http://elecraft.85.s1.nabble.com/K3-Filter-Ring-with-Noise-tp3410069p3411652.html
and I really necked the filter down. Its taken me time to figure all
excellent job explaining why these things work. I also find that use of
more subdued and not as piercing.
noise rather than the pitch. Then see if you can live w/ that pitch.
I liked Joe's comment about it being spaced over more bandwidth. Thats
size of my focus filter as well as the outer skirts. I'd even be ok if
it was just a menu setting for the size of my focus filter. That would
>
> > You did a wonderful job explaining exactly what I've noticed.
> > To me, it seems as if the noise mixes or blends with the cw
> > and at times blips out cw characters. This only happens when
> > signals are weak and the band is noisy.
>
> What you are describing is not true filter 'ringing' but the
> effect of band limited noise. Even though the noise is fairly
> "random" it is confined in a narrow range and is close to the
> desired signal.
>
> Keeping the filter wider may be somewhat counterintuitive in
> noisy conditions but it helps in a couple ways ... first it
> spreads the noise power out and allows the desired signal to
> appear somewhat stronger than the "random" noise. Second if
> you use a lower center frequency the noise is spread over a
> wider percentage bandwidth and a larger portion of the noise
> is 'far enough' away from the desired signal to allow the
> ear-brain DSP system to work more effectively.
>
> > I've tried all the EQ settings, NR (which helps) and AGC
> > settings to no avail. I don't consider this "ringing" since
> > that's not what I'm hearing.
>
> Try a lower FC and slightly wider filters. Also give the
> Dual PB filter a try.
>
> 73,
>
> ... Joe, W4TV
>
>
>
> > -----Original Message-----
> > From:
[hidden email]
> > [mailto:
[hidden email]] On Behalf Of Steve Ellington
> > Sent: Saturday, August 08, 2009 9:32 PM
> > To: Edwin Johnson;
[hidden email]
> > Subject: Re: [Elecraft] K3 Filter Ring with Noise?
> >
> >
> > Edwin
> > You did a wonderful job explaining exactly what I've noticed.
> > To me, it
> > seems as if the noise mixes or blends with the cw and at
> > times blips out cw
> > characters. This only happens when signals are weak and the
> > band is noisy. I
> > recently came across an older TenTec Jupiter which has very
> > wide skirts and
> > virtually no roofing filter (15kHz). The same noise has no
> > effect on it. I
> > have done dozens of A/B test and the Jupiter always comes out
> > the winner
> > until someone with an S9+30 signal gets within the roofing filter's
> > bandpass, like 6kHz away, and pumps the hardware AGC
> > violently. Then it's
> > all over and I either switch back to the K3 and suffer poor
> > copy or just
> > QRT.
> > I've tried all the EQ settings, NR (which helps) and AGC
> > settings to no
> > avail. I don't consider this "ringing" since that's not what
> > I'm hearing.
> >
> > Steve
> > N4LQ
> >
[hidden email]
> > ----- Original Message -----
> > From: "Edwin Johnson" <
[hidden email]>
> > To: <
[hidden email]>
> > Sent: Saturday, August 08, 2009 3:34 PM
> > Subject: [Elecraft] K3 Filter Ring with Noise?
> >
> >
> > > I've had my K3, which I assembled, about a month, outfitted with
> > > 13kHz,
> > > 6kHz,
> > > 2.8kHz, and 400Hz filters. Thus far I've been exceptionally
> > pleased with
> > > all
> > > aspects of the rig. I've read with interest the audio
> > discussions of this
> > > group. There is one area in which I'm not totally
> > satisfied, but this may
> > > be
> > > due, partially, with my expectations of the rig.
> > >
> > > When using CW on noisy bands, meaning the sort of
> > atmospheric noise we
> > > often
> > > are having now (NOT static crashes from storms), there
> > appears to be an
> > > audio
> > > product as the bandwidth is narrowed which is annoying to
> > my ears, which
> > > occurs both in speakers and phones. This is basically like
> > a ringing of
> > > the
> > > filters and especially evident as the passband is narrowed
> > to 50-150Hz.
> > > This
> > > phenomenon is not a problem in quiet conditions nor if the
> > station is
> > > especially strong, but can overpower a very weak station.
> > (I'm using a
> > > pitch
> > > of 600Hz for CW.)
> > >
> > > (I've tried eliminating the 400Hz filter to make certain
> > there isn't a
> > > problem there, and all is well with that filter, apparently.)
> > >
> > > I've been reducing RF gain and sometimes widening the
> > passband to help
> > > aleviate the problem, as well as using the NR. I've also
> > modified the
> > > RX equalizer from flat to settings of: #1=0, #2=3, #3=3,
> > #4=-1, #5=-4,
> > > #6=-5, #7=-8, #8=-10. Admittedly, part of these settings accomodate
> > > SSB to give, what I hear, as a very pleasant sound for that
> > mode. The
> > > primary ranges of this noise are affected mostly by filters
> > #4 and #5.
> > >
> > > If the RX equalizer settings remain flat, hence 0, the
> > sound is even
> > > more annoying. But remember this is really only in noisy
> > conditions,
> > > so my hypothesis is that the chaotic sounds in the noise
> > are mixing to
> > > produce what sounds like a ringing of the filters. (So not
> > necessarily
> > > the filters actually ringing, as we think of it.) But this makes
> > > working very weak signals very difficult without widening
> > the passband
> > > quite a bit.
> > >
> > > So, guess I would like to hear comments regarding this, as well as
> > > settings
> > > and techniques people use to combat this phenomenon.
> > >
> > > 73 ...Edwin, KD5ZLB
> > > ____________________________________________________________
> > > "Once you have flown, you will walk the earth with your eyes turned
> > > skyward, for there you have been, there you long to
> > return."-da Vinci
> > >
http://bellsouthpwp2.net/e/d/edwinljohnson> > > ______________________________________________________________
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