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PA2AGA > HDDIG 02.07.00 23:49l 222 Lines 7312 Bytes #-9413 (0) @ EU
BID : HD_2000_176C
Read: GUEST
Subj: HamDigitalDigest 2000/176C
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Sent: 000702/1356Z @:PI8HGL.#ZH1.NLD.EU #:57649 [Den Haag] FBB $:HD_2000_176C
From: PA2AGA@PI8HGL.#ZH1.NLD.EU
To : HDDIG@EU
Date: Sun, 02 Jul 00 14:23:01 MET
Message-Id: <hd_2000_176C>
From: pa2aga@pe1mvx.ampr.org
To: hd_broadcast@pa2aga.ampr.org
X-BBS-Msg-Type: B
ago.
Simple but elegant examples and illustrations of modern source and channel
coding technology are readily and easily analyzed in good old fashioned CW.
Thoughts, comments?
Peter K1PO
"Hamish Moffatt VK3SB" <hamish@cloud.net.au> wrote in message
news:IPb75.280$I43.1705@news1.eburwd1.vic.optushome.com.au...
> Peter O. Brackett <ab4bc@ix.netcom.com> wrote:
> > CW is not low speed. And... CW is digital!
>
> Not this line again Peter. It's getting old.
>
> > 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.
>
> CSMA yes, CD not really.
>
> > 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!
>
> But let's not promote it above other modes either. It doesn't deserve
that.
>
> I'd like to see you implement FEC in human-to-human CW!
>
> Hamish
> --
> Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>
------------------------------
Date: Sat, 1 Jul 2000 00:32:29 -0500
From: "Peter O. Brackett" <ab4bc@ix.netcom.com>
Subject: CW versus hi speed digital etc.
Hamish:
[snip]
"> CSMA yes, CD not really.
>[snip]
Ever run a high speed CW net as net control station with about 20 - 30
participants checking in and handling traffic? Well I have... tune in to
some of the (now slowly fading away) high speed CW NTS traffic nets here in
the USA.
Heh, heh. Collision Detect (CD) indeed!
BTW... do you know who the inventor of CSMA-CD was? Hint, he lives in HI.
Did you know that he was/is a ham?
[snip]
> I'd like to see you implement FEC in human-to-human CW!
[snip]
Hamish, you ignorant rascal, you talking about bandwidth IN-efficient
implementations where the channel coding and modulation are separated -OR-
about modern bandwidth efficient channel coding such as lattice, trellis,
and turbo coded modulation?
Because if it's the latter a simple analysis will tell you that you are dead
wrong, that's what every human CW operator does.
I can tell that you are not a very proficient CW operator or you would
know...
How do you think high speed CW operators can copy way ahead of their paper
copy [pencil or keyboard] in their heads?
It's called FEC...
Amazing how the human being/brain developed signal and information
processing techniques "in situ" so to speak, and how modern era
communications and information theoretic concepts and algorithms emulate
what human code copiers do instinctively...
More???
Peter K1PO
------------------------------
Date: Sat, 01 Jul 2000 07:45:28 GMT
From: hamish@cloud.net.au (Hamish Moffatt VK3SB)
Subject: CW versus hi speed digital etc.
Peter O. Brackett <ab4bc@ix.netcom.com> wrote:
> Hello, how's the wx down under mate?
A bit cold here mate! My kangaroo is really feeling the cold
and the crocodile has gone north for the winter!
> Perhaps now we can all get back to other less emotional issues and really
> begin to get ham radio folks to , understand, and answer exam questions on
> digital communications.
I agree. I wouldn't include CW in that list though. It is simple
and moderately elegant, but it isn't as good a performer as the newer
modes. For one thing, on-off keying is less bandwidth efficient
than phase-shift keying, if I recall correctly.
I operate digital modes almost entirely. (Hellschreiber mostly;
admittedly, that's not digital but it's in the same group. Occasionally
PSK31, MT63, Throb etc. Also APRS on FM packet.) But I've never operated
CW. If I did, it would because it's different, not because it's
superior.
73
Hamish
--
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>
------------------------------
Date: Sat, 01 Jul 2000 07:50:04 GMT
From: hamish@cloud.net.au (Hamish Moffatt VK3SB)
Subject: CW versus hi speed digital etc.
Peter O. Brackett <ab4bc@ix.netcom.com> wrote:
> How do you think high speed CW operators can copy way ahead of their paper
> copy [pencil or keyboard] in their heads?
> It's called FEC...
I wouldn't call that FEC at all. It sounds just like having a good
memory to me!
Hamish
--
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>
------------------------------
Date: Fri, 30 Jun 2000 13:28:47 -0400
From: "Mark Flanagan" <markf@cshore.com>
Subject: Digipan Software for PSK-31
I have just hooked up my rig to receive PSK-31. I downloaded a couple
programs but after Steve (WB8IMY) Ford's review of Digipan in QST I went
with that. I really don't have it all figured out yet and also have yet to
get the wiring right for sending. I would like to hear your comments on
which program you find best for which PSK-31 application. My uses will be
strictly DX, ragchewing and logging.
Also, what seems to be the best method for keying, using the computer's
serial port or the rig's vox?
--
Mark Flanagan, K1MKF
k1mkf@qsl.net
http://www.qsl.net/k1mkf/
------------------------------
Date: Fri, 30 Jun 2000 18:33:59 -0400
From: "Bob Lewis" <aa4pb@erols.com>
Subject: Digipan Software for PSK-31
> would like to hear your comments on which program you
> find best for which PSK-31 application
I suppose you'll get many opinions on that - software is changing all
the time. My personal preferences are DigiPan and WinPsk. Both have a
very nice user interface. DigiPan has the advantage of displaying a
"slice" of the band if you use wide receiver IF filters. You can then
see all the signals in that "slice" displayed and click on any one to
print it. The disadvantage of using a wide receiver filter is that
your receiver AGC can be subjected to strong signals in the wide
passband. Using a narrow filter in the receiver IF protects the
receiver AGC from signals outside the narrow passband but now you have
to tune in PSK signals with the receiver's tuning knob instead of
clicking on them with the mouse. If I'm using narrow filters then I
prefer WinPSK over DigiPan mainly because the smaller waterfall
display seems better suited to the narrower IF.
> Also, what seems to be the best method for keying, using
> the computer's serial port or the rig's vox?
I'd highly recommend PTT via the serial port. Some rigs work fine with
VOX and some overdrive the audio in order to get reliable VOX keying.
An additional problem with VOX can be that you forget to turn it off
and end up sending all those nice computer sounds over the air. With
PTT the computer sounds don't get transmitted because the PSK software
does not key the rig.
------------------------------
Date: Sat, 01 Jul 2000 00:24:56 GMT
From: "George , W5YR" <w5yr@att.net>
Subject: Digipan Software for PSK-31
I use the Kachina radio which may influence how I approach the situation
Bob described, but for what it is worth, here are my two cents.
My bottom line is that I *NEVER* touch the dial frequency of the Kachina
while operating PSK31. I set the dial for 14.070 and use a 3.5 KHz filter
To be continued in digest: hd_2000_176D
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