[TenTec] Re: FYI - key click thread on Ten-Tec reflector

Thu, 31 Jan 2002 22:47:49 -0500

I'm really enjoying this thread. Paul, I was searching for click info just
yesterday and came across that W9CF page. I must admit, it's way over my
head. I can't even tell what his findings are. Maybe you can give us a
condensed version.
Now for this question of ...Is it a click or is it the filter...?? I can
testify that on some cw signals, even ones that are 30db over S9, I can tune
within 200hz of them, sit the 870's dsp for a 100hz bw and not hear a single
click. However on most signals a click will indeed be heard. I'm sure some
of it has to do with cw speed and faster code produces a wider bw etc.

Jerry talks about how cw sounds different with different filters. To me,
TenTec filters ladder filters do have a very distinct sound and aren't prone
to ring nearly as bad as the lattice filters used by everyone else. The
little 1340 QRP rig is the prime example. QRN is almost a non-factor. Static
just makes a soft, amost peacful, sound while the big rigs are roaring like
volcanoes! DSP doesn't help much in QRN either. The skirts are very steep
and band noise can get quiet anoying. The 1350 has a 4 pole ladder filter in
it's one IF amplifier. No, it's not all that selective but sure is peacful
to monitor!
Speaking of the Omni VI. That microchrip is most easily heard on another TT
rig with ladder filters. Wonder why? Do lattice filters and their ringing
tend to "Dechirp" it?
Steve Ellington
N4LQ
----- Original Message -----
From: "Paul Christensen" <paulc@mediaone.net>
To: "Steve Ellington" <n4lq@iglou.com>; "Carl Moreschi"
<n4py@earthlink.net>; <tentec@contesting.com>
Sent: Thursday, January 31, 2002 9:16 PM
Subject: Re: [TenTec] Re: FYI - key click thread on Ten-Tec reflector

