http://elecraft.85.s1.nabble.com/K3-Filter-Ring-with-Noise-tp3410069p3412561.html
Normally I would agree with all these suggestions that help us hear CW under
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
even when using the 150Hz filter setting. BTW: Edwin, who originally posted
receiver isn't quiet as good, it handles that type of noise aspect better.
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
hearing or what I'm not hearing. It could be some kind of mental weakness!
> 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>> > > ______________________________________________________________
>> > > Elecraft mailing list
>> > > Home:
http://mailman.qth.net/mailman/listinfo/elecraft>> > > Help:
http://mailman.qth.net/mmfaq.htm>> > > Post: mailto:
[hidden email]
>> > >
>> > > This list hosted by:
http://www.qsl.net>> > > Please help support this email list:
http://www.qsl.net/donate.html>> >
>> > ______________________________________________________________
>> > Elecraft mailing list
>> > Home:
http://mailman.qth.net/mailman/listinfo/elecraft>> > Help:
http://mailman.qth.net/mmfaq.htm>> > Post: mailto:
[hidden email]
>> >
>> > This list hosted by:
http://www.qsl.net>> > Please help support this email list:
http://www.qsl.net/donate.html>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home:
http://mailman.qth.net/mailman/listinfo/elecraft>> Help:
http://mailman.qth.net/mmfaq.htm>> Post: mailto:
[hidden email]
>>
>> This list hosted by:
http://www.qsl.net>> Please help support this email list:
http://www.qsl.net/donate.html>