggesting that hearing aid noise reduction 
>> strategies make people think that the noise is less sever, but don't 
>> actually make the signal any more intelligible.
>> 
>> Trends in Amplification, Volume 10, No. 2, June 2006: Acceptance of 
>> Background Noise, Mueller et al. 
>> 
>> 
> 
> That's an interesting article David!  It agrees with my feelings over the
> many years I've tried various types of noise reduction.  Sometimes I think
> we're fooled by the level changes introduced by NR, when in fact we could
> probably do as well simply by turning AF Gain down a little.  
> 
> A few years ago when NQ5T and I both had Orions, I challenged Grant to
> measure the actual S/N with NR on and off.  At narrow bandwidths, there
> was no difference in measured S/N.  Of course this was for CW where NR
> simply builds a narrow filter around a discrete signal.  
> 

This was for Orion II,  but for anyone interested, here's the summary by
Grant NQ5T:

http://lists.contesting.com/archives//html/TenTec/2006-03/msg01118.html

On March 25, 2006, NQ5T wrote:

[TenTec] Orion II NR Performance Measurements

I won't bore you with the setup here, but will be happy to provide details
to anyone who is interested.  Consistent results were obtained by two
independent methods: (1) graphical computation of SNNR, and (2) spectral
analysis software that directly computes an estimate of SNR.

The results are as follows (LCW, 1000Hz spot tone, NR=9)  

BW=3000Hz: SNNR improves by approx 1dB with NR=9.

BW=500Hz:  SNNR degrades by approx 2dB with NR=9.

There is improvement at 3 Khz bandwidth, but it's negligible.  At 500 Hz
(and anything below that as well) you're better off without NR at all.  The
distortion created by NR at any bandwidth in both CW tone and SSB voice is
very unpleasant compared to typical noise reduction products. 

Even without having a v1 Orion to compare with I'm basically moving from the
"uncertain" bench to the "put it back the way it was" bench.

Grant/NQ5T


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Re: [Elecraft] [K3] K3 NR

[Bill W4ZV]

David Woolley (E.L) wrote:
> 
> The main source of published research on real time noise reduction of 
> audible signals seems to be the hearing aid industry.  I just came 
> across this article suggesting that hearing aid noise reduction 
> strategies make people think that the noise is less sever, but don't 
> actually make the signal any more intelligible.
> 
> Trends in Amplification, Volume 10, No. 2, June 2006: Acceptance of 
> Background Noise, Mueller et al. 
> 
> 

That's an interesting article David!  It agrees with my feelings over the
many years I've tried various types of noise reduction.  Sometimes I think
we're fooled by the level changes introduced by NR, when in fact we could
probably do as well simply by turning AF Gain down a little.  

A few years ago when NQ5T and I both had Orions, I challenged Grant to
measure the actual S/N with NR on and off.  At narrow bandwidths, there was
no difference in measured S/N.  Of course this was for CW where NR simply
builds a narrow filter around a discrete signal.  

I believe a filter is a filter is a filter...whether crystal, DSP or NR. 
There is no magic.

73,  Bill

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Re: [Elecraft] [K3] K3 NR triggering

[Steve Ellington]

Thanks for the nice explanation Bill. It is effective but weird. Somone 
needs to make a movie.
Steve
N4LQ
n...@carolina.rr.com
- Original Message - 
From: "Bill W4ZV" 
To: 
Sent: Thursday, August 27, 2009 7:12 AM
Subject: Re: [Elecraft] [K3] K3 NR triggering


>
>
>
> Steve Ellington wrote:
>>
>> I just had a CW QSO on a noisy 80m. Here's what I noticed with NR set for
>> F1-3. BW set for 2.5 kHz.
>> QRN very loud! I pushed NR. Band goes almost totally silent. Calling CQ
>> with
>> the bug was like being in TX mode but I was using QSK as always.
>> Wow...Nice
>> and quiet. Then someone answered my CQ. On his very first DIT, the noise
>> level jumped up and stayed up throughout the entire QSO. It was quieter
>> than
>> no NR at all but why should it stay that way???
>>
>
> Remember that NR is an adaptive filter.  When you perturb it with a 
> coherent
> signal it rebuilds the filter around that signal.  F1 is the longest tap
> setting which means it has the greatest stored data stream and will take 
> the
> longest to respond when you add new data (i.e. a signal).  Once the new
> input to the filter (signal plus noise) is steady state, the filter will
> then stay in that state until the inputs change again (i.e. when the 
> signal
> goes away).
>
> 73,  Bill
> -- 
> View this message in context: 
> http://n2.nabble.com/K3-NR-triggering-tp3521099p3524344.html
> Sent from the [K3] mailing list archive at Nabble.com.
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Re: [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" 
To: "'Lu Romero - W4LT'" ,

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-boun...@mailman.qth.net 
>> [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lu
>> Romero - W4LT
>> Sent: Wednesday, August 26, 2009 10:09 PM
>> To: elecraft@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 B

Re: [Elecraft] [K3] K3 NR triggering

[Bill W4ZV]

Steve Ellington wrote:
> 
> I just had a CW QSO on a noisy 80m. Here's what I noticed with NR set for 
> F1-3. BW set for 2.5 kHz.
> QRN very loud! I pushed NR. Band goes almost totally silent. Calling CQ
> with 
> the bug was like being in TX mode but I was using QSK as always.
> Wow...Nice 
> and quiet. Then someone answered my CQ. On his very first DIT, the noise 
> level jumped up and stayed up throughout the entire QSO. It was quieter
> than 
> no NR at all but why should it stay that way???
> 

Remember that NR is an adaptive filter.  When you perturb it with a coherent
signal it rebuilds the filter around that signal.  F1 is the longest tap
setting which means it has the greatest stored data stream and will take the
longest to respond when you add new data (i.e. a signal).  Once the new
input to the filter (signal plus noise) is steady state, the filter will
then stay in that state until the inputs change again (i.e. when the signal
goes away).

