CW on the big screen

[AA4ZZ at aol.com]

In a message dated 96-07-06 09:02:44 EDT, jfeustle at UOFT02.UTOLEDO.EDU writes:

>After all the discussion on the contest reflector about the impending
>demise of CW, I found it fascinating to see this "out-of-date technology"
>portrayed in such a positive light in this summer's hit movie "Independence
>Day."
>
>

Also check out the ham sending cw in the new movie "Phenomonon" staring John
Travolta.My girlfriend even spotted the qsl cards on the shack wall.

73 Paul AA4ZZ

>From k0wa at southwind.net (Lee Buller)  Mon Jul  8 14:45:51 1996
From: k0wa at southwind.net (Lee Buller) (Lee Buller)
Date: Mon, 08 Jul 1996 08:45:51 -0500
Subject: Titan Gold
Message-ID: <1.5.4.32.19960708134551.00692f34 at southwind.net>

At 10:10 PM 7/7/96 -0400, you wrote:
>>I just spoke with Ten Tec yesterday about the Titan amp.  They have plans to
>>bring back the Titan for one last production run.  TT is calling it
>>Titan Gold. Price about $3375.
>
>For that price, is it 14 or 24 carat?
>
><grin>
>
>Bill Coleman, AA4LR, AA96LR      Mail: aa4lr at radio.org
>Quote: "Not in a thousand years will man ever fly!"
>            -- Wilbur Wright, 1901
>
>
Wow.....

Must be left over parts they need to get off the inventory shelf.  Great
amp.  I would place it neck and neck to ETO.

Lee Buller
k0wa at southwind.net



>From aa4lr at radio.org (Bill Coleman AA4LR)  Mon Jul  8 17:11:39 1996
From: aa4lr at radio.org (Bill Coleman AA4LR) (Bill Coleman AA4LR)
Date: Mon, 8 Jul 1996 12:11:39 -0400
Subject: cw forever?
Message-ID: <v01540b00ae06ddb6c68d@[198.242.115.141]>

>At 12:38 PM 7/3/96 -0400, you wrote:
>>>I would like to hear from contesters with digital mode and cw experience
>>>regarding their thoughts on how cw, rtty, and state of the art digital
>>>modes compare for contest-style weak signal work.
>>
>>Theoretically, CW doesn't stand a chance.
>
>Yes,  but try hearing (seeing) those weak digital signals
>on a busy band during a digital contest!  Or,  actually,
>try to find them just calling a random CQ;  just about
>not possible.  PACTOR,  etc all work to skeds,  as far
>as I know (which really isn't much!).

I think the answer lies in a) better TUs and b) better protocols. You could
even invent a protocol for totally automated digital contesting. But, if
you take away too much of the human element in contesting, it ceases to be
a challenge and therefore fun.

If the goal is simply to move information around, CW doesn't stand a chance
against well-implemented digital modem techniques.

Bill Coleman, AA4LR, AA96LR      Mail: aa4lr at radio.org
Quote: "Not in a thousand years will man ever fly!"
            -- Wilbur Wright, 1901



>From TREY at TGV.COM (Trey Garlough)  Mon Jul  8 17:23:37 1996
From: TREY at TGV.COM (Trey Garlough) (Trey Garlough)
Date: Mon, 8 Jul 1996 09:23:37 -0700 (PDT)
Subject: CW on the big screen
Message-ID: <836843017.298865.TREY at tgv.com>

> After all the discussion on the contest reflector about the impending
> demise of CW, I found it fascinating to see this "out-of-date technology"
> portrayed in such a positive light in this summer's hit movie "Independence
> Day."

Yep.  Quite a flick.  Computer geeks, radio hams, and pilots save the
world.  Suchadeal!  What could be better?

And for those of you who saw the movie, it serves as an important
reminder as to what can happen when you don't change your password
since the 1950s.  To quote Cliff Stoll, treat your password like a
toothbrush.  Change it every few months and don't share it with
anyone.

