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Ham-Digital Digest Sat, 1 Jul 2000 Volume 2000 : Issue 176
Today's Topics:
CW versus hi speed digital etc. (9 msgs)
Digipan Software for PSK-31 (3 msgs)
Field day review (MixW rocks)(TrueTTY OK too!)
how does PSK31 really work?
Icom 706 and Soundcard
NEW AMATEUR RADIO WEBSITE!
Send Replies or notes for publication to: <Ham-Digital@UCSD.Edu>
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We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
Loop-Detect: Ham-Digital:2000/176
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Date: Fri, 30 Jun 2000 11:26:11 -0500
From: "Peter O. Brackett" <ab4bc@ix.netcom.com>
Subject: CW versus hi speed digital etc.
Graham:
CW is not low speed. And... CW is digital!
It is only low speed when sent at human sending and receiving speeds, say up
to about 50 wpm.
And... even when processed by humans on the receiving end the signal
processing techniques are of the most modern kind, utilizing both CSMA-CD,
source coding and maximul likelihood (a.k.a Viterbi) decoding.
The so-called modern detection technologies such as Soft Viterbi Decoding,
are simply mathematical, digital signal processing algorithms, which
emulate, but not very well, what every good human decoder does.
Don't let anyone fool you...
Soft Viterbi Decoding -- a.k.a. using soft decisions, and the analog errors
detected therefrom, to improve on a maximum liklihood detection algorithm.
Viterbi Decoding or Maximum Likelihood decoding or detection is nothing more
or less than a "fancy" pseudo-mathematical name for an "exhaustive search"
of the possible symbols sent given the noisy signal received! Just exactly
what we humans do when processing CW reception.
Note that CW can also be decoded by a machine algorithm that implements Soft
Viterbi Decoding, but because of implementation losses those machine
algorithms have yet to match what a good human decoder can do at human
speeds.
Then note carefully that CW can be sent and received at Gbps speeds by
machines in the appropriate bands. And those transmission may readily be
recorded and played back slowly for direct human translation if desired.
CW can be machine sent and received at much higher than human processing
speeds even on the HF bands and as such it has many of the characteristics
of the so called modern digital modes and certainly exceed some of them in
communications efficiencey.
In fact many of the characteristics of CW transmission such as Huffman data
compression [source coding] and CSMA-CD [Carrier Sense Multiple Access with
Collision Detection], and maximum likelihood decoding [MLD a.k.a Viterbi
Decoding] were first pioneered with CW.
Consider even today that, Peter Martinez' Varicode data compression (The
Huffman-like source coding algorithm) invented by him for the new PSK-31
digital mode, although having a somewhat larger symbol set (alphabet), is
not as efficient as the built in comma free variable length source coding of
CW!
Measure the coding efficency yourself of Varicode versus CW yourself if you
don't believe me.
Were'e going backwards... Go figure?
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.
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...
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.
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 strength
digital transmisson technology can match CW in its' price/performance
characteristics, and its' pioneering use of most of today's so-called modern
communications technologies?
Peter K1PO
"Graham Ranft" <ranftg@interact.net.au> wrote in message
news:1uV65.169$JQ6.16999484@news.interact.net.au...
> G'day & Greetings!
>
> I've used both CW and digital. [1200 and 9600 bd. sats packet and pactor
I]
>
> There is still, I think nothing, quite like the skill and pleasure of a
good CW
> qso-mine was a cw qso via oscar 13 sending a message from a daughter to
> her father on the otherside of the world in hospital.
>
> Im am now not active, but if I were to go on air again it would be using
CW.
>
> Let us not flame each other but respect our differing interests.
>
> Graham formerly VK7ZO and VK1ZO
>
> Graham in Canberra Australia
>
>
>
> .
>
>
>
>
------------------------------
Date: Fri, 30 Jun 2000 18:50:10 GMT
From: horseshoestew@my-deja.com
Subject: CW versus hi speed digital etc.
In article <1uV65.169$JQ6.16999484@news.interact.net.au>,
"Graham Ranft" <ranftg@interact.net.au> wrote:
> G'day & Greetings!
>
> I've used both CW and digital. [1200 and 9600 bd. sats packet and
pactor I]
9600 is high speed, huh?
> There is still, I think nothing, quite like the skill and pleasure of
a good CW
> qso-mine was a cw qso via oscar 13 sending a message from a daughter
to
> her father on the otherside of the world in hospital.
You could have gotten that message there a lot faster with a "real" hi-
speed (>1Mbps) Internet connection.
> Im am now not active, but if I were to go on air again it would be
using CW.
Roadrunner, roadrunner, roadrunner goes BEEP-BEEP...
> Let us not flame each other but respect our differing interests.
I don't mind that you like to use Morse(I've even used it on
occasion). But please don't tell me not to flame the pro-code
requirements die-hards. Those backwards-thinking nincompoops
are "supporting Morse" for a TOTALLY different reason.
Supporting Morse Code and supporting Morse Code requirments are two
different things.
> Graham formerly VK7ZO and VK1ZO
> Graham in Canberra Australia
Stewart - N0MHS
--
Wireless High-Speed Networking Information:
http://www.geocities.com/SiliconValley/Monitor/2254/radio.html
Public Radio Services Information:
http://www.geocities.com/SiliconValley/Monitor/2254/radio2.html
Sent via Deja.com http://www.deja.com/
Before you buy.
------------------------------
Date: Fri, 30 Jun 2000 15:21:17 -0500
From: "Peter O. Brackett" <ab4bc@ix.netcom.com>
Subject: CW versus hi speed digital etc.
I say down with Morse Code licensing requirements, but up with Morse Code!
To be continued in digest: hd_2000_176B
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