> If you go to the Topband archives on contesting.com, there's been a very
> good discussion running recently concerning key clicks and as you mention
> Steve, the ability to hear what's always been there with DSP filtering.
> W8JI and W9CF have recently conducted some exhaustive research.  If you go
> the w8ji.com web site, you'll see quite a bit of information relating
> specifically to key clicks on the FT-1000MP.  W9CF has done some
incredible
> analysis on the effects.  Take a look at his site at the following
link....
>
> http://fermi.la.asu.edu/w9cf/articles/click/index.html
>
> And here's Tom's link....
>
> http://www.w8ji.com/Click
>
> -Paul, W9AC
>
>
>
> ----- Original Message -----
> From: "Steve Ellington" <n4lq@iglou.com>
> To: "Carl Moreschi" <n4py@earthlink.net>; <tentec@contesting.com>
> Sent: Thursday, January 31, 2002 20:47 PM
> Subject: Re: [TenTec] Re: FYI - key click thread on Ten-Tec reflector
>
>
> > I'm not sure about the 340 but certainly, DSP filtering has given us the
> > ability to really hear those clicks. This was mentioned in a QST review
of
> > one (IF) DSP reveiver. At first listen, they though the filtering was
> > somehow creating the clicks but later decided that the clicks were
> actually
> > there and had been overlooked while using standard crystal filtering. On
> the
> > TS-870, I can set the filter at 100 or 50hz, get in between signals and
> hear
> > nothing but clicks.
> > So what I'm asking is: Are rigs clicking more these days or are we just
> able
> > to hear them better with the brick wall dsp?
> > Steve Ellington
> > N4LQ
> > ----- Original Message -----
> > From: "Carl Moreschi" <n4py@earthlink.net>
> > To: <tentec@contesting.com>
> > Sent: Thursday, January 31, 2002 7:30 PM
> > Subject: Re: [TenTec] Re: FYI - key click thread on Ten-Tec reflector
> >
> >
> > > I would just like to add that last weekend I listened a lot to
> > > the 160 meter CW contest.  Using the Rx340 filters even down to 100
> > > hertz, I found key clicks were all over the band.  It was easy to find
> > > places where there were no CW tones, but impossible to find places
> > > where there were no key clicks.  It seems as though most rigs now
> > > generate excessive clicks.
> > >
> > > Carl Moreschi N4PY
> > > Franklinton, NC
> > > ----- Original Message -----
> > > From: "Tom Rauch" <w8ji@akorn.net>
> > > To: <tentec@contesting.com>
> > > Sent: Thursday, January 31, 2002 2:47 PM
> > > Subject: [TenTec] Re: FYI - key click thread on Ten-Tec reflector
> > >
> > >
> > > > > >From W9AC:
> > > > > "Correct to the extent that CW bandwidth may be minimized.  I
don't
> > > > > necessarily agree with Tom's view that the "correct" CW waveform
is
> > > > > one in which the transmitted bandwidth is minimized by extending
the
> > > > > rise and decay of the envelope and turning the wave edges into a
> > > > > sine-slope characteristic. The problem with Tom's approach is that
> in
> > > > > minimum signal conditions and at relatively high CW speeds, his
> > > > > preferred wave form becomes difficult read. In essence, the
> "correct"
> > > > > CW wave form is purely subjective.
> > > >
> > > > That is not true by any observation I have gathered in well over 50
> > > > tests when my signal was weak on 160 meters.
> > > >
> > > > I now use a waveshape that is similar to a sine rise and fall, and
no
> > > > one so far can tell any difference at all when I "square it" except
> > > > the people up or down a few kHz.
> > > >
> > > > I work just as much DX when my signal is marginal, and when I do
> > > > an A-B test no one so far can tell the difference unless I AM
> > > > strong.
> > > >
> > > > What proponents of wide bandwidth-wasting clicking CW signals
> > > > forget is that the ear and the receiver system up to your ear,
unlike
> > > > a power meter, does not measure or store "average power" or
> > > > accumulated power. Until the accumulated rise and fall time
> > > > approaches the width of a "dit", it makes no difference at all in
> > > > weak signal copy.
> > > >
> > > > We have to have some respect for other people on the bands. As
> > > > far as I am concerned, people can click and clack all they like as
> > > > long as they respect my space, and stay a few kHz away from all
> > > > other operators on the band...especially weak signals.
> > > >
> > > > > "My preference is for a fast leading edhe in the order of 1.5 mS,
> and
> > > > > a trailing decay in the order of 5-6 mS, much the same as is often
> > > > > shown in the older ARRL handbooks when grid-block keying is used.
> > > >
> > > > That will click, and occupy excessive and unnecessary bandwidth.
> > > > The closest possible sideband would be almost 700Hz away, no
> > > > matter what speed you are sending. Even if you used a filtered sine-
> > > > shaped envelope, your signal would be 1.5 kHz wide.  With a
> > > > normal single pole R/C filter, which gives the poorly filtered
> > > > waveshape the handbook calls "ideal", you would have garbage out
> > > > a few kHz each direction every time the envelope rose.  That
> > > > garbage would be there no matter if you sent one word per minute,
> > > > or a hundred words per minute.
> > > >
> > > > While you may "like hearing" an excessively-short clicking rise
> > > > time, it is poor engineering and wasteful of spectrum to transmit
> > > > that way on crowded bands. It is poor form to promote something
> > > > that will cause all CW signals to be well over 1.5kHz wide.
> > > >
> > > > > This produces a percussive CW note with a slight "bell-sound."
No,
> it
> > > > > is not as spectrally pure as what Tom suggests, but the note is
very
> > > > > distinctive and easy to copy.  A bit of extra bandwidth can
> sometimes
> > > > > be a good thing."
> > > >
> > > > I'm sure it is a "good thing" for some of us when we are dishing it
> > > > out. For one thing it ensures others can't stand operating within a
> > > > kHz or two of you. When we are on the receiving end of the
> > > > needless clicks, it isn't so wonderful!
> > > >
> > > > My goal is to have a click-less signal that occupies no more
> > > > bandwidth than necessary.
> > > >
> > > > There is no logical reason in the world for a CW signal to occupy
> > > > more than a few hundred Hz of bandwidth.
> > > > 73, Tom W8JI
> > > > W8JI@contesting.com
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