--Trey, WN4KKN/6

>From MARKV at SNC-LAVALIN.COM (Vitaly Markhasin)  Mon Jul  8 17:27:27 1996
From: MARKV at SNC-LAVALIN.COM (Vitaly Markhasin) (Vitaly Markhasin)
Date: Mon, 08 Jul 1996 12:27:27 -0400
Subject: Info required
Message-ID: <s1e0feae.024 at SNC-LAVALIN.COM>

I am looking for E-Mail address of "CQ" Magazine and/or
Steve Bolia N8BJQ - their WPX Contest Director.
Your help would be very much appreciated.
Thank you.
73! VE6JO

P.S. My E-Mail Address:  MARKV at SNC-LAVALIN.COM
 

>From bsmith at tx.ncsu.edu (Brent Smith)  Mon Jul  8 17:42:22 1996
From: bsmith at tx.ncsu.edu (Brent Smith) (Brent Smith)
Date: Mon, 8 Jul 1996 12:42:22 -0400
Subject: cw forever?
References: <v01540b00ae06ddb6c68d@[198.242.115.141]>
Message-ID: <960708124225.ZM7463 at nt2>


>From kr4uj at mindspring.com (Paul Pescitelli)  Mon Jul  8 18:53:18 1996
From: kr4uj at mindspring.com (Paul Pescitelli) (Paul Pescitelli)
Date: Mon, 8 Jul 1996 12:53:18 -0500
Subject: NA-076 Iota Activation
Message-ID: <v01530500ae06fb5702cc@[205.164.235.7]>

For those interested, KR4DL and I will activate Cedar Key, NA-076, as a
multi-single entry in the IOTA contest.  We will attempt to activate all
bands (don't expect much out of 10 and 15 meters) just before and during the
contest in mixed-mode.

73,  PAUL KR4UJ

"Little antennas, low to the ground,
 don't get out much, but don't blow down."



>From k6sti at n2.net (Brian Beezley)  Mon Jul  8 18:00:38 1996
From: k6sti at n2.net (Brian Beezley) (Brian Beezley)
Date: Mon, 8 Jul 1996 10:00:38 -0700
Subject: UNKN422.WAV
Message-ID: <199607081700.KAA13879 at ravel.n2.net>

[Trey, I originally posted this message to other reflectors.  It's pretty
technical and doesn't deal directly with contesting.  But after I sent it
off, I realized that the thing that really motivated me about this problem
was the personal challenge and radio-sport aspect.  The same kind of thing
that motivates contesters, I believe.  And since some contesters think
they're real CW hotshots, they might get a kick out of taking a stab at
this.  (They're in for a quick dose of CW humility, I assure you!)  I'm
passing this on to you to post or not as you see fit.  I can't decide
whether it's suitable for the contest reflector.]


>Sounds great.  Post it.


Mike, I wanted to tell you about my ongoing efforts to crack your
UNKN422.WAV EME callsign mystery.  I'm motivated primarily by the technical
challenge; the $100 prize you offer will barely pay for the electricity I've
expended!  I think this is a really neat challenge you've come up with, so
I'm copying this note to the EME reflector and to the TAPR HFSIG reflector
(where there's recently been some discussion of CW decoding) in hopes of
spurring others to try tackling the problem (perhaps one more time).

Earlier this week I seriously looked at the problem for the first time.  I
spent the better part of two days on it.  Listening to the file without
benefit of signal processing, I could just barely hear a tone pop out of the
noise for a second or two.  (The first time I listened, I heard only noise.)
This was so unexpected that I downloaded the file again
(http://www.webcom.com/af9y) to make sure I had the right one!

I cobbled together a special version of DSP Blaster to process the .WAV file
instead of real-time, sound-card audio.  I found neither its LMS noise
reduction nor 15-wpm matched filter helpful.

