http://elecraft.85.s1.nabble.com/K3-Filter-Ring-with-Noise-tp3410069p3413904.html
> Normally I would agree with all these suggestions that help us hear CW under
> noisy conditions however I'm convinced that there is simply nothing there to
> hear. Let's say we are listening to a weak CW signal on a noisy band and the
> station sends the word T H E. What I hear is T S E because just at the wrong
> instant, the noise "blipped the dit". (new techy term). I'm not talking
> about huge QRN peaks of S9+30 or anything....Just a bit of atmospheric noise
> that's producing some S meter fluctuation and just enough noise to be
> annoying to listen to through a narrow CW filter but almost soothing when
> heard through a wide SSB filter.
> Listening to the same noise on the Jupiter is much less grating to the ears
> even when using the 150Hz filter setting. BTW: Edwin, who originally posted
> this question, tells me that his friend also has a Jupiter and although the
> receiver isn't quiet as good, it handles that type of noise aspect better.
> What's the deal with Jupiters? You can't even turn the AGC off!
> Typically I blame AGC for such things but I can turn AGC off and still get
> that blipping effect. The worst receiver I ever saw for this phenomena was
> the TS-570. That thing would blip out entire letters as if it were punching
> holes in the transmitted text. Nice little rig but not for copying CW in
> noise!
> I believe I'll play around with some audio software and try to see what I'm
> hearing or what I'm not hearing. It could be some kind of mental weakness!
>
> Steve
> N4LQ
>
[hidden email]
> ----- Original Message -----
> From: "Brett Howard" <
[hidden email]>
> To: <
[hidden email]>
> Cc: "'Steve Ellington'" <
[hidden email]>; "'Edwin Johnson'"
> <
[hidden email]>; <
[hidden email]>
> Sent: Sunday, August 09, 2009 1:35 AM
> Subject: Re: [Elecraft] K3 Filter Ring with Noise?
>
>
> > I'd never had a rig capable of going lower than 500Hz till I got the K3
> > and really found myself quite annoyed at times when the noise was high
> > and I really necked the filter down. Its taken me time to figure all
> > these things out but Joe really has some great tips here and has done an
> > excellent job explaining why these things work. I also find that use of
> > a lower FC makes the noise sit a little better with me as the noise is
> > more subdued and not as piercing.
> >
> > One thing to try is to turn the bandwidth down to around 200Hz and find
> > a quiet spot on the band then adjust your pitch up and down and listen
> > to the band noise in a few places to see what you prefer based on the
> > 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
> > an interesting thought but based on the whole logarithmic scaling stuff
> > it does make sense.
> >
> > I find the dualPB filter is nice but I kinda wish I could adjust the
> > 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
> > be something I'd be sticking on a PF button and I'd then use the dualPB
> > more often.
> >
> > ~Brett
> >
> > On Sat, 2009-08-08 at 23:42 -0400, Joe Subich, W4TV wrote:
> >>
> >> > 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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