Message-ID: <sa77e7b7.062@jazzfm.com>
Date: Wed, 31 Jan 2001 10:23:17 +0000
From: "Martin Charman" <Martin@jazzfm.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: CW etc
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII; format=flowed
Content-Transfer-Encoding: 8bit
Content-Disposition: inline
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

I was taught that the term CW (Continuous Wave), was coined to differentiate between the 'pure' oscillations generated by valves or HF rotary generators and the quenched or interrupted oscillations generated by spark transmitters?

Martin G4FKK

>>> Walter Blanchard <blanch@pncl.co.uk> 31 January 2001 07:51:29 >>>
For some reason this didn't seem to make it onto the reflector first time 
round so here goes again:

Recent discussions on "CW" and "Morse" have brought up some interesting 
points.  Does a mode that is only visually recognisable via a machine count 
as "Morse" , or is it another manifestation of digital modulation?  If the 
effective bandwidths used with QRSS are in the sub-Hertzian range does that 
make normally-sent "Morse" a wideband mode that should have no place at 
LF?  Consider :

"CW" - "continuous wave" - means just that; a steady unbroken unmodulated 
carrier wave; "N0N"  (or "A0" in old money).  Morse code is mainly sent by 
interrupting the carrier so how can it possibly be "CW"?  Only amateurs 
consider "Morse" and "CW" to be synonymous which is a pity because it 
clouds our thinking.  Sending Morse code by interrupting the carrier is 
designated "A1A" (or "150HA1AAN" for typical ham morse if you want to be 
pedantic!)  - meaning a single carrier amplitude-modulated by a telegraphy 
signal.  Amplitude modulation (on/off keying) always generates sidebands so 
it is by no means "narrow-band" by modern standards.  In fact, the faster 
Morse is sent the more continuous and wider are the sidebands; the extreme 
example of a fast interrupted-carrier system is radar pulsing on/off in 
nanoseconds and look how wideband that is.  So, "QRSS", because it switches 
only slowly and at long intervals is much more entitled to the narrow-band 
designation than normal Morse and therefore has more entitlement to be in 
the "narrow-band" segment.  Nobody has defined when exactly slowly-sent 
Morse ceases to be A1A and becomes N0N.  Perhaps we shouldn't press the 
point, we don't have "N0N" in our licenses!

And what constitutes a QSO under QRSS conditions?  The exchange of 
information presumably, but what should be the minimum time-lapse  between 
sending and receiving?  Seconds?  Minutes?  Hours?  Days?   If I send you a 
letter (or even an email) and you reply days later I have achieved 
communication with you and the time-lapse is relatively unimportant so why 
should radio be different?  Just perception?.

Then, perhaps we should have different categories of contact.
An "instant" QSO using "fast" Morse such as we all know and love from HF is 
quite difficult to do at LF other than at relatively short ranges. To go 
Transatlantic in this mode will require a very "full" 1 watt plus two very 
sophisticated Morse ears and a lot of luck and is probably not open to 
those who don't have the real estate and cash to put up semi-professional 
antenna farms.  Nevertheless we don't begrudge the lucky few who can do so 
their contest wins on the HF bands so we shouldn't here either. So, one 
category for "fast" modes with the proviso that they must complete a 
specified minimum QSO within, say, one minute.
Coming down from such heights we get the many who can only put up "small" 
antennas and will get electrocuted if they try pushing them to 1 watt 
radiated. Their only hope is visual QRSS so a second category for "slow" 
modes which would have to complete a QSO within, say, one hour.

Please, no arguments about "players" versus "gentlemen" - you might end up 
in the wrong category!

Walter G3JKV.