For quite some time I've wondered whether a matched filter really is optimal
for processing CW signals for detection by ear.  A matched filter is optimal
for threshold detection of signals in noise under certain conditions, but I
wonder whether the conditions hold when preprocessing a signal for detection
by ear.  I don't know what the ear/brain does to detect CW, but it's
certainly more complex than simple thresholding.  For example, for many
years I've preferred to use an SSB-bandwidth filter to recover weak HF CW
signals rather than a 500-Hz CW filter.  The additional noise somehow makes
signal detection seem easier.  (I haven't run a test to verify that it
actually makes detection more reliable).  I find listening through extremely
narrow filters somewhat disconcerting because they shape the
background-noise spectrum approximately to that of a sine wave at the filter
center frequency.  So your ear must then distinguish between the desired
sine wave and weaker ones that bobble around in the background.  Even though
I estimate that DSP Blaster's 15-wpm matched filter improves CW detection by
perhaps 1 dB for my ears, I sometimes prefer to detect CW in wideband noise
(even though listening for long periods that way can be fatiguing).  (It's
interesting that most ops seem to vastly prefer narrowband CW filters.)

Since UNKN422 remained a mystery, I tried implementing a signal-processing
technique I had planned for DSP Blaster version 2.  I've had my Pentium-100
for one year and this was the first time I ever ran up against its
processing-power limits.  I had to recode the algorithm using
Pentium-specific, floating-point optimizations (pipelining).  It immediately
yielded clearly audible dots and dashes throughout the .WAV file.  Now I was
getting somewhere!  Right away I discovered I had misestimated the sending
speed.  I now was sure that recovering the callsign would be easy.  I
visualized the "K6STI Cracks UNKN422 with Secret Algorithm" headlines.  So I
listened carefully for some time, wrote down some possible calls, and
consulted your list of 1000 EME callsigns, among which is the mystery
callsign.  Hmmmm...nothing matched very well.  After more listening I found
that I could mentally transform any given sound segment into my current
best-guess callsign with very little wishful thinking!  I was familiar with
this phenomenon but thought I'd outgrown it years ago.  I've heard 160-meter
operators talk about it and I imagine it must be old-hat to you EME ops.

Twice I was quite sure of the callsign.  I was ready to submit my winning
entry and thought I'd take one last listen.  Then I discovered that I heard
completely different letters by altering playback speed and pitch!  This was
quite a shock to someone who prides himself on his hearing acuity.  Although
the dots and dashes are readily audible, the signal level is quite variable.
(I assume this is due to some kind of moon multipath.)  Often the code
elements seem to have holes in them or to be smeared together.  Sometimes
it's not clear whether it's one long dash or a dot and dash.  I also
discovered that my callsign choices tended to depend critically on one or
two crucial letters.  It was very easy to persuade myself to ignore other
sounds that really didn't fit but clearly weren't important because, after
all, surely this was the correct callsign!  The fascinating thing about this
problem is that it involves both a technical and psychological challenge.

In frustration, I tried cascading a semi-matched filter with the
processor-intensive technique.  It didn't help.  I really didn't want to
guess at a callsign, so I kept listening over and over, tweaking algorithm
constants.  More new callsigns.  I got so involved with the problem that my
sleeping schedule became disrupted.  When I reluctantly stopped listening to
take a much-needed nap, I fitfully dreamed about weak CW!  I decided it was
time to return to normal life and finally gave up on the problem late one
night.  Temporarily.

I have one more technical trick to pull.  In fact, although it's not
implemented in the current version, this trick was the whole reason I
started the DSP Blaster project.  I plan to implement this technique in
version 2 along with the processor-intensive algorithm.  I think the
combination may provide enough S/N enhancement to yield a solution.  It will
take some experimentation to get right and a fair amount of programming to
implement, so I expect it will be a little while in coming.  Meanwhile,
maybe someone else will decide to try a concerted attack on the problem.

I think your UNKN422.WAV challenge would be a really neat term project for
university engineering students.  It's a fascinating mystery, involves
signal-processing theory, practical engineering, programming techniques, and
human perception and psychology.  It's really a lot of fun!  You might try
to locate an engineering professor somewhere who is also a ham and lay it on
him.


                      73--Brian, K6STI
                          k6sti at n2.net


>From MARKV at SNC-LAVALIN.COM (Vitaly Markhasin)  Mon Jul  8 18:10:59 1996
From: MARKV at SNC-LAVALIN.COM (Vitaly Markhasin) (Vitaly Markhasin)
Date: Mon, 08 Jul 1996 13:10:59 -0400
Subject: No subject
Message-ID: <s1e10913.065 at SNC-LAVALIN.COM>

set norepro
quit