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PA2AGA > HDDIG 03.07.00 23:53l 208 Lines 6903 Bytes #-9412 (0) @ EU
BID : HD_2000_178C
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Subj: HamDigitalDigest 2000/178C
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Sent: 000703/1811Z @:PI8HGL.#ZH1.NLD.EU #:57999 [Den Haag] FBB $:HD_2000_178C
From: PA2AGA@PI8HGL.#ZH1.NLD.EU
To : HDDIG@EU
Date: Mon, 03 Jul 00 19:07:53 MET
Message-Id: <hd_2000_178C>
From: pa2aga@pe1mvx.ampr.org
To: hd_broadcast@pa2aga.ampr.org
X-BBS-Msg-Type: B
>>
>> Im am now not active, but if I were to go on air again it would be using
>CW.
>>
>> Let us not flame each other but respect our differing interests.
>>
>> Graham formerly VK7ZO and VK1ZO
>>
>> Graham in Canberra Australia
>>
>>
>>
>> .
>>
>>
>>
>>
>
Gary Coffman KE4ZV | You make it |mail to ke4zv@bellsouth.net
534 Shannon Way | We break it |
Lawrenceville, GA | Guaranteed |
------------------------------
Date: Sun, 2 Jul 2000 17:37:49 -0400
From: "Bob Lewis" <aa4pb@erols.com>
Subject: CW versus hi speed digital etc.
> Try high speed CW on HF with a keyboard program and high
> speed CW reader program, it often works as well as, or better
> than, at the same speeds, more modern digital modes on the
> HF channel.
>
You're dreaming! I've worked machine CW at 80 to 90 WPM on HF and it
worked pretty well *with an excellent signal to noise ratio*. It falls
apart pretty quickly when the SNR drops - long before any of the
modern digital modes including plain old RTTY.
------------------------------
Date: Sun, 2 Jul 2000 17:35:52 -0500
From: "Peter O. Brackett" <ab4bc@ix.netcom.com>
Subject: CW versus hi speed digital etc.
Bob:
Stop trashin us here...
No it doesn't!
Especially not before old fashioned RTTY!
What kind of crappy decoder and filters are you running on the receive end?
Peter K1PO
Madison, AL
"Bob Lewis" <aa4pb@erols.com> wrote in message
news:8jocnv$f8o$1@bob.news.rcn.net...
> > Try high speed CW on HF with a keyboard program and high
> > speed CW reader program, it often works as well as, or better
> > than, at the same speeds, more modern digital modes on the
> > HF channel.
> >
> You're dreaming! I've worked machine CW at 80 to 90 WPM on HF and it
> worked pretty well *with an excellent signal to noise ratio*. It falls
> apart pretty quickly when the SNR drops - long before any of the
> modern digital modes including plain old RTTY.
>
>
>
------------------------------
Date: Sun, 2 Jul 2000 17:33:53 -0500
From: "Peter O. Brackett" <ab4bc@ix.netcom.com>
Subject: CW versus hi speed digital etc.
Gary:
Heh, heh...
Gary, this is unlike you! Usually you are right on point.
But here you are WRONG.
There are some aspects of analog in hand sent CW, this would be interperted
only as a timing "jitter" effect which all digital communications systems
from SONET lightwave systems to ELF submarine data systems, have to various
extents.
In fact even this aspect of CW has been addressed by coherent CW enthusiasts
who have addressed the timing and synchronous detection problems you alluded
to.
Also... from a channel coding and modulation viewpoint, CW can easily be
transmitted using a variety of modulations from FSK to PSK, to whatever. It
just then makes direct copy of the sound "by ear" less familiar to
operators, a conversion device to convert back to a keyed tone would suffice
for human readability.
Often when I run CW from the keyboard with computer decoding at speeds up to
100 wpm and greater no human could ever copy it anyway.
Gary despite what you say, CW is truly digital!
By anybody's definition, what else would it be?
Always was digital, always will be digital.
It is so advanced in it's design concepts that it is not even a simple
binary system, in fact it is a multi-level digital logic code.
It uses a ternerary code alphabet with three symbols, space, dot, and dash
these three symbols could be assigned the labels, A, B, and C and sent by
many modulation methods. Up to and including modern trellis coded, lattice
coded or turbo coded modulations. What???
Even as CW is conventionally encoded and transmitted this ternary channel
code incorporates a highly efficient source coding algorithm which is
variable length and comma free. And this was all invented over 150 years
ago, long before Dr. Shannon was even born and the concepts of source coding
and channel coding were elucidated in the modern sense. In this respect CW
is similar to but more efficient than the Varicode that Peter Martinez
designed for PSK-31...
What???
Gary, if you cannot make intelligent contributions to this thread, I suggest
that you go back to the "rec.radio.amateur.antennas" NG, you know more about
antennas than you do digital communications!
And besides, my friend, heh, heh you'r spoiling my fun here on this
thread...
Peter K1PO
Madison, AL
"Gary Coffman" <ke4zv@bellsouth.net> wrote in message
news:ts9vlso67hcmgegn3dj2s2jnur7uec8dbt@4ax.com...
> On Fri, 30 Jun 2000 11:26:11 -0500, "Peter O. Brackett"
<ab4bc@ix.netcom.com> wrote:
> >CW is a digital mode, it can be high speed, it was the "first" mode as
well,
> >and it is both machine and human decodable.
>
> While the OOK modulation typically used is in a sense digital, ie an AM
encoding
> of on and off states of the baseband signal, Morse Code is not digital. It
is a timing
> code, all the coding information is in the timing edges, not in distinct
levels. While
> ideally that timing is derived from a fixed clock, in practice it
generally is not and
> must be considered more of an analog process.
>
> >Remarkable!
> >
> >Think about it, it is in fact the only digital mode that is decodable
both
> >by human operators and machines!
> >
> >Think about that! Try decoding Baudot RTTY by ear, or PacTor, or
Clover...
>
> Actually, some people can decode Baudot RTTY by ear. Of course the
> fact that it is normally sent at 60 WPM or faster makes that a bit
difficult,
> but slow it down to normal CW operating speeds and it is not difficult
> to decode by ear. In fact FSK is somewhat better (6 dB) than OOK
> because the ear is deciding between two distinct signal states and not
> between the presence and absense of a single signal against noise,
> which is a harder detection problem.
>
> In the old days, when using arc and alternator transmitters where it was
> technically difficult to generate OOK, operators used FSK to send Morse.
> It worked better than OOK then, and still does.
>
> >Try high speed CW on HF with a keyboard program and high speed CW reader
> >program, it often works as well as, or better than, at the same speeds,
more
> >modern digital modes on the HF channel.
>
> But it almost always occupies a larger bandwidth. The sharp timing edges
> essential of Morse coding causes the occupied bandwidth to be larger than
> modulation techniques using continuous phase modulations.
> >Let's stop trashing CW and leave it where it belongs as the; longest
> >standing, most cost efficient, most practically effective, human, and
> >machine decodable high speed digital mode in existence!
> >
> >In today's technology of the week era, what other robust industrial
To be continued in digest: hd_2000_178D
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