73,  Bill
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Re: [Elecraft] [K3] K3 NR

[Joe Subich, W4TV]

> 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-boun...@mailman.qth.net 
> [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lu 
> Romero - W4LT
> Sent: Wednesday, August 26, 2009 10:09 PM
> To: elecraft@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
> > 
> > __
> > Elecraft mailing list
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> > Help: http://mailman.qth.net/mmfaq.htm
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> > 
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > 
> > 
> 
> -- 
> View this message in context: 
> http://n2.nabble.com/K3-NR-tp3515659p3520809.html
> Sent from the [K3] mailing list archive at Nabble.com. 
> 

Re: [Elecraft] [K3] K3 NR

[Lu Romero - W4LT]

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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Re: [Elecraft] [K3] K3 NR

[Bill W4ZV]

Brett Howard wrote:
> 
> As far as the shift you're mentioning are you talking about the fact
> that the FC star moves to the freq that you have pitch configured for?
>  The filter is still centered in the IF land but it looks like a shift
> because the K3 tells you about its filters in AF terms.
> 

No.  At low pitches, the MCU shifts the IF filter such that the lower side
is never lower than ~200 Hz.  If you're using a 500 Hz XFIL and PITCH 300,
the XFIL passband is actually 200-700 Hz...not 300 +/-250 (i.e. not 50-550
which would be centered).  Even though you see FC*.30 for the DSP filter,
the IF filter is actually offset.

73,  Bill

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Re: [Elecraft] [K3] K3 NR

[AB3EN]

I agree alsoWayne and the boys hit it just right for me. Great job. Very
noisy 40M today and the combination of the NB 3-3 and AFX pulled real
understandable voices out of junk. I will play with the setting for awhile
until I fine what is optimal for me but all in all it is just splitting
hairs at this point.

Dan



AD4C2009 wrote:
> 
> Ian,I am with you,it works outstanding now,I don't even lose the audio as
> other said,it drops a liitle bid but still is confortable to my ears but
> the noise is totally GONE ! About the low end roll-off on version 3.25 was
> at 30 Hz,now with 3.27 is at 60Hz,who needs to hear that low? besides do
> your speaker respond to 30Hz,besides does anyone on ESSB respond that low?
> so 60 Hz is ok with me.73 to all
>  
> AD4C
>  
> 
> 
> 
> 


-

Dan AB3EN
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Re: [Elecraft] [K3] K3 NR

[Paul Christensen]

> low based on my experience with the 930.  I still have my 930 and may have
> to drag it out to see what 50 Hz sounds like, but that sounds awfully low
> based on my previous experience.

Not too many rigs have the audio capabilities to produce a reasonably flat 
response to 100 Hz and below.  So, while the TS-930 may have had the ability 
to shift that low, it would be interesting to see if the audio path could 
produce the low offset.   I have re-designed the audio path of the TS-850 
(mods available on the KA0KA website) and TS-950 receivers, both of which 
required substantial invasive work to bring down below 100 Hz.

Paul, W9AC


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Re: [Elecraft] [K3] K3 NR

[Bill W4ZV]

P.B. Christensen wrote:
> Until I purchased 
> the '7800 back in 2005, the only other radio I've owned that would produce 
> ultra-low-pitch CW was the TS-870 but I never bothered trying low pitch CW 
> reception until I tried it with the Icom.
> 

The TS-930S had an infinitely variable PITCH control which went down to zero
(and maybe even beyond to negative IF since it was analog).  It
simultaneously adjusted sidetone, filter center and TX offset so you were
always zero beat if you matched the sidetone to the signal.  It was easy to
tune in a weak signal and then adjust PITCH for the optimum S/N for your
ears.  This is how I discovered my ears liked the 240-270 Hz range.  Orion
also allows setting PITCH as low as 200 Hz but I never used settings that
low based on my experience with the 930.  I still have my 930 and may have
to drag it out to see what 50 Hz sounds like, but that sounds awfully low
based on my previous experience.  

I still don't understand why the K3 limits us to 300 Hz PITCH when Orion
(which has a very similar block diagram) goes to 200 Hz.  Ten-Tec changed
their original lower limit of 300 Hz to 200 Hz within a month of my request
to lower it...and they also keep their crystal filters centered instead of
shifting them at lower PITCH settings (as the K3 does), so the radios
apparently have some differences that are not obvious to me.

73,  Bill

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Re: [Elecraft] [K3] K3 NR

[Laurent F6DEX]

I come back to 3.25 also ; was much better with 3.25. Here audio is much
lower with 3.27.

73, Laurent F6DEX
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[Elecraft] [K3] K3 NR on SSB

[Julius Fazekas n2wn]

The NR can do wonders... there were several QSOs I made that most likely
would not have been possible without it.

On the other hand, with a nearby LOUD station or splatter, it is very harsh
to listen to. This may just be a fact of life, but am interested in any
suggestions to improve it.

Turning the gain and volume waaay down helped some.

Some of the overdriven signals and splatter were downright ugly this weekend
on 160. There were several stations where it was virtually impossible to
copy anything within 3 Khz of their center frequency. I would have though
they were running AM they were so wide. (no this isn't a negative comment on
AM)

Still I was hearing stuff others weren't and that was way cool!

73,
Julius

-
Julius Fazekas
N2WN

Tennessee Contest Group
http://www.k4ro.net/tcg/index.html

Tennessee QSO Party
http://www.tnqp.org/

Elecraft K2/100 #4455
Elecraft K3/100 #366
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